GitHub Actions Expressions

Written like:

env:
  SOME_INT: ${{ 123 }}
  SOME_FLOAT: ${{ 123.123 }}
  SOME_HEX: ${{ 0xff }}

  # Strings contained in expressions are single-quoted
  SOME_STRING: ${{ 'It''s-a me!' }}

Truthiness matches exactly with JavaScript.

See the docs on expressions

Conditional expressions

jobs.<job-id>.if takes in an expression which evaluates to a boolean.

You can omit the usual $ for if blocks, as GitHub Actions will always parse the value as an expression by default.

However, you need to keep it if using !, since that is a reserved token for YAML.

See the documentation on conditions controlling job execution

Contexts

A context is an object containing key/values who are automatically populated with information about the jobs being run.

For example, the github context contains information about:

• the actor (user) who started the action (github.actor)
• the repository being acted on (github.repository)
• the fully formed git ref name (github.ref)
• the short ref name (github.ref_name)

See the documentation on contexts