Update to labeler v2 (#4)

* labeler v2

* update docs

src/main.ts

@@ -0,0 +1,146 @@
+import * as core from '@actions/core';
+import * as github from '@actions/github';
+import * as yaml from 'js-yaml';
+import {Minimatch} from 'minimatch';
+
+async function run() {
+  try {
+    const token = core.getInput('repo-token', {required: true});
+    const configPath = core.getInput('configuration-path', {required: true});
+
+    const prNumber = getPrNumber();
+    if (!prNumber) {
+      console.log('Could not get pull request number from context, exiting');
+      return;
+    }
+
+    const client = new github.GitHub(token);
+
+    core.debug(`fetching changed files for pr #${prNumber}`);
+    const changedFiles: string[] = await getChangedFiles(client, prNumber);
+    const labelGlobs: Map<string, string[]> = await getLabelGlobs(
+      client,
+      configPath
+    );
+
+    const labels: string[] = [];
+    for (const [label, globs] of labelGlobs.entries()) {
+      core.debug(`processing ${label}`);
+      if (checkGlobs(changedFiles, globs)) {
+        labels.push(label);
+      }
+    }
+
+    if (labels.length > 0) {
+      await addLabels(client, prNumber, labels);
+    }
+  } catch (error) {
+    core.error(error);
+    core.setFailed(error.message);
+  }
+}
+
+function getPrNumber(): number | undefined {
+  const pullRequest = github.context.payload.pull_request;
+  if (!pullRequest) {
+    return undefined;
+  }
+
+  return pullRequest.number;
+}
+
+async function getChangedFiles(
+  client: github.GitHub,
+  prNumber: number
+): Promise<string[]> {
+  const listFilesResponse = await client.pulls.listFiles({
+    owner: github.context.repo.owner,
+    repo: github.context.repo.repo,
+    pull_number: prNumber
+  });
+
+  const changedFiles = listFilesResponse.data.map(f => f.filename);
+
+  core.debug('found changed files:');
+  for (const file of changedFiles) {
+    core.debug('  ' + file);
+  }
+
+  return changedFiles;
+}
+
+async function getLabelGlobs(
+  client: github.GitHub,
+  configurationPath: string
+): Promise<Map<string, string[]>> {
+  const configurationContent: string = await fetchContent(
+    client,
+    configurationPath
+  );
+
+  // loads (hopefully) a `{[label:string]: string | string[]}`, but is `any`:
+  const configObject: any = yaml.safeLoad(configurationContent);
+
+  // transform `any` => `Map<string,string[]>` or throw if yaml is malformed:
+  return getLabelGlobMapFromObject(configObject);
+}
+
+async function fetchContent(
+  client: github.GitHub,
+  repoPath: string
+): Promise<string> {
+  const response = await client.repos.getContents({
+    owner: github.context.repo.owner,
+    repo: github.context.repo.repo,
+    path: repoPath
+  });
+
+  return Buffer.from(response.data.content, 'base64').toString();
+}
+
+function getLabelGlobMapFromObject(configObject: any): Map<string, string[]> {
+  const labelGlobs: Map<string, string[]> = new Map();
+  for (const label in configObject) {
+    if (typeof configObject[label] === 'string') {
+      labelGlobs.set(label, [configObject[label]]);
+    } else if (configObject[label] instanceof Array) {
+      labelGlobs.set(label, configObject[label]);
+    } else {
+      throw Error(
+        `found unexpected type for label ${label} (should be string or array of globs)`
+      );
+    }
+  }
+
+  return labelGlobs;
+}
+
+function checkGlobs(changedFiles: string[], globs: string[]): boolean {
+  for (const glob of globs) {
+    core.debug(` checking pattern ${glob}`);
+    const matcher = new Minimatch(glob);
+    for (const changedFile of changedFiles) {
+      core.debug(` - ${changedFile}`);
+      if (matcher.match(changedFile)) {
+        core.debug(` ${changedFile} matches`);
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+async function addLabels(
+  client: github.GitHub,
+  prNumber: number,
+  labels: string[]
+) {
+  await client.issues.addLabels({
+    owner: github.context.repo.owner,
+    repo: github.context.repo.repo,
+    issue_number: prNumber,
+    labels: labels
+  });
+}
+
+run();