feat: 🎸 specify environment variables at build time

use variable `build_environment_variables` to specify environment
variables to be used by the build process at build time in the worker
lambda

Author: jamespamplin

README.md

@@ -86,6 +86,7 @@ module "my_lambda" {
 | Name                                                                                                                  | Description                                                                                                                                                                          | Type                                                                                    | Default                                             | Required |
 | --------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------- | --------------------------------------------------- | :------: |
 | <a name="input_build_commands"></a> [build_commands](#input_build_commands)                                           | Commands to run remotely on the worker lambda during build phase, in the directory root of `${var.package_source_path}`                                                              | `list(string)`                                                                          | <pre>[<br> "npm ci",<br> "npm run build"<br>]</pre> |    no    |
+| <a name="input_build_environment_variables"></a> [build_environment_variables](#input_build_environment_variables)    | A map that defines environment variables to use in the build process while building the lambda in the worker.                                                                        | `map(string)`                                                                           | `{}`                                                |    no    |
 | <a name="input_cloudwatch_logs_enable"></a> [cloudwatch_logs_enable](#input_cloudwatch_logs_enable)                   | Enable logging to cloudwatch logs for the built lambda                                                                                                                               | `bool`                                                                                  | `true`                                              |    no    |
 | <a name="input_cloudwatch_logs_retention"></a> [cloudwatch_logs_retention](#input_cloudwatch_logs_retention)          | Log retention in days                                                                                                                                                                | `number`                                                                                | `7`                                                 |    no    |
 | <a name="input_lambda_environment_variables"></a> [lambda_environment_variables](#input_lambda_environment_variables) | A map that defines environment variables for the built lambda.                                                                                                                       | `map(string)`                                                                           | `{}`                                                |    no    |

integration-test/lambda_source/package.json

@@ -11,6 +11,7 @@
   },
   "main": "main.js",
   "scripts": {
+    "prebuild": "mkdir -p dist && echo $RUNNER > dist/build.txt",
     "build": "tsc && cp *.json ./dist"
   },
   "devDependencies": {

integration-test/main.tf

@@ -60,7 +60,11 @@ module "integration_test" {
     "npm run build"
   ]
 
-  package_target_include = ["*.js", "*.json"]
+  build_environment_variables = {
+    RUNNER = "integration_test"
+  }
+
+  package_target_include = ["*.js", "*.json", "build.txt"]
   package_target_exclude = ["tsconfig.json", "*-lock.json"]
 }
 

modules/lambda-worker/sources/worker/main.js

@@ -25,6 +25,7 @@ const eventSource = "io.sellalong.lambda-cd-worker"
 /**
  * @typedef {object} WorkerBuildEvent
  * @property {string[]} commands
+ * @property {Record<string, string>} environment
  * @property {WorkerBuildEventS3} s3
  */
 
@@ -45,6 +46,7 @@ function isBuildEvent(event) {
     e.source === eventSource &&
     typeof e.detail === "object" &&
     Array.isArray(e.detail.commands) &&
+    typeof e.detail.environment === "object" &&
     typeof e.detail.s3 === "object" &&
     typeof e.detail.s3.sources === "object" &&
     typeof e.detail.s3.sources.bucket === "string" &&
@@ -280,6 +282,8 @@ module.exports.handler = async function handler(event) {
 
           // Prioritise additional node cli tools when added as a layer(s)
           PATH: `/opt/nodejs/node_modules/.bin:${process.env.PATH}`,
+
+          ...event.detail.environment,
         },
       })
 

variables.tf

@@ -4,6 +4,11 @@ variable "build_commands" {
   default     = ["npm ci", "npm run build"]
 }
 
+variable "build_environment_variables" {
+  description = "A map that defines environment variables to use in the build process while building the lambda in the worker."
+  type        = map(string)
+  default     = {}
+}
 
 variable "cloudwatch_logs_enable" {
   description = "Enable logging to cloudwatch logs for the built lambda"

worker-invoke.tf

@@ -20,7 +20,8 @@ data "aws_lambda_invocation" "worker_invoke_build" {
     source        = "io.sellalong.lambda-cd-worker"
     "detail-type" = "BUILD"
     detail = {
-      commands = var.build_commands
+      commands    = var.build_commands
+      environment = var.build_environment_variables
       s3 = {
         sources = {
           bucket    = local.package_sources.bucket