feat(lambda): add a layer for lambdas

.gitignore

@@ -137,3 +137,4 @@ lambdas
 *.plan
 *.tfstate.d
 *.credentials.json
+lambda_layer.zip

package.json

@@ -20,7 +20,8 @@
         ".terraform",
         "*.plan",
         "*.tfstate.d",
-        "*.credentials.json"
+        "*.credentials.json",
+        "lambda_layer.zip"
       ],
       "rootPackage": true
     }

packages/whook-example/README.md

@@ -108,6 +108,12 @@ Build the lambdas and the commands Terraform depends on:
 NODE_ENV=staging npm run build
 ```
 
+Build the lambdas layer:
+
+```sh
+NODE_ENV=staging bin/lambda_layer.sh
+```
+
 Plan the deployment:
 
 ```sh

packages/whook-example/bin/lambda_layer.sh

@@ -0,0 +1,7 @@
+mkdir -p layer/nodejs;
+cp package.json layer/nodejs/package.json;
+cp package-lock.json layer/nodejs/package-lock.json;
+docker run --entrypoint "" -v "$PWD/layer/nodejs":/var/task "public.ecr.aws/lambda/nodejs:14" /bin/sh -c "yum install -y gcc gcc-c++ make; npm i --production; sudo chown -R $USER /var/task; exit";
+env --chdir "$PWD/layer" zip -r ../lambda_layer.zip .;
+docker run --entrypoint "" -v "$PWD/layer/nodejs":/var/task "public.ecr.aws/lambda/nodejs:14" /bin/sh -c "rm -rf node_modules; exit";
+rm -rf layer/nodejs;

packages/whook-example/package.json

@@ -39,7 +39,8 @@
         ".terraform",
         "*.plan",
         "*.tfstate.d",
-        "*.credentials.json"
+        "*.credentials.json",
+        "lambda_layer.zip"
       ],
       "bundleFiles": [
         "bin",

packages/whook-example/terraform/lambdas.tf

@@ -71,6 +71,17 @@ data "external" "envvars" {
   working_dir = ".."
 }
 
+resource "aws_lambda_layer_version" "lambda_layer" {
+  filename            = "../lambda_layer.zip"
+  layer_name          = "api-lambda-layer"
+  description         = "A layer with all lambdas node modules"
+  source_code_hash    = filebase64sha256("../lambda_layer.zip")
+  # You may replace the above by the following to avoid pushing
+  # a new layer when the package lock did not change
+  # source_code_hash    = filebase64sha256("../package-lock.json")
+  compatible_runtimes = ["nodejs14.x"]
+}
+
 data "archive_file" "lambdas" {
   for_each    = data.external.lambdas.result
   type        = "zip"
@@ -88,6 +99,7 @@ resource "aws_lambda_function" "lambda_function" {
   source_code_hash = data.archive_file.lambdas[each.key].output_base64sha256
   memory_size      = split("|", each.value)[3]
   timeout          = split("|", each.value)[2]
+  layers           = [aws_lambda_layer_version.lambda_layer.arn]
   environment {
     variables = zipmap(
       keys(data.external.envvars.result),