Building and deploying Clojurescript aws lambda with shadow-cljs to fit in lambda@edge

Build and Deploy CLJS Lambda with minimal size.md

Some excerpts of how we build and deploy two lambdas. In this case these will end up as lambda@edge for a cloudfront distribution for handling viewer-requests and origin-requests.

The main point is how the origin-request lambda in the deploy-lambda section includes the node_modules directory into the lambda zip image. Lambda@edge can't have the image be bigger than 50MB. So we do

yarn install --production

To install only the production parts of the dependencies, Then use modclean to reduce the size of node_modules further.

Had problems doing the direct file upload for aws lambda update-function-code so used the s3 upload option for the origin-request lambda.

Makefile

ORIGIN_FUNCTION=socialiteOrigin
VIEWER_FUNCTION=socialiteViewer

build:
	yarn install --production
	npx modclean -r -n default:safe,default:caution
	npx shadow-cljs release :lambda-viewer
	npx shadow-cljs release :lambda-origin

deploy-lambda:
  # Viewer-request lambda
  cd dist/lambda-viewer && zip lambda-viewer.zip index.js && \
	aws lambda update-function-code --no-cli-pager --publish \
	--function-name $(VIEWER_FUNCTION) --zip-file fileb://lambda-viewer.zip
  # origin-request lambda
	cd dist/lambda-origin && \
	ln -f -s ../../node_modules . && \
	rm -f lambda-origin.zip && \
	pwd && \
	zip -q -r lambda-origin.zip index.js node_modules && \
	aws s3 cp lambda-origin.zip s3://some-s3-bucket && \
	aws lambda update-function-code --no-cli-pager --publish \
	--function-name $(ORIGIN_FUNCTION) \
	--s3-bucket some-s3-bucket --s3-key lambda-origin.zip

shadow-cljs.edn

{:deps   true
 :builds {:lambda-viewer {:target           :node-library
                          :output-to        "./dist/lambda-viewer/index.js"
                          :exports          {:handler visx.socialite.viewer/handler}
                          :compiler-options {:infer-externs :auto}}
          :lambda-origin {:target           :node-library
                          :output-to        "./dist/lambda-origin/index.js"
                          :exports          {:handler visx.socialite.origin/handler}
                          :compiler-options {:infer-externs :auto}}
          :node          {:target    :node-script
                          :output-to "./dist/node/index.js"
                          :main      visx.socialite.main/start
                          :devtools  {:after-load visx.socialite.main/reload}}
          :test          {:target    :node-test
                          :output-to "out/node-tests.js"
                          :ns-regexp "-test$"
                          :autorun   true}}}