Configure webhook

When using Pact in a CI/CD pipeline, there are two reasons for a pact verification task to take place:

  • When the provider changes (to make sure it does not break any existing consumer expectations)

  • When a pact changes (to see if the provider is compatible with the new expectations)

To ensure that the verification step is run whenever a pact changes, we need to configure a API Hub for Contract Testing webhook to trigger a provider verification build in Github Actions.

You can see the configuration for this build in .github/workflows/contract_requiring_verification_published.yml in the provider project.

Rather than verifying the pacts with the configured consumer version selectors, it triggers once for each of the following provider versions that are missing a verification result for the newly published pact:

  • the latest version from the provider's main branch

  • any version currently deployed to an environment

This is achieved by passing the URL of the changed pact to the build via a parameter in the body of the webhook request, as well as the provider version number and the provider branch of the head, test and production versions.

See here for in-depth details about the "contract requiring verification published" event.

The API Hub for Contract Testing webhook will need a Github access token to be able to trigger the build in Github. We don't want the Github token to be stored in clear text in the webhook, so we will create a secret in API Hub for Contract Testing to contain token.

  1. Create a Github token.

    1. In Github:

      1. Open the Personal access tokens page

        1. Click on your profile picture in the top right of the window.

        2. Select Settings -> Select Developer settings from the bottom of the menu on the left -> Select Personal access tokens from the menu on the left.

      2. Click Generate new token

      3. Set Note to Token for triggering example-provider pact verification build

      4. Select public_repo scope.

      5. Select an Expiration period for your token

      6. Click Generate token

      7. Copy the value of the token and put it in an open file (or better yet, store it in your password manager!)

  2. Create a API Hub for Contract Testing secret for the Github token.

    1. In your API Hub for Contract Testing account:

      1. Go to the Secrets page

        1. Click on the Settings icon in the top left (it looks like a cog wheel) -> Select the Secrets tab from the menu on the left.

      2. Click "ADD SECRET"

      3. Select "None" in the team drop down box

      4. Enter the name githubToken and paste the value that you copied in the previous step.

      5. Click "CREATE"

  3. Create the "contract requiring verification published" webhook.

    1. In your API Hub for Contract Testing account:

      1. Select the Webhooks tab from the settings page.

      2. Click "ADD WEBHOOK".

      3. Set:

        • Team: None

        • Description: Contract requiring verification published webhook for pactflow-example-provider

        • Consumer: leave as "ALL"

        • Provider: select pactflow-example-provider

        • Events: select Contract published that requires verification

        • URL:

          https://api.github.com/repos/<YOUR GITHUB ACCOUNT HERE>/example-provider/dispatches

        • Headers:

          Content-Type: application/json
Accept: application/vnd.github.everest-preview+json
Authorization: Bearer ${user.githubToken}

        • Body:

          {
    "event_type": "contract_requiring_verification_published",
    "client_payload": {
        "pact_url": "${pactbroker.pactUrl}",
        "sha": "${pactbroker.providerVersionNumber}",
        "branch": "${pactbroker.providerVersionBranch}",
        "message": "Verify changed pact for ${pactbroker.consumerName} version ${pactbroker.consumerVersionNumber} branch ${pactbroker.consumerVersionBranch} by ${pactbroker.providerVersionNumber} (${pactbroker.providerVersionDescriptions})"
        }
}

      4. Click the "TEST" button and ensure that it runs successfully.

        👉 The Github API returns a 404 instead of an authorization error if the token is not correctly set. If you see a 404, it may be that the URL is incorrect, or it may be that the access token is not configured correctly.

      5. Click the "CREATE" button.

  4. Verify that the contract_requiring_verification_published verification build for the provider is running correctly

    1. In Github

      1. Open the Github Actions page for the "contract_requiring_verification_published" workflow

        1. Click Actions -> Under Workflows, select contract_requiring_verification_published

      2. Select the latest execution

        1. This was triggered by pressing the TEST button in our webhook. In our CI/CD workflow, this will be triggered when a real Contract published that requires verification event takes place

👉 Each of the above steps can be automated in API Hub for Contract Testing via the API Hub for Contract Testing API - you can see the targets for the commands in the provider's Makefile.

Expected state by the end of this step

  • Both consumer and provider builds passing ✅

  • A webhook that has been tested and shown to trigger a pact verification build of the provider.

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