A new version of the Elastic Beanstalk container removed the very useful $EB_CONFIG_* environment variables. This puts them back, as $EB_CONTAINER_*.

00-eb_container_envvars.config

# The Ruby script at /opt/elasticbeanstalk/support/get_envvars.rb is responsible for compiling a list of
#  environment variables for use throughout the system. This patches that file to add the EB container variables.
#  Most of the added $EB_CONTAINER_* directly match the old $EB_CONFIG_* variables that Elastic Beanstalk did away with
#  in a recent container version update; however, $EB_CONFIG_APP_CURRENT is now $EB_CONTAINER_APP_DEPLOY.
# Note: Since we're using `git apply` as a "better GNU patch" we need to pass `--unsafe-paths` in Git >=2.3.0
# See https://gist.github.com/airdrummingfool/29e73d6dfa68ec5da92e for updates and changelog

files:
  "/tmp/add_container_envvars.patch" :
    mode: "000755"
    owner: root
    group: users
    content: |
      --- ./get_envvars.rb  2015-01-28 01:52:31.000000000 +0000
      +++ ./get_envvars.rb  2015-03-11 23:05:09.224547106 +0000
      @@ -5,8 +5,10 @@
       def get_env_vars
           env_vars = JSON.parse(`/opt/elasticbeanstalk/bin/get-config environment`)
           php_env_vars = JSON.parse(`/opt/elasticbeanstalk/bin/get-config optionsettings -n "aws:elasticbeanstalk:container:php:phpini"`)
      +    container_vars = JSON.parse(`/opt/elasticbeanstalk/bin/get-config container`)
           
           php_env_vars.each { |key, value| env_vars['PHP_' + key.upcase] = value }
      +    container_vars.each { |key, value| next if !value.is_a?(String); env_vars['EB_CONTAINER_' + key.chomp("_dir").upcase] = value }
           
           env_vars['PHP_DATE_TIMEZONE'] = 'UTC';
       

commands:
  01-patch_get_envvars.rb:
    command: grep --silent "container_vars" /opt/elasticbeanstalk/support/get_envvars.rb || git apply /tmp/add_container_envvars.patch --directory=/opt/elasticbeanstalk/support --ignore-whitespace --unsafe-paths

The 5th revision of this config file limits container variables to strings only. Elastic Beanstalk's PHP image v2.2.0+ includes some arrays in the output of /opt/elasticbeanstalk/bin/get-config container, and there is code that relies on get_envvars.rb that assumes that all env_vars are strings. If they aren't all strings, an error like the following may occur:

/opt/elasticbeanstalk/support/php_apache_env:7:in `add_slashes': undefined method `gsub' for ["/var/log/httpd/error_log", "/var/log/httpd/access_log"]:Array (NoMethodError)

Because this file is implemented as a patch (mostly so that if get_envvars.rb changes, this breaks in a noticeable way), this revision will not fix already patched instances. This means that in order to upgrade an existing instance to v2.2.0+, you must manually apply this patch, or revert the previous patch job and then re-deploy. I recommend a simpler solution: set your Configuration Updates "Rolling update type" to Immutable, which spins up new instances to replace the old ones (this is safer in other ways too, it just takes longer). As long as you do this, you simply have to make sure this revision of the config file is in your currently running application version (i.e. the latest deployment in the environment you're updating) before you start the update to 2.2.0+.

The 6th revision simply adds a link back to this gist.