From bdb0a09d79334bc3d4f90ce7ae35d02de634dadf Mon Sep 17 00:00:00 2001
From: David Gageot <david@gageot.net>
Date: Fri, 7 Sep 2018 14:02:44 +0200
Subject: [PATCH] Pull cache-from images on gcb

Fixes #936

Signed-off-by: David Gageot <david@gageot.net>
---
 pkg/skaffold/build/gcb/cloud_build.go         | 26 --------
 pkg/skaffold/build/gcb/desc.go                | 60 +++++++++++++++++++
 .../gcb/{cloud_build_test.go => desc_test.go} | 32 ++++++++++
 3 files changed, 92 insertions(+), 26 deletions(-)
 create mode 100644 pkg/skaffold/build/gcb/desc.go
 rename pkg/skaffold/build/gcb/{cloud_build_test.go => desc_test.go} (69%)

diff --git a/pkg/skaffold/build/gcb/cloud_build.go b/pkg/skaffold/build/gcb/cloud_build.go
index aa5ef05aaf5..7adcd2ad15c 100644
--- a/pkg/skaffold/build/gcb/cloud_build.go
+++ b/pkg/skaffold/build/gcb/cloud_build.go
@@ -158,32 +158,6 @@ watch:
 	return newTag, nil
 }
 
-func (b *Builder) buildDescription(artifact *v1alpha2.Artifact, bucket, object string) *cloudbuild.Build {
-	args := append([]string{"build", "--tag", artifact.ImageName, "-f", artifact.DockerArtifact.DockerfilePath})
-	args = append(args, docker.GetBuildArgs(artifact.DockerArtifact)...)
-	args = append(args, ".")
-
-	return &cloudbuild.Build{
-		LogsBucket: bucket,
-		Source: &cloudbuild.Source{
-			StorageSource: &cloudbuild.StorageSource{
-				Bucket: bucket,
-				Object: object,
-			},
-		},
-		Steps: []*cloudbuild.BuildStep{{
-			Name: b.DockerImage,
-			Args: args,
-		}},
-		Images: []string{artifact.ImageName},
-		Options: &cloudbuild.BuildOptions{
-			DiskSizeGb:  b.DiskSizeGb,
-			MachineType: b.MachineType,
-		},
-		Timeout: b.Timeout,
-	}
-}
-
 func getBuildID(op *cloudbuild.Operation) (string, error) {
 	if op.Metadata == nil {
 		return "", errors.New("missing Metadata in operation")
diff --git a/pkg/skaffold/build/gcb/desc.go b/pkg/skaffold/build/gcb/desc.go
new file mode 100644
index 00000000000..9ced4e2a5bd
--- /dev/null
+++ b/pkg/skaffold/build/gcb/desc.go
@@ -0,0 +1,60 @@
+/*
+Copyright 2018 The Skaffold Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package gcb
+
+import (
+	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/docker"
+	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/schema/v1alpha2"
+	cloudbuild "google.golang.org/api/cloudbuild/v1"
+)
+
+func (b *Builder) buildDescription(artifact *v1alpha2.Artifact, bucket, object string) *cloudbuild.Build {
+	var steps []*cloudbuild.BuildStep
+
+	for _, cacheFrom := range artifact.DockerArtifact.CacheFrom {
+		steps = append(steps, &cloudbuild.BuildStep{
+			Name: b.DockerImage,
+			Args: []string{"pull", cacheFrom},
+		})
+	}
+
+	args := append([]string{"build", "--tag", artifact.ImageName, "-f", artifact.DockerArtifact.DockerfilePath})
+	args = append(args, docker.GetBuildArgs(artifact.DockerArtifact)...)
+	args = append(args, ".")
+
+	steps = append(steps, &cloudbuild.BuildStep{
+		Name: b.DockerImage,
+		Args: args,
+	})
+
+	return &cloudbuild.Build{
+		LogsBucket: bucket,
+		Source: &cloudbuild.Source{
+			StorageSource: &cloudbuild.StorageSource{
+				Bucket: bucket,
+				Object: object,
+			},
+		},
+		Steps:  steps,
+		Images: []string{artifact.ImageName},
+		Options: &cloudbuild.BuildOptions{
+			DiskSizeGb:  b.DiskSizeGb,
+			MachineType: b.MachineType,
+		},
+		Timeout: b.Timeout,
+	}
+}
diff --git a/pkg/skaffold/build/gcb/cloud_build_test.go b/pkg/skaffold/build/gcb/desc_test.go
similarity index 69%
rename from pkg/skaffold/build/gcb/cloud_build_test.go
rename to pkg/skaffold/build/gcb/desc_test.go
index 0e1c3062b7b..ab51863302a 100644
--- a/pkg/skaffold/build/gcb/cloud_build_test.go
+++ b/pkg/skaffold/build/gcb/desc_test.go
@@ -71,3 +71,35 @@ func TestBuildDescription(t *testing.T) {
 
 	testutil.CheckDeepEqual(t, expected, *desc)
 }
+
+func TestPullCacheFrom(t *testing.T) {
+	artifact := &v1alpha2.Artifact{
+		ImageName: "nginx",
+		ArtifactType: v1alpha2.ArtifactType{
+			DockerArtifact: &v1alpha2.DockerArtifact{
+				DockerfilePath: "Dockerfile",
+				CacheFrom:      []string{"from/image1", "from/image2"},
+			},
+		},
+	}
+
+	builder := Builder{
+		GoogleCloudBuild: &v1alpha2.GoogleCloudBuild{
+			DockerImage: "docker/docker",
+		},
+	}
+	desc := builder.buildDescription(artifact, "bucket", "object")
+
+	expected := []*cloudbuild.BuildStep{{
+		Name: "docker/docker",
+		Args: []string{"pull", "from/image1"},
+	}, {
+		Name: "docker/docker",
+		Args: []string{"pull", "from/image2"},
+	}, {
+		Name: "docker/docker",
+		Args: []string{"build", "--tag", "nginx", "-f", "Dockerfile", "--cache-from", "from/image1", "--cache-from", "from/image2", "."},
+	}}
+
+	testutil.CheckDeepEqual(t, expected, desc.Steps)
+}