add support for caching

src/cache-distributions/pip-cache.ts

@@ -0,0 +1,47 @@
+import * as glob from '@actions/glob';
+import * as core from '@actions/core';
+import * as exec from '@actions/exec';
+
+import * as path from 'path';
+import os from 'os';
+
+import CacheDistributor from './cache-distributor';
+
+class PipCache extends CacheDistributor {
+  constructor(patterns: string = '**/requirements.txt') {
+    super('pip', patterns);
+  }
+
+  protected async getCacheGlobalDirectories() {
+    const {stdout, stderr, exitCode} = await exec.getExecOutput(
+      'pip cache dir'
+    );
+    if (stderr) {
+      throw new Error(
+        `Could not get cache folder path for pip package manager`
+      );
+    }
+
+    let resolvedPath = stdout.trim();
+
+    if (resolvedPath.includes('~')) {
+      resolvedPath = path.join(os.homedir(), resolvedPath.slice(1));
+    }
+
+    core.info(`global cache directory path is ${resolvedPath}`);
+
+    return [resolvedPath];
+  }
+
+  protected async computeKeys() {
+    const hash = await glob.hashFiles(this.patterns);
+    const primaryKey = `${this.CACHE_KEY_PREFIX}-${process.env['RUNNER_OS']}-${this.toolName}-${hash}`;
+    const restoreKey = `${this.CACHE_KEY_PREFIX}-${process.env['RUNNER_OS']}-${this.toolName}-`;
+    return {
+      primaryKey,
+      restoreKey: [restoreKey]
+    };
+  }
+}
+
+export default PipCache;