docker: configFile method

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

src/docker/docker.ts

@@ -14,17 +14,29 @@
  * limitations under the License.
  */
 
+import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as core from '@actions/core';
 import * as io from '@actions/io';
+
 import {Exec} from '../exec';
 
+import {ConfigFile} from '../types/docker';
+
 export class Docker {
   static get configDir(): string {
     return process.env.DOCKER_CONFIG || path.join(os.homedir(), '.docker');
   }
 
+  public static configFile(): ConfigFile | undefined {
+    const f = path.join(Docker.configDir, 'config.json');
+    if (!fs.existsSync(f)) {
+      return undefined;
+    }
+    return <ConfigFile>JSON.parse(fs.readFileSync(f, {encoding: 'utf-8'}));
+  }
+
   public static async isAvailable(): Promise<boolean> {
     return await io
       .which('docker', true)