Add test and better logs

This commit adds a test to retrieving auth configurations, use either
the auth block in the config or specified via the agent config and adds
a log if lookup fails.

client/driver/docker.go

@@ -986,15 +986,18 @@ func (d *DockerDriver) pullImage(driverConfig *DockerDriverConfig, client *docke
 			Email:         driverConfig.Auth[0].Email,
 			ServerAddress: driverConfig.Auth[0].ServerAddress,
 		}
-	}
-	if authConfigFile := d.config.Read("docker.auth.config"); authConfigFile != "" {
+	} else if authConfigFile := d.config.Read("docker.auth.config"); authConfigFile != "" {
 		authOptionsPtr, err := authOptionFrom(authConfigFile, repo)
 		if err != nil {
 			d.logger.Printf("[INFO] driver.docker: failed to find docker auth for repo %q: %v", repo, err)
 			return fmt.Errorf("Failed to find docker auth for repo %q: %v", repo, err)
 		}
 
 		authOptions = *authOptionsPtr
+		if authOptions.Email == "" && authOptions.Password == "" &&
+			authOptions.ServerAddress == "" && authOptions.Username == "" {
+			d.logger.Printf("[DEBUG] driver.docker: did not find docker auth for repo %q", repo)
+		}
 	}
 
 	d.emitEvent("Downloading image %s:%s", repo, tag)
@@ -1391,7 +1394,7 @@ func calculatePercent(newSample, oldSample, newTotal, oldTotal uint64, cores int
 	return (float64(numerator) / float64(denom)) * float64(cores) * 100.0
 }
 
-// authOptionsFrom takes the Docker auth config file and the repo being pulled
+// authOptionFrom takes the Docker auth config file and the repo being pulled
 // and returns an AuthConfiguration or an error if the file/repo could not be
 // parsed or looked up.
 func authOptionFrom(file, repo string) (*docker.AuthConfiguration, error) {

client/driver/docker_test.go

@@ -1330,3 +1330,54 @@ func copyImage(t *testing.T, taskDir *allocdir.TaskDir, image string) {
 	dst := filepath.Join(taskDir.LocalDir, image)
 	copyFile(filepath.Join("./test-resources/docker", image), dst, t)
 }
+
+func TestDockerDriver_AuthConfiguration(t *testing.T) {
+	path := "./test-resources/docker/auth.json"
+	cases := []struct {
+		Repo       string
+		AuthConfig *docker.AuthConfiguration
+	}{
+		{
+			Repo:       "lolwhat.com/what:1337",
+			AuthConfig: &docker.AuthConfiguration{},
+		},
+		{
+			Repo: "redis:3.2",
+			AuthConfig: &docker.AuthConfiguration{
+				Username:      "test",
+				Password:      "1234",
+				Email:         "",
+				ServerAddress: "https://index.docker.io/v1/",
+			},
+		},
+		{
+			Repo: "quay.io/redis:3.2",
+			AuthConfig: &docker.AuthConfiguration{
+				Username:      "test",
+				Password:      "5678",
+				Email:         "",
+				ServerAddress: "quay.io",
+			},
+		},
+		{
+			Repo: "other.io/redis:3.2",
+			AuthConfig: &docker.AuthConfiguration{
+				Username:      "test",
+				Password:      "abcd",
+				Email:         "",
+				ServerAddress: "https://other.io/v1/",
+			},
+		},
+	}
+
+	for i, c := range cases {
+		act, err := authOptionFrom(path, c.Repo)
+		if err != nil {
+			t.Fatalf("Test %d failed: %v", i+1, err)
+		}
+
+		if !reflect.DeepEqual(act, c.AuthConfig) {
+			t.Fatalf("Test %d failed: Unexpected auth config: got %+v; want %+v", i+1, act, c.AuthConfig)
+		}
+	}
+}

client/driver/test-resources/docker/auth.json

@@ -0,0 +1,13 @@
+{
+    "auths": {
+        "https://index.docker.io/v1/": {
+            "auth": "dGVzdDoxMjM0"
+        },
+        "quay.io": {
+            "auth": "dGVzdDo1Njc4"
+        },
+        "https://other.io/v1/": {
+            "auth": "dGVzdDphYmNk"
+        }
+    }
+}