From dafb6ec0eb24f32386422b16a215591c223b7a2f Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Mon, 6 Aug 2018 17:34:09 -0500
Subject: [PATCH 01/18] Start hackney; add ex_aws so tests will run

---
 mix.exs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mix.exs b/mix.exs
index bc3e785..6d54764 100644
--- a/mix.exs
+++ b/mix.exs
@@ -17,7 +17,7 @@ defmodule CloudWatch.Mixfile do
   #
   # Type "mix help compile.app" for more information
   def application do
-    [applications: [:logger]]
+    [applications: [:logger, :hackney]]
   end
 
   # This makes sure your factory and any other modules in test/support are compiled
@@ -35,7 +35,9 @@ defmodule CloudWatch.Mixfile do
   #
   # Type "mix help deps" for more examples and options
   defp deps do
-    [{:aws, "~> 0.5.0", optional: true},
+    [
+     {:aws, "~> 0.5.0", optional: true},
+     {:ex_aws, "~> 2.0"},
      {:httpoison, "~> 0.11.1"},
      {:credo, "~> 0.4.13", only: :dev},
      {:mock, "~> 0.2.0", only: :test},

From ce6819303c6e74b1d570d76379b5770177202db0 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Mon, 6 Aug 2018 17:34:28 -0500
Subject: [PATCH 02/18] Update deps

---
 mix.lock | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/mix.lock b/mix.lock
index d6ce20b..eea41e7 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,20 +1,23 @@
-%{"aws": {:hex, :aws, "0.5.0", "e3916abd9d1fb4c182cbeac8a964ddeb32de9b20d441b66fba838ade06a4a278", [:mix], [{:httpoison, "~> 0.11.1", [hex: :httpoison, repo: "hexpm", optional: false]}, {:poison, "~> 3.1", [hex: :poison, repo: "hexpm", optional: false]}, {:timex, "~> 3.1", [hex: :timex, repo: "hexpm", optional: false]}], "hexpm"},
+%{
+  "aws": {:hex, :aws, "0.5.0", "e3916abd9d1fb4c182cbeac8a964ddeb32de9b20d441b66fba838ade06a4a278", [:mix], [{:httpoison, "~> 0.11.1", [hex: :httpoison, repo: "hexpm", optional: false]}, {:poison, "~> 3.1", [hex: :poison, repo: "hexpm", optional: false]}, {:timex, "~> 3.1", [hex: :timex, repo: "hexpm", optional: false]}], "hexpm"},
   "bunt": {:hex, :bunt, "0.1.6", "5d95a6882f73f3b9969fdfd1953798046664e6f77ec4e486e6fafc7caad97c6f", [:mix], [], "hexpm"},
   "certifi": {:hex, :certifi, "1.2.1", "c3904f192bd5284e5b13f20db3ceac9626e14eeacfbb492e19583cf0e37b22be", [:rebar3], [], "hexpm"},
   "combine": {:hex, :combine, "0.9.6", "8d1034a127d4cbf6924c8a5010d3534d958085575fa4d9b878f200d79ac78335", [:mix], [], "hexpm"},
-  "credo": {:hex, :credo, "0.4.13", "0e9d0479c7e0591e36b093bf17fbdde012e2a69b5571e2df8d0b75b4fc8adc74", [:mix], [{:bunt, "~> 0.1.6", [hex: :bunt, repo: "hexpm", optional: false]}], "hexpm"},
+  "credo": {:hex, :credo, "0.4.14", "594a965ae2224997fae9e705e881983911a052c701b05bd3bcf89af44b5f6b45", [:mix], [{:bunt, "~> 0.1.6", [hex: :bunt, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.2.2", "f718159d6b65068e8daeef709ccddae5f7fdc770707d82e7d126f584cd925b74", [:mix], [], "hexpm"},
+  "ex_aws": {:hex, :ex_aws, "2.1.0", "b92651527d6c09c479f9013caa9c7331f19cba38a650590d82ebf2c6c16a1d8a", [:mix], [{:configparser_ex, "~> 2.0", [hex: :configparser_ex, repo: "hexpm", optional: true]}, {:hackney, "1.6.3 or 1.6.5 or 1.7.1 or 1.8.6 or ~> 1.9", [hex: :hackney, repo: "hexpm", optional: true]}, {:jsx, "~> 2.8", [hex: :jsx, repo: "hexpm", optional: true]}, {:poison, ">= 1.2.0", [hex: :poison, repo: "hexpm", optional: true]}, {:sweet_xml, "~> 0.6", [hex: :sweet_xml, repo: "hexpm", optional: true]}, {:xml_builder, "~> 0.1.0", [hex: :xml_builder, repo: "hexpm", optional: true]}], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.16.2", "3b3e210ebcd85a7c76b4e73f85c5640c011d2a0b2f06dcdf5acdb2ae904e5084", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}], "hexpm"},
   "gettext": {:hex, :gettext, "0.13.1", "5e0daf4e7636d771c4c71ad5f3f53ba09a9ae5c250e1ab9c42ba9edccc476263", [:mix], [], "hexpm"},
   "hackney": {:hex, :hackney, "1.8.6", "21a725db3569b3fb11a6af17d5c5f654052ce9624219f1317e8639183de4a423", [:rebar3], [{:certifi, "1.2.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "5.0.2", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.1", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
   "httpoison": {:hex, :httpoison, "0.11.2", "9e59f17a473ef6948f63c51db07320477bad8ba88cf1df60a3eee01150306665", [:mix], [{:hackney, "~> 1.8.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
   "idna": {:hex, :idna, "5.0.2", "ac203208ada855d95dc591a764b6e87259cb0e2a364218f215ad662daa8cd6b4", [:rebar3], [{:unicode_util_compat, "0.2.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
-  "meck": {:hex, :meck, "0.8.4", "59ca1cd971372aa223138efcf9b29475bde299e1953046a0c727184790ab1520", [:make, :rebar], [], "hexpm"},
+  "meck": {:hex, :meck, "0.8.11", "2c39e15ec87d847da6cf69b4a1c4af3fd850ae2a272e719e0e8751a7fe54771f", [:rebar3], [], "hexpm"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
   "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
-  "mock": {:hex, :mock, "0.2.0", "5991877be6bb514b647dbd6f4869bc12bd7f2829df16e86c98d6108f966d34d7", [:mix], [{:meck, "~> 0.8.2", [hex: :meck, repo: "hexpm", optional: false]}], "hexpm"},
+  "mock": {:hex, :mock, "0.2.1", "bfdba786903e77f9c18772dee472d020ceb8ef000783e737725a4c8f54ad28ec", [:mix], [{:meck, "~> 0.8.2", [hex: :meck, repo: "hexpm", optional: false]}], "hexpm"},
   "poison": {:hex, :poison, "3.1.0", "d9eb636610e096f86f25d9a46f35a9facac35609a7591b3be3326e99a0484665", [:mix], [], "hexpm"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.1", "28a4d65b7f59893bc2c7de786dec1e1555bd742d336043fe644ae956c3497fbe", [:make, :rebar], [], "hexpm"},
   "timex": {:hex, :timex, "3.1.21", "7d1ec0f73c4668bea71f38af6357d75992f356a7e032c69620c5e87ca4b95c66", [:mix], [{:combine, "~> 0.7", [hex: :combine, repo: "hexpm", optional: false]}, {:gettext, "~> 0.10", [hex: :gettext, repo: "hexpm", optional: false]}, {:tzdata, "~> 0.1.8 or ~> 0.5", [hex: :tzdata, repo: "hexpm", optional: false]}], "hexpm"},
   "tzdata": {:hex, :tzdata, "0.5.12", "1c17b68692c6ba5b6ab15db3d64cc8baa0f182043d5ae9d4b6d35d70af76f67b", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
-  "unicode_util_compat": {:hex, :unicode_util_compat, "0.2.0", "dbbccf6781821b1c0701845eaf966c9b6d83d7c3bfc65ca2b78b88b8678bfa35", [:rebar3], [], "hexpm"}}
+  "unicode_util_compat": {:hex, :unicode_util_compat, "0.2.0", "dbbccf6781821b1c0701845eaf966c9b6d83d7c3bfc65ca2b78b88b8678bfa35", [:rebar3], [], "hexpm"},
+}

From 18915faa1b77546f4482121c293520f88a6d6ed9 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Mon, 6 Aug 2018 17:34:57 -0500
Subject: [PATCH 03/18] Add access_key_id in config for tests

---
 test/cloud_watch_test.exs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/test/cloud_watch_test.exs b/test/cloud_watch_test.exs
index 17ad69a..fcaafa9 100644
--- a/test/cloud_watch_test.exs
+++ b/test/cloud_watch_test.exs
@@ -12,7 +12,10 @@ defmodule CloudWatchTest do
   setup_all do
     {:ok, _} = Cycler.start_link
     Logger.add_backend(@backend)
-    :ok = Logger.configure_backend(@backend, [format: "$message", level: :info, log_group_name: "testLogGroup", log_stream_name: "testLogStream", max_buffer_size: 39])
+    config = [format: "$message", level: :info, log_group_name: "testLogGroup",
+              log_stream_name: "testLogStream", max_buffer_size: 39,
+              access_key_id: "fake"]
+    :ok = Logger.configure_backend(@backend, config)
   end
 
   setup do

From f725b2348995dde3936ee1679a088d416328593a Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Mon, 6 Aug 2018 17:35:59 -0500
Subject: [PATCH 04/18] Read AWS config from instance metadata

---
 README.md          |  22 +++++--
 lib/cloud_watch.ex | 154 ++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 147 insertions(+), 29 deletions(-)

diff --git a/README.md b/README.md
index 04a2627..bbc2f4a 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ Add the backend to `config.exs`:
     utc_log: true
   ```
 
-Configure the following example to suit your needs:
+Following is a full example with the default values:
 
   ```elixir
   config :logger, CloudWatch,
@@ -46,10 +46,22 @@ Configure the following example to suit your needs:
     max_timeout: 60_000
   ```
 
-The `endpoint` may be omitted from the configuration and will default to
-`amazonaws.com`. The `max_buffer_size` controls when `cloud_watch` will flush
-the buffer in bytes. You may specify anything up to a maximum of 1,048,576
-bytes. If omitted, it will default to 10,485 bytes.
+CloudWatch flushes the buffer when it has collected `max_buffer_size` bytes of
+messages or `max_timeout` milliseconds have elapsed. `max_buffer_size` can be
+anything up to a maximum of 1,048,576 bytes. If omitted, it will default to
+10,485 bytes.
+
+CloudWatch supports getting AWS credentials and other defaults from
+[EC2 instance metadata](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html)
+
+In that case, a minimal configuration is:
+
+  ```elixir
+  config :logger, CloudWatch,
+    log_group_name: "api"
+  ```
+
+`log_stream_name` defaults to the instance id.
 
 ## Alternative AWS client library: ExAws
 
diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index 8c012b9..a0bab38 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -9,8 +9,20 @@ defmodule CloudWatch do
   alias CloudWatch.InputLogEvent
   alias CloudWatch.AwsProxy
 
-  def init(_) do
-    state = configure(Application.get_env(:logger, CloudWatch, []))
+  def init(_args) do
+    state = configure([])
+
+    # If AWS keys are not defined statically, get them from the instance metadata.
+    # This may fail while the instance is starting up, so retry quickly.
+    # Otherwise refresh every 10 minutes, as the keys expire periodically.
+    unless state.access_key_id do
+      if state.client do
+        Process.send_after(self(), :refresh_creds, 300_000)
+      else
+        Process.send_after(self(), :refresh_creds, 200)
+      end
+    end
+
     Process.send_after(self(), :flush, state.max_timeout)
     {:ok, state}
   end
@@ -39,7 +51,7 @@ defmodule CloudWatch do
   end
 
   def handle_event(:flush, state) do
-    {:ok, Map.merge(state, %{buffer: [], buffer_size: 0})}
+    {:ok, %{state | buffer: [], buffer_size: 0}}
   end
 
   def handle_info(:flush, state) do
@@ -48,6 +60,16 @@ defmodule CloudWatch do
     {:ok, flushed_state}
   end
 
+  def handle_info(:refresh_creds, state) do
+    state = configure_aws(state)
+    if state.client do
+      Process.send_after(self(), :refresh_creds, 300_000)
+    else
+      Process.send_after(self(), :refresh_creds, 200)
+    end
+    {:ok, state}
+  end
+
   def handle_info(_msg, state) do
     {:ok, state}
   end
@@ -60,34 +82,82 @@ defmodule CloudWatch do
     :ok
   end
 
+  @spec configure(Keyword.t) :: Map.t
   defp configure(opts) do
     opts = Keyword.merge(Application.get_env(:logger, CloudWatch, []), opts)
-    format = Logger.Formatter.compile(Keyword.get(opts, :format, @default_format))
-    level = Keyword.get(opts, :level, @default_level)
-    log_group_name = Keyword.get(opts, :log_group_name)
-    log_stream_name = Keyword.get(opts, :log_stream_name)
-    max_buffer_size = Keyword.get(opts, :max_buffer_size, @default_max_buffer_size)
-    max_timeout = Keyword.get(opts, :max_timeout, @default_max_timeout)
-
-    # AWS configuration, only if needed by the AWS library
-    region = Keyword.get(opts, :region)
-    access_key_id = Keyword.get(opts, :access_key_id)
-    endpoint = Keyword.get(opts, :endpoint, @default_endpoint)
-    secret_access_key = Keyword.get(opts, :secret_access_key)
-    client = AwsProxy.client(access_key_id, secret_access_key, region, endpoint)
-    %{buffer: [], buffer_size: 0, client: client, format: format, level: level, log_group_name: log_group_name,
-      log_stream_name: log_stream_name, max_buffer_size: max_buffer_size, max_timeout: max_timeout,
-      sequence_token: nil, flushed_at: nil}
-  end
-
-  defp flush(_state, _opts \\ [force: false])
+
+    state = %{
+      access_key_id: opts[:access_key_id],
+      secret_access_key: opts[:secret_access_key],
+      region: opts[:region] || metadata_region(),
+      endpoint: opts[:endpoint] || metadata_endpoint(),
+      client: nil,
+      buffer: [], buffer_size: 0,
+      level: opts[:level] || @default_level,
+      format: Logger.Formatter.compile(opts[:format] || @default_format),
+      log_group_name: opts[:log_group_name],
+      log_stream_name: opts[:log_stream_name],
+      max_buffer_size: opts[:max_buffer_size] || @default_max_buffer_size,
+      max_timeout: opts[:max_timeout] || @default_max_timeout,
+      sequence_token: nil, flushed_at: nil
+    }
+
+    if state.access_key_id do
+      %{state | client: AwsProxy.client(state.access_key_id, state.secret_access_key, state.region, state.endpoint)}
+    else
+      configure_aws(state)
+    end
+  end
+
+  defp configure_aws(state) do
+    case System.get_env("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI") do
+      nil ->
+        # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html
+        case get_metadata("http://169.254.169.254/latest/meta-data/iam/security-credentials/") do
+          {:ok, ""} ->
+            state
+          {:ok, role} ->
+            {:ok, json} = get_metadata("http://169.254.169.254/latest/meta-data/iam/security-credentials/" <> role)
+            creds = Poison.Parser.parse!(json)
+            access_key_id = Map.get(creds, "AccessKeyId")
+            secret_access_key = Map.get(creds, "SecretAccessKey")
+            region = state.region || metadata_region()
+            endpoint = state.endpoint || metadata_endpoint() || @default_endpoint
+            client = AwsProxy.client(access_key_id, secret_access_key, region, endpoint)
+
+            log_stream_name = state.log_stream_name || metadata_instance_id()
+
+            %{state | client: client, log_stream_name: log_stream_name}
+          _ ->
+            state
+        end
+      uri ->
+        # https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html
+        case get_metadata("http://169.254.170.2" <> uri) do
+          {:ok, json} ->
+            creds = Poison.Parser.parse!(json)
+            access_key_id = Map.get(creds, "AccessKeyId")
+            secret_access_key = Map.get(creds, "SecretAccessKey")
+            region = state.region
+            endpoint = state.endpoint || @default_endpoint
+            client = AwsProxy.client(access_key_id, secret_access_key, region, endpoint)
+            %{state | client: client}
+          _ ->
+            state
+        end
+    end
+  end
+
+  defp flush(state, opts \\ [force: false])
 
   defp flush(%{buffer: buffer, buffer_size: buffer_size, max_buffer_size: max_buffer_size} = state, [force: false])
     when buffer_size < max_buffer_size and length(buffer) < 10_000 do
       {:ok, state}
   end
-  
-  defp flush(%{buffer: []} = state, _opts), do: {:ok, state}  
+
+  defp flush(%{buffer: []} = state, _opts), do: {:ok, state}
+
+  defp flush(%{client: nil} = state, _opts), do: {:ok, state}
 
   defp flush(state, opts) do
     case AwsProxy.put_log_events(state.client, %{logEvents: Enum.sort_by(state.buffer, &(&1.timestamp)),
@@ -116,4 +186,40 @@ defmodule CloudWatch do
           |> flush(opts)
     end
   end
+
+  defp get_metadata(url) do
+    case HTTPoison.get(url) do
+      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+        {:ok, body}
+      _ ->
+        nil
+    end
+  end
+
+  defp get_metadata!(url) do
+    case HTTPoison.get(url) do
+      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+        body
+      _ ->
+        nil
+    end
+  end
+
+  defp metadata_endpoint do
+    get_metadata!("http://169.254.169.254/latest/meta-data/services/domain")
+  end
+
+  defp metadata_instance_id do
+    get_metadata!("http://169.254.169.254/latest/meta-data/instance-id")
+  end
+
+  defp metadata_region do
+    case HTTPoison.get("http://169.254.169.254/latest/meta-data/placement/availability-zone") do
+      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+        String.slice(body, Range.new(0, -2))
+      _ ->
+        nil
+    end
+  end
+
 end

From 5ee4565e9c0d4365ddd9ab433f6ea36f2dcc3f09 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Mon, 6 Aug 2018 18:50:41 -0500
Subject: [PATCH 05/18] Add explicit dep on poison

---
 mix.exs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mix.exs b/mix.exs
index 6d54764..6f35668 100644
--- a/mix.exs
+++ b/mix.exs
@@ -39,6 +39,7 @@ defmodule CloudWatch.Mixfile do
      {:aws, "~> 0.5.0", optional: true},
      {:ex_aws, "~> 2.0"},
      {:httpoison, "~> 0.11.1"},
+     {:poison, "~> 4.0"},
      {:credo, "~> 0.4.13", only: :dev},
      {:mock, "~> 0.2.0", only: :test},
      {:ex_doc, ">= 0.0.0", only: :dev}]

From 6c619bd87b96a7fc33c118d1e5b3bf004d1cedd2 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Mon, 6 Aug 2018 18:51:37 -0500
Subject: [PATCH 06/18] Use 3.0 version of poison

---
 mix.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index 6f35668..921a28b 100644
--- a/mix.exs
+++ b/mix.exs
@@ -39,7 +39,7 @@ defmodule CloudWatch.Mixfile do
      {:aws, "~> 0.5.0", optional: true},
      {:ex_aws, "~> 2.0"},
      {:httpoison, "~> 0.11.1"},
-     {:poison, "~> 4.0"},
+     {:poison, "~> 3.0"},
      {:credo, "~> 0.4.13", only: :dev},
      {:mock, "~> 0.2.0", only: :test},
      {:ex_doc, ">= 0.0.0", only: :dev}]

From dacabb8d4fb5d814e43073e2ca48bcde7172fb34 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Tue, 7 Aug 2018 07:23:57 -0500
Subject: [PATCH 07/18] Use hackney directly to avoid dependency on httpoison

---
 lib/cloud_watch.ex | 35 ++++++++++++++++++++++++++++-------
 mix.exs            |  1 -
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index a0bab38..ca2bc79 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -188,21 +188,34 @@ defmodule CloudWatch do
   end
 
   defp get_metadata(url) do
-    case HTTPoison.get(url) do
-      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
-        {:ok, body}
+    case :hackney.request(:get, url, [], "", []) do
+      {:ok, 200, _resp_headers, client_ref} ->
+        :hackney.body(client_ref)
       _ ->
         nil
     end
+    # case HTTPoison.get(url) do
+    #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+    #     {:ok, body}
+    #   _ ->
+    #     nil
+    # end
   end
 
   defp get_metadata!(url) do
-    case HTTPoison.get(url) do
-      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+    case :hackney.request(:get, url, [], "", []) do
+      {:ok, 200, _resp_headers, client_ref} ->
+        {:ok, body} = :hackney.body(client_ref)
         body
       _ ->
         nil
     end
+    # case HTTPoison.get(url) do
+    #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+    #     body
+    #   _ ->
+    #     nil
+    # end
   end
 
   defp metadata_endpoint do
@@ -214,12 +227,20 @@ defmodule CloudWatch do
   end
 
   defp metadata_region do
-    case HTTPoison.get("http://169.254.169.254/latest/meta-data/placement/availability-zone") do
-      {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+    url = "http://169.254.169.254/latest/meta-data/placement/availability-zone"
+    case :hackney.request(:get, url, [], "", []) do
+      {:ok, 200, _resp_headers, client_ref} ->
+        {:ok, body} = :hackney.body(client_ref)
         String.slice(body, Range.new(0, -2))
       _ ->
         nil
     end
+    # case HTTPoison.get("http://169.254.169.254/latest/meta-data/placement/availability-zone") do
+    #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
+    #     String.slice(body, Range.new(0, -2))
+    #   _ ->
+    #     nil
+    # end
   end
 
 end
diff --git a/mix.exs b/mix.exs
index 921a28b..bf2cb08 100644
--- a/mix.exs
+++ b/mix.exs
@@ -38,7 +38,6 @@ defmodule CloudWatch.Mixfile do
     [
      {:aws, "~> 0.5.0", optional: true},
      {:ex_aws, "~> 2.0"},
-     {:httpoison, "~> 0.11.1"},
      {:poison, "~> 3.0"},
      {:credo, "~> 0.4.13", only: :dev},
      {:mock, "~> 0.2.0", only: :test},

From 353f96b9fc838032d669217d178ebda4f9fe3e8d Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Tue, 7 Aug 2018 07:38:58 -0500
Subject: [PATCH 08/18] Add explicit hackney dep

---
 mix.exs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mix.exs b/mix.exs
index bf2cb08..0f89724 100644
--- a/mix.exs
+++ b/mix.exs
@@ -39,6 +39,7 @@ defmodule CloudWatch.Mixfile do
      {:aws, "~> 0.5.0", optional: true},
      {:ex_aws, "~> 2.0"},
      {:poison, "~> 3.0"},
+     {:hackney, "~> 1.0"},
      {:credo, "~> 0.4.13", only: :dev},
      {:mock, "~> 0.2.0", only: :test},
      {:ex_doc, ">= 0.0.0", only: :dev}]

From 84aed09f91b505e73ba45d4f630c0d1dfc10449f Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Tue, 7 Aug 2018 07:50:44 -0500
Subject: [PATCH 09/18] Use top level API for Poison

---
 lib/cloud_watch.ex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index ca2bc79..dfc1fbf 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -118,7 +118,7 @@ defmodule CloudWatch do
             state
           {:ok, role} ->
             {:ok, json} = get_metadata("http://169.254.169.254/latest/meta-data/iam/security-credentials/" <> role)
-            creds = Poison.Parser.parse!(json)
+            {:ok, creds} = Poison.decode(json)
             access_key_id = Map.get(creds, "AccessKeyId")
             secret_access_key = Map.get(creds, "SecretAccessKey")
             region = state.region || metadata_region()
@@ -135,7 +135,7 @@ defmodule CloudWatch do
         # https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html
         case get_metadata("http://169.254.170.2" <> uri) do
           {:ok, json} ->
-            creds = Poison.Parser.parse!(json)
+            {:ok, creds} = Poison.decode(json)
             access_key_id = Map.get(creds, "AccessKeyId")
             secret_access_key = Map.get(creds, "SecretAccessKey")
             region = state.region

From 41e65bd51871b30d4e76d445ae908e111d24d5c7 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Tue, 7 Aug 2018 08:34:22 -0500
Subject: [PATCH 10/18] Remove aws deps

---
 mix.exs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mix.exs b/mix.exs
index 0f89724..3c4e54f 100644
--- a/mix.exs
+++ b/mix.exs
@@ -36,8 +36,8 @@ defmodule CloudWatch.Mixfile do
   # Type "mix help deps" for more examples and options
   defp deps do
     [
-     {:aws, "~> 0.5.0", optional: true},
-     {:ex_aws, "~> 2.0"},
+     # {:aws, "~> 0.5.0", optional: true},
+     # {:ex_aws, "~> 2.0"},
      {:poison, "~> 3.0"},
      {:hackney, "~> 1.0"},
      {:credo, "~> 0.4.13", only: :dev},

From db5218aa344ee748aa15cb373144ca68d2d2ed3f Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Tue, 7 Aug 2018 22:36:28 +0000
Subject: [PATCH 11/18] Add deps directly

---
 mix.exs  |  8 ++++----
 mix.lock | 11 ++++++-----
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/mix.exs b/mix.exs
index 3c4e54f..10e79f4 100644
--- a/mix.exs
+++ b/mix.exs
@@ -17,7 +17,7 @@ defmodule CloudWatch.Mixfile do
   #
   # Type "mix help compile.app" for more information
   def application do
-    [applications: [:logger, :hackney]]
+    [extra_applications: [:logger]]
   end
 
   # This makes sure your factory and any other modules in test/support are compiled
@@ -37,9 +37,9 @@ defmodule CloudWatch.Mixfile do
   defp deps do
     [
      # {:aws, "~> 0.5.0", optional: true},
-     # {:ex_aws, "~> 2.0"},
-     {:poison, "~> 3.0"},
-     {:hackney, "~> 1.0"},
+     {:httpoison, "~> 0.11"},
+     {:poison, "~> 3.1"},
+     {:hackney, "~> 1.8"},
      {:credo, "~> 0.4.13", only: :dev},
      {:mock, "~> 0.2.0", only: :test},
      {:ex_doc, ">= 0.0.0", only: :dev}]
diff --git a/mix.lock b/mix.lock
index eea41e7..d48b6dd 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,23 +1,24 @@
 %{
   "aws": {:hex, :aws, "0.5.0", "e3916abd9d1fb4c182cbeac8a964ddeb32de9b20d441b66fba838ade06a4a278", [:mix], [{:httpoison, "~> 0.11.1", [hex: :httpoison, repo: "hexpm", optional: false]}, {:poison, "~> 3.1", [hex: :poison, repo: "hexpm", optional: false]}, {:timex, "~> 3.1", [hex: :timex, repo: "hexpm", optional: false]}], "hexpm"},
   "bunt": {:hex, :bunt, "0.1.6", "5d95a6882f73f3b9969fdfd1953798046664e6f77ec4e486e6fafc7caad97c6f", [:mix], [], "hexpm"},
-  "certifi": {:hex, :certifi, "1.2.1", "c3904f192bd5284e5b13f20db3ceac9626e14eeacfbb492e19583cf0e37b22be", [:rebar3], [], "hexpm"},
+  "certifi": {:hex, :certifi, "2.3.1", "d0f424232390bf47d82da8478022301c561cf6445b5b5fb6a84d49a9e76d2639", [:rebar3], [{:parse_trans, "3.2.0", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
   "combine": {:hex, :combine, "0.9.6", "8d1034a127d4cbf6924c8a5010d3534d958085575fa4d9b878f200d79ac78335", [:mix], [], "hexpm"},
   "credo": {:hex, :credo, "0.4.14", "594a965ae2224997fae9e705e881983911a052c701b05bd3bcf89af44b5f6b45", [:mix], [{:bunt, "~> 0.1.6", [hex: :bunt, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.2.2", "f718159d6b65068e8daeef709ccddae5f7fdc770707d82e7d126f584cd925b74", [:mix], [], "hexpm"},
   "ex_aws": {:hex, :ex_aws, "2.1.0", "b92651527d6c09c479f9013caa9c7331f19cba38a650590d82ebf2c6c16a1d8a", [:mix], [{:configparser_ex, "~> 2.0", [hex: :configparser_ex, repo: "hexpm", optional: true]}, {:hackney, "1.6.3 or 1.6.5 or 1.7.1 or 1.8.6 or ~> 1.9", [hex: :hackney, repo: "hexpm", optional: true]}, {:jsx, "~> 2.8", [hex: :jsx, repo: "hexpm", optional: true]}, {:poison, ">= 1.2.0", [hex: :poison, repo: "hexpm", optional: true]}, {:sweet_xml, "~> 0.6", [hex: :sweet_xml, repo: "hexpm", optional: true]}, {:xml_builder, "~> 0.1.0", [hex: :xml_builder, repo: "hexpm", optional: true]}], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.16.2", "3b3e210ebcd85a7c76b4e73f85c5640c011d2a0b2f06dcdf5acdb2ae904e5084", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}], "hexpm"},
   "gettext": {:hex, :gettext, "0.13.1", "5e0daf4e7636d771c4c71ad5f3f53ba09a9ae5c250e1ab9c42ba9edccc476263", [:mix], [], "hexpm"},
-  "hackney": {:hex, :hackney, "1.8.6", "21a725db3569b3fb11a6af17d5c5f654052ce9624219f1317e8639183de4a423", [:rebar3], [{:certifi, "1.2.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "5.0.2", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.1", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
-  "httpoison": {:hex, :httpoison, "0.11.2", "9e59f17a473ef6948f63c51db07320477bad8ba88cf1df60a3eee01150306665", [:mix], [{:hackney, "~> 1.8.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
-  "idna": {:hex, :idna, "5.0.2", "ac203208ada855d95dc591a764b6e87259cb0e2a364218f215ad662daa8cd6b4", [:rebar3], [{:unicode_util_compat, "0.2.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
+  "hackney": {:hex, :hackney, "1.13.0", "24edc8cd2b28e1c652593833862435c80661834f6c9344e84b6a2255e7aeef03", [:rebar3], [{:certifi, "2.3.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "5.1.2", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.1", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
+  "httpoison": {:hex, :httpoison, "0.13.0", "bfaf44d9f133a6599886720f3937a7699466d23bb0cd7a88b6ba011f53c6f562", [:mix], [{:hackney, "~> 1.8", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
+  "idna": {:hex, :idna, "5.1.2", "e21cb58a09f0228a9e0b95eaa1217f1bcfc31a1aaa6e1fdf2f53a33f7dbd9494", [:rebar3], [{:unicode_util_compat, "0.3.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
   "meck": {:hex, :meck, "0.8.11", "2c39e15ec87d847da6cf69b4a1c4af3fd850ae2a272e719e0e8751a7fe54771f", [:rebar3], [], "hexpm"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
   "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
   "mock": {:hex, :mock, "0.2.1", "bfdba786903e77f9c18772dee472d020ceb8ef000783e737725a4c8f54ad28ec", [:mix], [{:meck, "~> 0.8.2", [hex: :meck, repo: "hexpm", optional: false]}], "hexpm"},
+  "parse_trans": {:hex, :parse_trans, "3.2.0", "2adfa4daf80c14dc36f522cf190eb5c4ee3e28008fc6394397c16f62a26258c2", [:rebar3], [], "hexpm"},
   "poison": {:hex, :poison, "3.1.0", "d9eb636610e096f86f25d9a46f35a9facac35609a7591b3be3326e99a0484665", [:mix], [], "hexpm"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.1", "28a4d65b7f59893bc2c7de786dec1e1555bd742d336043fe644ae956c3497fbe", [:make, :rebar], [], "hexpm"},
   "timex": {:hex, :timex, "3.1.21", "7d1ec0f73c4668bea71f38af6357d75992f356a7e032c69620c5e87ca4b95c66", [:mix], [{:combine, "~> 0.7", [hex: :combine, repo: "hexpm", optional: false]}, {:gettext, "~> 0.10", [hex: :gettext, repo: "hexpm", optional: false]}, {:tzdata, "~> 0.1.8 or ~> 0.5", [hex: :tzdata, repo: "hexpm", optional: false]}], "hexpm"},
   "tzdata": {:hex, :tzdata, "0.5.12", "1c17b68692c6ba5b6ab15db3d64cc8baa0f182043d5ae9d4b6d35d70af76f67b", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
-  "unicode_util_compat": {:hex, :unicode_util_compat, "0.2.0", "dbbccf6781821b1c0701845eaf966c9b6d83d7c3bfc65ca2b78b88b8678bfa35", [:rebar3], [], "hexpm"},
+  "unicode_util_compat": {:hex, :unicode_util_compat, "0.3.1", "a1f612a7b512638634a603c8f401892afbf99b8ce93a45041f8aaca99cadb85e", [:rebar3], [], "hexpm"},
 }

From 54f494c32bd67ba81a7eaeed76b0141cadd13320 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Tue, 7 Aug 2018 22:39:14 +0000
Subject: [PATCH 12/18] Debugging

---
 lib/cloud_watch.ex | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index dfc1fbf..24ec454 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -9,7 +9,10 @@ defmodule CloudWatch do
   alias CloudWatch.InputLogEvent
   alias CloudWatch.AwsProxy
 
-  def init(_args) do
+  @spec init(module()) :: {:ok, term()} | {:error, term()}
+  def init(__MODULE__) do
+    {:ok, _} = Application.ensure_all_started(:hackney)
+
     state = configure([])
 
     # If AWS keys are not defined statically, get them from the instance metadata.
@@ -28,6 +31,7 @@ defmodule CloudWatch do
   end
 
   def handle_call({:configure, opts}, _) do
+    Application.put_env(:logger, __MODULE__, opts)
     {:ok, :ok, configure(opts)}
   end
 
@@ -83,14 +87,15 @@ defmodule CloudWatch do
   end
 
   @spec configure(Keyword.t) :: Map.t
-  defp configure(opts) do
-    opts = Keyword.merge(Application.get_env(:logger, CloudWatch, []), opts)
+  def configure(opts) do
+    env = Application.get_env(:logger, __MODULE__, [])
+    opts = Keyword.merge(env, opts)
 
     state = %{
       access_key_id: opts[:access_key_id],
       secret_access_key: opts[:secret_access_key],
-      region: opts[:region] || metadata_region(),
-      endpoint: opts[:endpoint] || metadata_endpoint(),
+      region: opts[:region],
+      endpoint: opts[:endpoint],
       client: nil,
       buffer: [], buffer_size: 0,
       level: opts[:level] || @default_level,
@@ -109,7 +114,7 @@ defmodule CloudWatch do
     end
   end
 
-  defp configure_aws(state) do
+  def configure_aws(state) do
     case System.get_env("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI") do
       nil ->
         # https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html
@@ -187,7 +192,7 @@ defmodule CloudWatch do
     end
   end
 
-  defp get_metadata(url) do
+  def get_metadata(url) do
     case :hackney.request(:get, url, [], "", []) do
       {:ok, 200, _resp_headers, client_ref} ->
         :hackney.body(client_ref)
@@ -202,7 +207,7 @@ defmodule CloudWatch do
     # end
   end
 
-  defp get_metadata!(url) do
+  def get_metadata!(url) do
     case :hackney.request(:get, url, [], "", []) do
       {:ok, 200, _resp_headers, client_ref} ->
         {:ok, body} = :hackney.body(client_ref)
@@ -218,15 +223,15 @@ defmodule CloudWatch do
     # end
   end
 
-  defp metadata_endpoint do
+  def metadata_endpoint do
     get_metadata!("http://169.254.169.254/latest/meta-data/services/domain")
   end
 
-  defp metadata_instance_id do
+  def metadata_instance_id do
     get_metadata!("http://169.254.169.254/latest/meta-data/instance-id")
   end
 
-  defp metadata_region do
+  def metadata_region do
     url = "http://169.254.169.254/latest/meta-data/placement/availability-zone"
     case :hackney.request(:get, url, [], "", []) do
       {:ok, 200, _resp_headers, client_ref} ->
@@ -235,7 +240,7 @@ defmodule CloudWatch do
       _ ->
         nil
     end
-    # case HTTPoison.get("http://169.254.169.254/latest/meta-data/placement/availability-zone") do
+    # case HTTPoison.get(url) do
     #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
     #     String.slice(body, Range.new(0, -2))
     #   _ ->

From 49e8f64e6676e112a12803c0ddd62d9be58423f2 Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Wed, 8 Aug 2018 14:18:29 +0000
Subject: [PATCH 13/18] Update location of aws-elixir

---
 lib/cloud_watch/aws_proxy.ex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/cloud_watch/aws_proxy.ex b/lib/cloud_watch/aws_proxy.ex
index a80482f..12b72a6 100644
--- a/lib/cloud_watch/aws_proxy.ex
+++ b/lib/cloud_watch/aws_proxy.ex
@@ -8,7 +8,7 @@ defmodule CloudWatch.AwsProxy do
   cond do
     Code.ensure_loaded?(AWS) ->
       # AWS CloudWatch Logs implemented using aws-elixir
-      # See https://github.com/jkakar/aws-elixir
+      # https://github.com/aws-beam/aws-elixir
       #
       # AWS credentials are configured in CloudWatch
       def client(access_key_id, secret_access_key, region, endpoint) do

From 341dee00c3a4c56fb7a2fb51dc73baaf7444b0fa Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Wed, 8 Aug 2018 14:18:41 +0000
Subject: [PATCH 14/18] Formatting

---
 lib/cloud_watch/input_log_event.ex | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/cloud_watch/input_log_event.ex b/lib/cloud_watch/input_log_event.ex
index 877db69..71bc79c 100644
--- a/lib/cloud_watch/input_log_event.ex
+++ b/lib/cloud_watch/input_log_event.ex
@@ -10,6 +10,7 @@ defmodule CloudWatch.InputLogEvent do
       |> Kernel.-(@epoch)
       |> Kernel.*(1000)
       |> Kernel.+(milliseconds)
+
       %{message: message, timestamp: timestamp}
       |> Poison.Encoder.encode(options)
       |> IO.chardata_to_string

From b5cfa4de7c1a197452febfefd4e542000a028c5f Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Wed, 8 Aug 2018 14:22:33 +0000
Subject: [PATCH 15/18] Save config to env; crash if group/stream create fails;
 reduce piping

---
 lib/cloud_watch.ex | 57 +++++++++++++++++++++++-----------------------
 1 file changed, 29 insertions(+), 28 deletions(-)

diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index 24ec454..b56f633 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -13,7 +13,8 @@ defmodule CloudWatch do
   def init(__MODULE__) do
     {:ok, _} = Application.ensure_all_started(:hackney)
 
-    state = configure([])
+    env = Application.get_env(:logger, __MODULE__, [])
+    state = configure(env)
 
     # If AWS keys are not defined statically, get them from the instance metadata.
     # This may fail while the instance is starting up, so retry quickly.
@@ -44,10 +45,13 @@ defmodule CloudWatch do
       :lt -> {:ok, state}
       _ ->
         %{buffer: buffer, buffer_size: buffer_size} = state
+
         message = state.format
         |> Logger.Formatter.format(level, msg, ts, md)
         |> IO.chardata_to_string
+
         buffer = List.insert_at(buffer, -1, %InputLogEvent{message: message, timestamp: ts})
+
         state
         |> Map.merge(%{buffer: buffer, buffer_size: buffer_size + byte_size(message) + 26})
         |> flush()
@@ -88,9 +92,6 @@ defmodule CloudWatch do
 
   @spec configure(Keyword.t) :: Map.t
   def configure(opts) do
-    env = Application.get_env(:logger, __MODULE__, [])
-    opts = Keyword.merge(env, opts)
-
     state = %{
       access_key_id: opts[:access_key_id],
       secret_access_key: opts[:secret_access_key],
@@ -165,30 +166,30 @@ defmodule CloudWatch do
   defp flush(%{client: nil} = state, _opts), do: {:ok, state}
 
   defp flush(state, opts) do
-    case AwsProxy.put_log_events(state.client, %{logEvents: Enum.sort_by(state.buffer, &(&1.timestamp)),
-      logGroupName: state.log_group_name, logStreamName: state.log_stream_name, sequenceToken: state.sequence_token}) do
-        {:ok, %{"nextSequenceToken" => next_sequence_token}, _} ->
-          {:ok, Map.merge(state, %{buffer: [], buffer_size: 0, sequence_token: next_sequence_token})}
-        {:error, {"DataAlreadyAcceptedException", "The given batch of log events has already been accepted. The next batch can be sent with sequenceToken: " <> next_sequence_token}} ->
-          state
-          |> Map.put(:sequence_token, next_sequence_token)
-          |> flush(opts)
-        {:error, {"InvalidSequenceTokenException", "The given sequenceToken is invalid. The next expected sequenceToken is: " <> next_sequence_token}} ->
-          state
-          |> Map.put(:sequence_token, next_sequence_token)
-          |> flush(opts)
-        {:error, {"ResourceNotFoundException", "The specified log group does not exist."}} ->
-          AwsProxy.create_log_group(state.client, %{logGroupName: state.log_group_name})
-          AwsProxy.create_log_stream(state.client, %{logGroupName: state.log_group_name,
-            logStreamName: state.log_stream_name})
-          flush(state, opts)
-        {:error, {"ResourceNotFoundException", "The specified log stream does not exist."}} ->
-          AwsProxy.create_log_stream(state.client, %{logGroupName: state.log_group_name,
-            logStreamName: state.log_stream_name})
-          flush(state, opts)
-        {:error, %HTTPoison.Error{id: nil, reason: reason}} when reason in [:closed, :connect_timeout, :timeout] ->
-          state
-          |> flush(opts)
+    events = %{logEvents: Enum.sort_by(state.buffer, &(&1.timestamp)),
+      logGroupName: state.log_group_name, logStreamName: state.log_stream_name,
+      sequenceToken: state.sequence_token}
+
+    case AwsProxy.put_log_events(state.client, events) do
+      {:ok, %{"nextSequenceToken" => next_sequence_token}, _} ->
+        {:ok, %{state | buffer: [], buffer_size: 0, sequence_token: next_sequence_token}}
+      {:error, {"DataAlreadyAcceptedException",
+          "The given batch of log events has already been accepted. The next batch can be sent with sequenceToken: " <> next_sequence_token}} ->
+        flush(%{state | sequence_token: next_sequence_token}, opts)
+      {:error, {"InvalidSequenceTokenException",
+          "The given sequenceToken is invalid. The next expected sequenceToken is: " <> next_sequence_token}} ->
+        flush(%{state | sequence_token: next_sequence_token}, opts)
+      {:error, {"ResourceNotFoundException", "The specified log group does not exist."}} ->
+        {:ok, _, _} = AwsProxy.create_log_group(state.client, %{logGroupName: state.log_group_name})
+        {:ok, _, _} = AwsProxy.create_log_stream(state.client, %{logGroupName: state.log_group_name,
+          logStreamName: state.log_stream_name})
+        flush(state, opts)
+      {:error, {"ResourceNotFoundException", "The specified log stream does not exist."}} ->
+        {:ok, _, _} = AwsProxy.create_log_stream(state.client, %{logGroupName: state.log_group_name,
+          logStreamName: state.log_stream_name})
+        flush(state, opts)
+      {:error, %HTTPoison.Error{id: nil, reason: reason}} when reason in [:closed, :connect_timeout, :timeout] ->
+        flush(state, opts)
     end
   end
 

From 7a777d846760bbb3c8689b2cb88fb640818effdd Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Wed, 8 Aug 2018 15:57:38 +0000
Subject: [PATCH 16/18] Cleanup and commenting

---
 lib/cloud_watch.ex | 28 ++++++----------------------
 1 file changed, 6 insertions(+), 22 deletions(-)

diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index b56f633..d3a650d 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -42,7 +42,8 @@ defmodule CloudWatch do
 
   def handle_event({level, _gl, {Logger, msg, ts, md}}, state) do
     case Logger.compare_levels(level, state.level) do
-      :lt -> {:ok, state}
+      :lt ->
+        {:ok, state}
       _ ->
         %{buffer: buffer, buffer_size: buffer_size} = state
 
@@ -52,9 +53,7 @@ defmodule CloudWatch do
 
         buffer = List.insert_at(buffer, -1, %InputLogEvent{message: message, timestamp: ts})
 
-        state
-        |> Map.merge(%{buffer: buffer, buffer_size: buffer_size + byte_size(message) + 26})
-        |> flush()
+        flush(%{state | buffer: buffer, buffer_size: buffer_size + byte_size(message) + 26})
     end
   end
 
@@ -109,6 +108,7 @@ defmodule CloudWatch do
     }
 
     if state.access_key_id do
+      # Static AWS config
       %{state | client: AwsProxy.client(state.access_key_id, state.secret_access_key, state.region, state.endpoint)}
     else
       configure_aws(state)
@@ -139,6 +139,7 @@ defmodule CloudWatch do
         end
       uri ->
         # https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html
+        # This is untested
         case get_metadata("http://169.254.170.2" <> uri) do
           {:ok, json} ->
             {:ok, creds} = Poison.decode(json)
@@ -163,6 +164,7 @@ defmodule CloudWatch do
 
   defp flush(%{buffer: []} = state, _opts), do: {:ok, state}
 
+  # Client not configured yet
   defp flush(%{client: nil} = state, _opts), do: {:ok, state}
 
   defp flush(state, opts) do
@@ -200,12 +202,6 @@ defmodule CloudWatch do
       _ ->
         nil
     end
-    # case HTTPoison.get(url) do
-    #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
-    #     {:ok, body}
-    #   _ ->
-    #     nil
-    # end
   end
 
   def get_metadata!(url) do
@@ -216,12 +212,6 @@ defmodule CloudWatch do
       _ ->
         nil
     end
-    # case HTTPoison.get(url) do
-    #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
-    #     body
-    #   _ ->
-    #     nil
-    # end
   end
 
   def metadata_endpoint do
@@ -241,12 +231,6 @@ defmodule CloudWatch do
       _ ->
         nil
     end
-    # case HTTPoison.get(url) do
-    #   {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
-    #     String.slice(body, Range.new(0, -2))
-    #   _ ->
-    #     nil
-    # end
   end
 
 end

From 2709093ad5f7093ad0b67af427af0687cf86b41f Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Wed, 8 Aug 2018 18:51:24 +0000
Subject: [PATCH 17/18] Update deps

---
 mix.exs  |  2 +-
 mix.lock | 29 +++++++++++++++--------------
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/mix.exs b/mix.exs
index 10e79f4..1cb37e1 100644
--- a/mix.exs
+++ b/mix.exs
@@ -36,7 +36,7 @@ defmodule CloudWatch.Mixfile do
   # Type "mix help deps" for more examples and options
   defp deps do
     [
-     # {:aws, "~> 0.5.0", optional: true},
+     {:aws, "~> 0.5.0", optional: true},
      {:httpoison, "~> 0.11"},
      {:poison, "~> 3.1"},
      {:hackney, "~> 1.8"},
diff --git a/mix.lock b/mix.lock
index d48b6dd..7bbeb31 100644
--- a/mix.lock
+++ b/mix.lock
@@ -1,24 +1,25 @@
 %{
   "aws": {:hex, :aws, "0.5.0", "e3916abd9d1fb4c182cbeac8a964ddeb32de9b20d441b66fba838ade06a4a278", [:mix], [{:httpoison, "~> 0.11.1", [hex: :httpoison, repo: "hexpm", optional: false]}, {:poison, "~> 3.1", [hex: :poison, repo: "hexpm", optional: false]}, {:timex, "~> 3.1", [hex: :timex, repo: "hexpm", optional: false]}], "hexpm"},
   "bunt": {:hex, :bunt, "0.1.6", "5d95a6882f73f3b9969fdfd1953798046664e6f77ec4e486e6fafc7caad97c6f", [:mix], [], "hexpm"},
-  "certifi": {:hex, :certifi, "2.3.1", "d0f424232390bf47d82da8478022301c561cf6445b5b5fb6a84d49a9e76d2639", [:rebar3], [{:parse_trans, "3.2.0", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
-  "combine": {:hex, :combine, "0.9.6", "8d1034a127d4cbf6924c8a5010d3534d958085575fa4d9b878f200d79ac78335", [:mix], [], "hexpm"},
+  "certifi": {:hex, :certifi, "1.2.1", "c3904f192bd5284e5b13f20db3ceac9626e14eeacfbb492e19583cf0e37b22be", [:rebar3], [], "hexpm"},
+  "combine": {:hex, :combine, "0.10.0", "eff8224eeb56498a2af13011d142c5e7997a80c8f5b97c499f84c841032e429f", [:mix], [], "hexpm"},
   "credo": {:hex, :credo, "0.4.14", "594a965ae2224997fae9e705e881983911a052c701b05bd3bcf89af44b5f6b45", [:mix], [{:bunt, "~> 0.1.6", [hex: :bunt, repo: "hexpm", optional: false]}], "hexpm"},
-  "earmark": {:hex, :earmark, "1.2.2", "f718159d6b65068e8daeef709ccddae5f7fdc770707d82e7d126f584cd925b74", [:mix], [], "hexpm"},
-  "ex_aws": {:hex, :ex_aws, "2.1.0", "b92651527d6c09c479f9013caa9c7331f19cba38a650590d82ebf2c6c16a1d8a", [:mix], [{:configparser_ex, "~> 2.0", [hex: :configparser_ex, repo: "hexpm", optional: true]}, {:hackney, "1.6.3 or 1.6.5 or 1.7.1 or 1.8.6 or ~> 1.9", [hex: :hackney, repo: "hexpm", optional: true]}, {:jsx, "~> 2.8", [hex: :jsx, repo: "hexpm", optional: true]}, {:poison, ">= 1.2.0", [hex: :poison, repo: "hexpm", optional: true]}, {:sweet_xml, "~> 0.6", [hex: :sweet_xml, repo: "hexpm", optional: true]}, {:xml_builder, "~> 0.1.0", [hex: :xml_builder, repo: "hexpm", optional: true]}], "hexpm"},
-  "ex_doc": {:hex, :ex_doc, "0.16.2", "3b3e210ebcd85a7c76b4e73f85c5640c011d2a0b2f06dcdf5acdb2ae904e5084", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}], "hexpm"},
-  "gettext": {:hex, :gettext, "0.13.1", "5e0daf4e7636d771c4c71ad5f3f53ba09a9ae5c250e1ab9c42ba9edccc476263", [:mix], [], "hexpm"},
-  "hackney": {:hex, :hackney, "1.13.0", "24edc8cd2b28e1c652593833862435c80661834f6c9344e84b6a2255e7aeef03", [:rebar3], [{:certifi, "2.3.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "5.1.2", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.1", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
-  "httpoison": {:hex, :httpoison, "0.13.0", "bfaf44d9f133a6599886720f3937a7699466d23bb0cd7a88b6ba011f53c6f562", [:mix], [{:hackney, "~> 1.8", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
-  "idna": {:hex, :idna, "5.1.2", "e21cb58a09f0228a9e0b95eaa1217f1bcfc31a1aaa6e1fdf2f53a33f7dbd9494", [:rebar3], [{:unicode_util_compat, "0.3.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
-  "meck": {:hex, :meck, "0.8.11", "2c39e15ec87d847da6cf69b4a1c4af3fd850ae2a272e719e0e8751a7fe54771f", [:rebar3], [], "hexpm"},
+  "earmark": {:hex, :earmark, "1.2.5", "4d21980d5d2862a2e13ec3c49ad9ad783ffc7ca5769cf6ff891a4553fbaae761", [:mix], [], "hexpm"},
+  "ex_doc": {:hex, :ex_doc, "0.19.1", "519bb9c19526ca51d326c060cb1778d4a9056b190086a8c6c115828eaccea6cf", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.7", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
+  "gettext": {:hex, :gettext, "0.15.0", "40a2b8ce33a80ced7727e36768499fc9286881c43ebafccae6bab731e2b2b8ce", [:mix], [], "hexpm"},
+  "hackney": {:hex, :hackney, "1.8.6", "21a725db3569b3fb11a6af17d5c5f654052ce9624219f1317e8639183de4a423", [:rebar3], [{:certifi, "1.2.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "5.0.2", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.1", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
+  "httpoison": {:hex, :httpoison, "0.11.2", "9e59f17a473ef6948f63c51db07320477bad8ba88cf1df60a3eee01150306665", [:mix], [{:hackney, "~> 1.8.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
+  "idna": {:hex, :idna, "5.0.2", "ac203208ada855d95dc591a764b6e87259cb0e2a364218f215ad662daa8cd6b4", [:rebar3], [{:unicode_util_compat, "0.2.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
+  "makeup": {:hex, :makeup, "0.5.1", "966c5c2296da272d42f1de178c1d135e432662eca795d6dc12e5e8787514edf7", [:mix], [{:nimble_parsec, "~> 0.2.2", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.8.0", "1204a2f5b4f181775a0e456154830524cf2207cf4f9112215c05e0b76e4eca8b", [:mix], [{:makeup, "~> 0.5.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 0.2.2", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
+  "meck": {:hex, :meck, "0.8.12", "1f7b1a9f5d12c511848fec26bbefd09a21e1432eadb8982d9a8aceb9891a3cf2", [:rebar3], [], "hexpm"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
   "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
   "mock": {:hex, :mock, "0.2.1", "bfdba786903e77f9c18772dee472d020ceb8ef000783e737725a4c8f54ad28ec", [:mix], [{:meck, "~> 0.8.2", [hex: :meck, repo: "hexpm", optional: false]}], "hexpm"},
-  "parse_trans": {:hex, :parse_trans, "3.2.0", "2adfa4daf80c14dc36f522cf190eb5c4ee3e28008fc6394397c16f62a26258c2", [:rebar3], [], "hexpm"},
+  "nimble_parsec": {:hex, :nimble_parsec, "0.2.2", "d526b23bdceb04c7ad15b33c57c4526bf5f50aaa70c7c141b4b4624555c68259", [:mix], [], "hexpm"},
   "poison": {:hex, :poison, "3.1.0", "d9eb636610e096f86f25d9a46f35a9facac35609a7591b3be3326e99a0484665", [:mix], [], "hexpm"},
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.1", "28a4d65b7f59893bc2c7de786dec1e1555bd742d336043fe644ae956c3497fbe", [:make, :rebar], [], "hexpm"},
-  "timex": {:hex, :timex, "3.1.21", "7d1ec0f73c4668bea71f38af6357d75992f356a7e032c69620c5e87ca4b95c66", [:mix], [{:combine, "~> 0.7", [hex: :combine, repo: "hexpm", optional: false]}, {:gettext, "~> 0.10", [hex: :gettext, repo: "hexpm", optional: false]}, {:tzdata, "~> 0.1.8 or ~> 0.5", [hex: :tzdata, repo: "hexpm", optional: false]}], "hexpm"},
-  "tzdata": {:hex, :tzdata, "0.5.12", "1c17b68692c6ba5b6ab15db3d64cc8baa0f182043d5ae9d4b6d35d70af76f67b", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
-  "unicode_util_compat": {:hex, :unicode_util_compat, "0.3.1", "a1f612a7b512638634a603c8f401892afbf99b8ce93a45041f8aaca99cadb85e", [:rebar3], [], "hexpm"},
+  "timex": {:hex, :timex, "3.3.0", "e0695aa0ddb37d460d93a2db34d332c2c95a40c27edf22fbfea22eb8910a9c8d", [:mix], [{:combine, "~> 0.10", [hex: :combine, repo: "hexpm", optional: false]}, {:gettext, "~> 0.10", [hex: :gettext, repo: "hexpm", optional: false]}, {:tzdata, "~> 0.1.8 or ~> 0.5", [hex: :tzdata, repo: "hexpm", optional: false]}], "hexpm"},
+  "tzdata": {:hex, :tzdata, "0.5.17", "50793e3d85af49736701da1a040c415c97dc1caf6464112fd9bd18f425d3053b", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
+  "unicode_util_compat": {:hex, :unicode_util_compat, "0.2.0", "dbbccf6781821b1c0701845eaf966c9b6d83d7c3bfc65ca2b78b88b8678bfa35", [:rebar3], [], "hexpm"},
 }

From c0147eac0ef1bdf5433cddd95c4b98dc98dbd09f Mon Sep 17 00:00:00 2001
From: Jake Morrison <jake@cogini.com>
Date: Wed, 8 Aug 2018 19:17:06 +0000
Subject: [PATCH 18/18] Doc

---
 lib/cloud_watch.ex | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/cloud_watch.ex b/lib/cloud_watch.ex
index d3a650d..9e8192b 100644
--- a/lib/cloud_watch.ex
+++ b/lib/cloud_watch.ex
@@ -11,6 +11,8 @@ defmodule CloudWatch do
 
   @spec init(module()) :: {:ok, term()} | {:error, term()}
   def init(__MODULE__) do
+    # Because this is a plugin to Logger, we can't rely on application
+    # dependencies to be started before this is called
     {:ok, _} = Application.ensure_all_started(:hackney)
 
     env = Application.get_env(:logger, __MODULE__, [])