From 874c18caa1e4ff606b5280553a800f66d596794d Mon Sep 17 00:00:00 2001
From: Nicolas Froidure <nicolas.froidure@gmail.com>
Date: Sat, 25 Sep 2021 14:40:25 +0200
Subject: [PATCH] feat(lambda): add a layer for lambdas

---
 .gitignore                                  |  1 +
 package.json                                |  3 ++-
 packages/whook-example/README.md            |  6 ++++++
 packages/whook-example/bin/lambda_layer.sh  |  7 +++++++
 packages/whook-example/package.json         |  3 ++-
 packages/whook-example/terraform/lambdas.tf | 12 ++++++++++++
 6 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100755 packages/whook-example/bin/lambda_layer.sh

diff --git a/.gitignore b/.gitignore
index 108c1625..7ef20f06 100644
--- a/.gitignore
+++ b/.gitignore
@@ -137,3 +137,4 @@ lambdas
 *.plan
 *.tfstate.d
 *.credentials.json
+lambda_layer.zip
diff --git a/package.json b/package.json
index f24d0f68..8ecf93ee 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,8 @@
         ".terraform",
         "*.plan",
         "*.tfstate.d",
-        "*.credentials.json"
+        "*.credentials.json",
+        "lambda_layer.zip"
       ],
       "rootPackage": true
     }
diff --git a/packages/whook-example/README.md b/packages/whook-example/README.md
index 0b9bd00c..6a869e24 100644
--- a/packages/whook-example/README.md
+++ b/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
diff --git a/packages/whook-example/bin/lambda_layer.sh b/packages/whook-example/bin/lambda_layer.sh
new file mode 100755
index 00000000..36738745
--- /dev/null
+++ b/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;
diff --git a/packages/whook-example/package.json b/packages/whook-example/package.json
index 4e77c88f..74fedf18 100644
--- a/packages/whook-example/package.json
+++ b/packages/whook-example/package.json
@@ -39,7 +39,8 @@
         ".terraform",
         "*.plan",
         "*.tfstate.d",
-        "*.credentials.json"
+        "*.credentials.json",
+        "lambda_layer.zip"
       ],
       "bundleFiles": [
         "bin",
diff --git a/packages/whook-example/terraform/lambdas.tf b/packages/whook-example/terraform/lambdas.tf
index 2cb95ba4..61c26448 100644
--- a/packages/whook-example/terraform/lambdas.tf
+++ b/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),