added option 'ignore_errors' to also return failed REST calls

docs/index.asciidoc

@@ -52,6 +52,7 @@ There are also multiple configuration options related to the HTTP connectivity:
 | <<plugins-{type}s-{plugin}-connect_timeout>> |<<number,number>>|No
 | <<plugins-{type}s-{plugin}-cookies>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-follow_redirects>> |<<boolean,boolean>>|No
+| <<plugins-{type}s-{plugin}-ignore_errors>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-keepalive>> |<<boolean,boolean>>|No
 | <<plugins-{type}s-{plugin}-keystore>> |a valid filesystem path|No
 | <<plugins-{type}s-{plugin}-keystore_password>> |<<password,password>>|No
@@ -202,6 +203,15 @@ across requests as a normal web browser would. Enabled by default
 
 Should redirects be followed? Defaults to `true`
 
+[id="plugins-{type}s-{plugin}-ignore_errors"]
+===== `ignore_errors`
+
+  * Value type is <<boolean,boolean>>
+  * Default value is `false`
+
+Set to `true` if you want to also process failed requests. Keep in mind that
+the filter will always succeed, unless there is an exception.
+
 [id="plugins-{type}s-{plugin}-keepalive"]
 ===== `keepalive`
 

lib/logstash/filters/http.rb

@@ -12,14 +12,15 @@ class LogStash::Filters::Http < LogStash::Filters::Base
 
   config_name 'http'
 
-  VALID_VERBS = ['GET', 'HEAD', 'PATCH', 'DELETE', 'POST']
+  VALID_VERBS = ['GET', 'HEAD', 'PATCH', 'DELETE', 'POST', 'PUT']
 
   config :url, :validate => :string, :required => true
   config :verb, :validate => VALID_VERBS, :required => false, :default => 'GET'
   config :headers, :validate => :hash, :required => false, :default => {}
   config :query, :validate => :hash, :required => false, :default => {}
   config :body, :required => false
   config :body_format, :validate => ['text', 'json'], :default => "text"
+  config :ignore_errors, :validate => :boolean, :default => false
 
   config :target_body, :validate => :string, :default => "body"
   config :target_headers, :validate => :string, :default => "headers"
@@ -65,13 +66,13 @@ def filter(event)
                     :url => url_for_event, :body => body_sprintfed,
                     :client_error => client_error.message)
       @tag_on_request_failure.each { |tag| event.tag(tag) }
-    elsif !code.between?(200, 299)
+    elsif !code.between?(200, 299) and !ignore_errors
       @logger.error('error during HTTP request',
                     :url => url_for_event, :code => code,
                     :response => response_body)
       @tag_on_request_failure.each { |tag| event.tag(tag) }
     else
-      @logger.debug? && @logger.debug('success received',
+      @logger.debug? && @logger.debug('received response',
                                       :code => code, :body => response_body)
       process_response(response_body, response_headers, event)
       filter_matched(event)

spec/filters/http_spec.rb

@@ -68,6 +68,26 @@
       expect(event.get('tags')).to include('_httprequestfailure')
     end
   end
+  context 'when request returns 404 but ignores errors' do
+    before(:each) { subject.register }
+    let(:config) do
+      {
+        'url' => 'http://httpstat.us/404',
+        'target_body' => 'rest',
+        'ignore_errors' => true
+      }
+    end
+    let(:response) { [404, {}, "request failed"] }
+
+    before(:each) do
+      allow(subject).to receive(:request_http).and_return(response)
+      subject.filter(event)
+    end
+
+    it "fetches event and returns body" do
+      expect(event.get('rest')).to eq("request failed")
+    end
+  end
   describe "headers" do
     before(:each) { subject.register }
     let(:response) { [200, {}, "Bom dia"] }