Functions

All CEL standard functions and macros are available. Slipway adds the following.

Function	Description
hashFiles(glob...)	SHA-256 over the contents of all files matching the globs, for cache keys
contains(x, y)	String contains substring, or list contains element
startsWith(s, p) / endsWith(s, p)	Prefix and suffix tests (also available as methods)
format("{0}-{1}", a, b)	Positional string formatting
join(list, sep)	Join a list of strings
toJSON(v) / fromJSON(s)	Serialise to and parse JSON
glob(pattern, path)	Whether path matches pattern (** supported)
semver.gt(a, b), semver.lt(a, b)	Semver comparison
semver.satisfies(v, range)	Whether version v satisfies a range such as ">=1.2 <2"
success()	Every needed job succeeded (the default job if)
failure()	At least one needed job failed
always()	True regardless of results
cancelled()	The run was cancelled
fileExists(path)	Whether a path exists in the workspace. Job scope only
now()	Current timestamp
env(name)	Read an environment variable at the current scope

Examples

# Cache key from lockfiles
cache:
  - key: npm-${{ hashFiles("package-lock.json", "**/package-lock.json") }}
    paths: [~/.npm]

# Stable image tag
env:
  TAG: ${{ format("{0}-{1}", git.branch, git.short_sha) }}

# JSON from a step output
- run: echo "matrix=$(jq -c . services.json)" >> "$SLIPWAY_OUTPUT"
  id: plan
# ...in another job:
matrix:
  service: ${{ fromJSON(needs.plan.outputs.matrix) }}

# Release gating by version
if: semver.satisfies(release.version, ">=2.0.0 <3.0.0")

# Debug on failure
- run: ./dump-logs.sh
  if: failure()

# Skip a step when a file is absent
if: fileExists("Dockerfile")

Status functions

success(), failure(), always() and cancelled() always refer to the needed jobs when used at job level, and to the previous steps in the job when used at step level. A job if that does not call a status function behaves as if it were wrapped in success() &&. To run after a failure, say so:

- name: notify
  needs: [deploy]
  if: failure()

Errors

Expressions that fail to evaluate (for example indexing a missing key) fail the job with the expression and the offending value in the log. Use has(x.y) to test for a field’s presence first.