Speed up the AWS Elastic Beanstalk of your Rails deployment with bundle/assets caching

cache.yml

# .ebextensions/cache.config
files:
  "/opt/elasticbeanstalk/hooks/appdeploy/pre/02a_set_cache.sh":
    mode: "000755"
    owner: root
    group: root
    content: |
      #!/bin/bash
      set -xe

      EB_APP_STAGING_DIR=$(/opt/elasticbeanstalk/bin/get-config container -k app_staging_dir)

      BUCKET="elasticbeanstalk-PUT_YOUR_REGION-PUT_YOUR_ACCOUNT_ID"
      mkdir -p /tmp/cache
      if aws s3 ls s3://${BUCKET}/cache/gem.tar.gz ; then
        aws s3 cp --quiet s3://${BUCKET}/cache/gem.tar.gz /tmp/cache/gem.tar.gz
      fi
      if aws s3 ls s3://${BUCKET}/cache/node_modules.tar.gz ; then
        aws s3 cp --quiet s3://${BUCKET}/cache/node_modules.tar.gz /tmp/cache/node_modules.tar.gz
      fi
      if aws s3 ls s3://${BUCKET}/cache/assets.tar.gz ; then
        aws s3 cp --quiet s3://${BUCKET}/cache/assets.tar.gz /tmp/cache/assets.tar.gz
      fi

      [ -f /tmp/cache/gem.tar.gz ]          && tar -xf /tmp/cache/gem.tar.gz          -C $EB_APP_STAGING_DIR && chown webapp:webapp -R "$EB_APP_STAGING_DIR/vendor/bundle"
      [ -f /tmp/cache/node_modules.tar.gz ] && tar -xf /tmp/cache/node_modules.tar.gz -C $EB_APP_STAGING_DIR && chown webapp:webapp -R "$EB_APP_STAGING_DIR/node_modules"
      [ -f /tmp/cache/assets.tar.gz ]       && tar -xf /tmp/cache/assets.tar.gz       -C $EB_APP_STAGING_DIR && chown webapp:webapp -R "$EB_APP_STAGING_DIR/tmp"
      exit 0

  "/opt/elasticbeanstalk/hooks/appdeploy/pre/11a_build_cache.sh":
    mode: "000755"
    owner: root
    group: root
    content: |
      #!/bin/bash
      set -xe

      EB_APP_STAGING_DIR=$(/opt/elasticbeanstalk/bin/get-config container -k app_staging_dir)

      cd $EB_APP_STAGING_DIR
      mkdir -p /tmp/cache
      tar -zcf /tmp/cache/gem.tar.gz          vendor/bundle
      tar -zcf /tmp/cache/node_modules.tar.gz node_modules
      tar -zcf /tmp/cache/assets.tar.gz       tmp/cache/assets

      BUCKET="elasticbeanstalk-PUT_YOUR_REGION-PUT_YOUR_ACCOUNT_ID"
      aws s3 cp /tmp/cache/gem.tar.gz          s3://${BUCKET}/cache/gem.tar.gz
      aws s3 cp /tmp/cache/node_modules.tar.gz s3://${BUCKET}/cache/node_modules.tar.gz
      aws s3 cp /tmp/cache/assets.tar.gz       s3://${BUCKET}/cache/assets.tar.gz

I updated my gist with commands to push the cache to the Elastic Beanstalk S3 bucket. You'll find it in your console

One consideration is that somehow the current rails stack will use root user and vendor/bundle is not available and will fail the tar command.

Is there a fix for that?

Thanks for posting this. If I want to use this with multiple apps all running in the same region, does it stand to reason that modifying the BUCKET would be the right way to support that?

e.g.

BUCKET="elasticbeanstalk-PUT_YOUR_REGION-PUT_YOUR_ACCOUNT_ID-APP_NAME"

Also, I assume I can reference my app's env vars during 02a_set_cache.sh?

Thanks again!