fix: retry connections to gce metadata server

package.json

@@ -24,7 +24,8 @@
     "gtoken": "^2.1.0",
     "jws": "^3.1.4",
     "lodash.isstring": "^4.0.1",
-    "lru-cache": "^4.1.1"
+    "lru-cache": "^4.1.1",
+    "retry-axios": "^0.3.0"
   },
   "devDependencies": {
     "@justinbeckwith/typedoc": "^0.10.1",

src/auth/computeclient.ts

@@ -14,15 +14,18 @@
  * limitations under the License.
  */
 
-import {AxiosError, AxiosPromise, AxiosRequestConfig, AxiosResponse} from 'axios';
+import axios, {AxiosError, AxiosPromise, AxiosRequestConfig, AxiosResponse} from 'axios';
 import {BASE_PATH, HEADER_NAME, HOST_ADDRESS} from 'gcp-metadata';
-
-import {RequestError} from './../transporters';
+import * as rax from 'retry-axios';
 import {CredentialRequest, Credentials} from './credentials';
 import {GetTokenResponse, OAuth2Client, RefreshOptions} from './oauth2client';
 
 export interface ComputeOptions extends RefreshOptions {}
 
+// Create a scoped axios instance that will retry 3 times by default
+const ax = axios.create();
+rax.attach(ax);
+
 export class Compute extends OAuth2Client {
   /**
    * Google Compute Engine metadata server token endpoint.
@@ -68,8 +71,11 @@ export class Compute extends OAuth2Client {
     try {
       // TODO: In 2.0, we should remove the ability to configure the tokenUrl,
       // and switch this over to use the gcp-metadata package instead.
-      res = await this.transporter.request<CredentialRequest>(
-          {url, headers: {'Metadata-Flavor': 'Google'}});
+      res = await ax.request<CredentialRequest>({
+        url,
+        headers: {'Metadata-Flavor': 'Google'},
+        raxConfig: {noResponseRetries: 3, retry: 3, instance: ax}
+      } as rax.RaxConfig);
     } catch (e) {
       e.message = 'Could not refresh access token.';
       throw e;
@@ -109,7 +115,7 @@ export class Compute extends OAuth2Client {
             e.message = helpfulMessage;
           } else {
             e = new Error(helpfulMessage);
-            (e as RequestError).code = res.status.toString();
+            (e as NodeJS.ErrnoException).code = res.status.toString();
           }
         }
       }

test/test.compute.ts

@@ -15,12 +15,10 @@
  */
 
 import * as assert from 'assert';
-import {AxiosRequestConfig} from 'axios';
 import {BASE_PATH, HOST_ADDRESS} from 'gcp-metadata';
 import * as nock from 'nock';
 
 import {Credentials} from '../src/auth/credentials';
-import {GoogleAuth} from '../src/auth/googleauth';
 import {Compute} from '../src/index';
 
 nock.disableNetConnect();
@@ -120,6 +118,44 @@ describe('Compute auth client', () => {
     });
   });
 
+  it('should retry calls to the metadata service if there are network errors',
+     (done) => {
+       const scopes = [
+         nock(HOST_ADDRESS).get(tokenPath).times(2).replyWithError({
+           code: 'ENOTFOUND'
+         }),
+         nock(HOST_ADDRESS).get(tokenPath).reply(200, {
+           access_token: 'abc123',
+           expires_in: 10000
+         })
+       ];
+       compute.credentials.access_token = 'initial-access-token';
+       compute.credentials.expiry_date = (new Date()).getTime() - 10000;
+       compute.request({url: 'http://foo'}, e => {
+         assert.equal(compute.credentials.access_token, 'abc123');
+         scopes.forEach(s => s.done());
+         done();
+       });
+     });
+
+  it('should retry calls to the metadata service if it returns non-200 errors',
+     (done) => {
+       const scopes = [
+         nock(HOST_ADDRESS).get(tokenPath).times(2).reply(500),
+         nock(HOST_ADDRESS).get(tokenPath).reply(200, {
+           access_token: 'abc123',
+           expires_in: 10000
+         })
+       ];
+       compute.credentials.access_token = 'initial-access-token';
+       compute.credentials.expiry_date = (new Date()).getTime() - 10000;
+       compute.request({url: 'http://foo'}, e => {
+         assert.equal(compute.credentials.access_token, 'abc123');
+         scopes.forEach(s => s.done());
+         done();
+       });
+     });
+
   describe('.createScopedRequired', () => {
     it('should return false', () => {
       const c = new Compute();