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The tkn pac cel command provides an interactive CEL expression evaluator that helps you test and debug CEL expressions used in PipelineRun annotations before deploying them.

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Usage

tkn pac cel [flags]

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Description

The CEL evaluator allows you to interactively test CEL expressions against real or simulated webhook payloads. It automatically detects the Git provider from webhook headers and payload structure, making it easy to verify your event matching logic. This is particularly useful when creating complex on-cel-expression annotations for conditional pipeline execution.

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Flags

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--body
string
Path to a JSON file containing the webhook payload body
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--headers
string
Path to a JSON file containing the webhook headers
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--provider
string
Specify the Git provider explicitly (github, gitlab, bitbucket-cloud, bitbucket-datacenter, forgejo)If not specified, the provider is auto-detected from the payload
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--github-token
string
GitHub token for API operations when evaluating expressions that access GitHub API

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Interactive Mode

When you run tkn pac cel without files, it starts in interactive mode where you can:
  1. Type CEL expressions directly
  2. View available variables and their values
  3. Test expressions against the loaded webhook payload
  4. Get immediate feedback on expression evaluation
Type help in interactive mode to see available commands and variables.

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Examples

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Evaluate expression with webhook payload

tkn pac cel --body payload.json --headers headers.json

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Specify provider explicitly

tkn pac cel --provider github --body github-payload.json

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Test file path matching

# In interactive mode, test expressions like:
# files.all.exists(x, x.matches("src/.*\\.go"))
tkn pac cel --body pull-request-payload.json

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Common Use Cases

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Test path change detection

Create a payload.json with your pull request webhook data and test path matching: 
files.all.exists(x, x.matches("docs/.*"))

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Verify event conditions

Test complex conditions before adding them to your PipelineRun: 
event == "pull_request" && source_branch.startsWith("feature/")

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Debug custom parameters

Test parameter filtering expressions: 
target_branch == "main" || target_branch == "production"

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Available Variables

The CEL evaluator provides access to all standard PAC variables:
  • event - Event type (pull_request, push, incoming)
  • source_branch - Source branch name
  • target_branch - Target branch name
  • files - File changes (for pull requests)
  • body - Full webhook payload
  • headers - Webhook headers
  • Custom variables specific to each provider
Run the command in interactive mode and type help to see the complete list of variables for your provider.

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Troubleshooting

Verify your JSON files contain valid webhook payloads. You can capture real payloads using webhook inspection tools or from your Git provider’s webhook delivery logs.
Ensure the payload contains the necessary fields. Some variables are only available for specific event types (e.g., files is only available for pull requests).
Use the --provider flag to explicitly specify your Git provider if auto-detection fails.

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See Also

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