feat: add label filter to reduce scope of action

README.md

@@ -115,5 +115,20 @@ Add the PR creator as assignee to the pull request.
 addAssignees: author
 ```
 
+### Filter by label
+The action will only run if the PR meets the specified filters
+
+```yaml
+filterLabels:
+  # Run
+  include:
+    - my_label
+    - another_label
+  # Not run
+  exclude:
+    - wip
+
+```
+
 ## :memo: Licence
 MIT

__tests__/handler.test.ts

@@ -20,6 +20,7 @@ describe('handlePullRequest', () => {
         number: '1',
         pull_request: {
           number: 1,
+          labels: [],
           title: 'test',
           user: {
             login: 'pr-creator',
@@ -822,4 +823,73 @@ describe('handlePullRequest', () => {
       /group3-reviewer/
     )
   })
+
+  test('skips pull requests that do not have any of the filterLabels.include labels', async () => {
+    const spy = jest.spyOn(core, 'info')
+
+    const client = new github.GitHub('token')
+    const config = {
+      filterLabels: { include: ['test_label'] },
+    } as any
+
+    context.payload.pull_request.labels = [{ name: 'some_label' }]
+
+    await handler.handlePullRequest(client, context, config)
+
+    expect(spy.mock.calls[0][0]).toEqual(
+      'Skips the process to add reviewers/assignees since PR is not tagged with any of the filterLabels.include'
+    )
+  })
+
+  test('skips pull requests that have any of the filterLabels.exclude labels', async () => {
+    const spy = jest.spyOn(core, 'info')
+
+    const client = new github.GitHub('token')
+    const config = {
+      filterLabels: { include: ['test_label'], exclude: ['wip'] },
+    } as any
+
+    context.payload.pull_request.labels = [
+      { name: 'test_label' },
+      { name: 'wip' },
+    ]
+
+    await handler.handlePullRequest(client, context, config)
+
+    expect(spy.mock.calls[0][0]).toEqual(
+      'Skips the process to add reviewers/assignees since PR is tagged with any of the filterLabels.exclude'
+    )
+  })
+
+  test('adds reviewers to the pull request when it has any of the configured labels', async () => {
+    const config = {
+      addAssignees: false,
+      addReviewers: true,
+      filterLabels: { include: ['some_label', 'another_label'] },
+      numberOfReviewers: 0,
+      reviewers: ['reviewer1', 'reviewer2', 'reviewer3', 'pr-creator'],
+    } as any
+
+    const client = new github.GitHub('token')
+
+    context.payload.pull_request.labels = [{ name: 'some_label' }]
+
+    client.pulls = {
+      createReviewRequest: jest.fn().mockImplementation(async () => {}),
+    } as any
+
+    const addAssigneesSpy = jest.spyOn(client.issues, 'addAssignees')
+    const createReviewRequestSpy = jest.spyOn(
+      client.pulls,
+      'createReviewRequest'
+    )
+
+    await handler.handlePullRequest(client, context, config)
+
+    expect(addAssigneesSpy).not.toBeCalled()
+    expect(createReviewRequestSpy.mock.calls[0][0].reviewers).toHaveLength(3)
+    expect(createReviewRequestSpy.mock.calls[0][0].reviewers[0]).toMatch(
+      /reviewer/
+    )
+  })
 })

src/handler.ts

@@ -9,6 +9,10 @@ export interface Config {
   addAssignees: boolean | string
   reviewers: string[]
   assignees: string[]
+  filterLabels?: {
+    include?: string[]
+    exclude?: string[]
+  }
   numberOfAssignees: number
   numberOfReviewers: number
   skipKeywords: string[]
@@ -36,6 +40,7 @@ export async function handlePullRequest(
     assigneeGroups,
     addReviewers,
     addAssignees,
+    filterLabels,
   } = config
 
   if (skipKeywords && utils.includesSkipKeywords(title, skipKeywords)) {
@@ -66,6 +71,28 @@ export async function handlePullRequest(
   const owner = user.login
   const pr = new PullRequest(client, context)
 
+  if (filterLabels !== undefined) {
+    if (filterLabels.include !== undefined && filterLabels.include.length > 0) {
+      const hasLabels = pr.hasAnyLabel(filterLabels.include)
+      if (!hasLabels) {
+        core.info(
+          'Skips the process to add reviewers/assignees since PR is not tagged with any of the filterLabels.include'
+        )
+        return
+      }
+    }
+
+    if (filterLabels.exclude !== undefined && filterLabels.exclude.length > 0) {
+      const hasLabels = pr.hasAnyLabel(filterLabels.exclude)
+      if (hasLabels) {
+        core.info(
+          'Skips the process to add reviewers/assignees since PR is tagged with any of the filterLabels.exclude'
+        )
+        return
+      }
+    }
+  }
+
   if (addReviewers) {
     try {
       const reviewers = utils.chooseReviewers(owner, config)

src/pull_request.ts

@@ -32,4 +32,12 @@ export class PullRequest {
     })
     core.debug(JSON.stringify(result))
   }
+
+  hasAnyLabel(labels: string[]): boolean {
+    if (!this.context.payload.pull_request) {
+      return false
+    }
+    const { labels: pullRequestLabels = [] } = this.context.payload.pull_request
+    return pullRequestLabels.some(label => labels.includes(label.name))
+  }
 }