Add AWS Lambda support (#1127)

This adds the lambda-web crate to adapt the actix App to speak to Lambda
by way of the lambda_runtime crate.

AWS Lambda has native support for scripting languages to
execute a function directly; compiled languages must embed a runtime to
fetch incoming events from Lambda and post the responses. This detects
the environment variables to start up in Lambda mode instead of the
normal HTTP server, and is added as an optional feature.

Lambda has five (!) distinct ways of routing HTTP requests to a
function; this supports some of them. (Specifically, the most obvious
way to do this is with a Function URL, which is newest and simplest, and
perhaps with CloudFront, which speaks to the Function URL and not Lambda
directly.)

The error handling could probably be refined, I was just trying to get
this to compile.

(Supported: API Gateway HTTP API with payload format version 2.0; API
Gateway REST API; Lambda function URLs / Not supported: API Gateway HTTP
API with payload format version 1.0; Application Load Balancer)

Necessary for #1102 to be able to run the released packages directly,
and only having to configure the appropriate environment.

---------

Co-authored-by: Yuri Astrakhan <[email protected]>

.dockerignore

@@ -23,3 +23,4 @@ pg_data/
 config.yml
 tests/output/
 tmp/
+.aws-sam/

.github/files/lambda-function/Makefile

@@ -0,0 +1,2 @@
+build-MartinFunction:
+	cp -a . $(ARTIFACTS_DIR)

.github/files/lambda-function/config.yaml

@@ -0,0 +1,3 @@
+pmtiles:
+  sources:
+    webp2: ./webp2.pmtiles

.github/files/lambda-layer/bootstrap

@@ -0,0 +1,3 @@
+#!/bin/sh
+set -eu
+exec martin -c "${_HANDLER}"

.github/files/lambda.yaml

@@ -0,0 +1,19 @@
+# This is a minimal AWS SAM template sufficient to invoke the handler
+# in the CI environment. It probably hasn't been tested for actual
+# deployments.
+
+AWSTemplateFormatVersion: 2010-09-09
+Transform: 'AWS::Serverless-2016-10-31'
+Resources:
+  MartinLayer:
+    Type: 'AWS::Serverless::LayerVersion'
+    Properties:
+      ContentUri: lambda-layer/
+  MartinFunction:
+    Type: 'AWS::Serverless::Function'
+    Properties:
+      Runtime: provided.al2023
+      Layers:
+        - Ref: MartinLayer
+      CodeUri: lambda-function/
+      Handler: config.yaml

.github/workflows/ci.yml

@@ -132,6 +132,10 @@ jobs:
         with:
           install: true
           platforms: linux/amd64,linux/arm64
+      - name: Set up AWS SAM
+        uses: aws-actions/setup-sam@v2
+        with:
+          use-installer: true
 
       - name: Build targets
         run: |
@@ -177,6 +181,7 @@ jobs:
           load: true
           tags: ${{ github.repository }}:linux-arm64
           platforms: linux/arm64
+
       - name: Test linux/arm64 Docker image
         run: |
           PLATFORM=linux/arm64
@@ -288,6 +293,22 @@ jobs:
           name: build-${{ matrix.target }}
           path: target_releases/*
 
+  test-aws-lambda:
+    name: Test AWS Lambda
+    runs-on: ubuntu-latest
+    needs: [ build ]
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Download build artifact cross-build
+        uses: actions/download-artifact@v3
+        with:
+          name: cross-build
+      - run: tests/test-aws-lambda.sh
+        env:
+          MARTIN_BIN: x86_64-unknown-linux-musl/martin
+
+
   test-multi-os:
     name: Test on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}

.gitignore

@@ -11,3 +11,4 @@ pg_data/
 config.yml
 tests/output/
 tmp/
+.aws-sam/

Cargo.toml

@@ -47,6 +47,7 @@ indoc = "2"
 insta = "1"
 itertools = "0.12"
 json-patch = "1.2"
+lambda-web = { version = "0.2.1", features = ["actix4"] }
 log = "0.4"
 martin-tile-utils = { path = "./martin-tile-utils", version = "0.4.0" }
 mbtiles = { path = "./mbtiles", version = "0.9.0" }

docs/src/SUMMARY.md

@@ -7,6 +7,7 @@
   - [Running with Docker](run-with-docker.md)
   - [Running with Docker Compose](run-with-docker-compose.md)
   - [Running with NGINX](run-with-nginx.md)
+  - [Running in AWS Lambda](run-with-lambda.md)
   - [Troubleshooting](troubleshooting.md)
 - [Configuration File](config-file.md)
   - [PostgreSQL Connections](pg-connections.md)

docs/src/env-vars.md

@@ -9,3 +9,4 @@ You can also configure Martin using environment variables, but only if the confi
 | `PGSSLCERT` <br/> `ssl_cert`             | `./postgresql.crt`                   | A file with a client SSL certificate. [docs](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-SSLCERT)                                                                             |
 | `PGSSLKEY` <br/> `ssl_key`               | `./postgresql.key`                   | A file with the key for the client SSL certificate. [docs](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-SSLKEY)                                                                |
 | `PGSSLROOTCERT` <br/> `ssl_root_cert`    | `./root.crt`                         | A file with trusted root certificate(s). The file should contain a sequence of PEM-formatted CA certificates. [docs](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNECT-SSLROOTCERT) |
+| `AWS_LAMBDA_RUNTIME_API`                 |                                      | If defined, connect to AWS Lambda to handle requests. The regular HTTP server is not used. See [Running in AWS Lambda](run-with-lambda.md)                                                                 |