[FAB-3118] pull ccenv image at runtime

The current code requires the CORE_CHAINCODE_BUILDER image to
be pre-pulled down from dockerhub or chaincode building will
fail.  This patch adds the docker-client intelligence to
check whether the image is present.  If it finds that it is
not present, it will try to pull the image from dockerhub.

Change-Id: I95b6bcd0f1b1beb2edee7f0b542f90f5fb9eabc7
Signed-off-by: Greg Haskins <gregory.haskins@gmail.com>

core/chaincode/platforms/util/utils.go

@@ -155,6 +155,21 @@ func DockerBuild(opts DockerBuildOptions) error {
 		}
 	}
 
+	logger.Debugf("Attempting build with image %s", opts.Image)
+
+	//-----------------------------------------------------------------------------------
+	// Ensure the image exists locally, or pull it from a registry if it doesn't
+	//-----------------------------------------------------------------------------------
+	_, err = client.InspectImage(opts.Image)
+	if err != nil {
+		logger.Debugf("Image %s does not exist locally, attempt pull", opts.Image)
+
+		err = client.PullImage(docker.PullImageOptions{Repository: opts.Image}, docker.AuthConfiguration{})
+		if err != nil {
+			return fmt.Errorf("Failed to pull %s: %s", opts.Image, err)
+		}
+	}
+
 	//-----------------------------------------------------------------------------------
 	// Create an ephemeral container, armed with our Env/Cmd
 	//-----------------------------------------------------------------------------------

core/chaincode/platforms/util/utils_test.go

@@ -23,7 +23,16 @@ import (
 	"testing"
 	"time"
 
+	"archive/tar"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
 	"github.com/hyperledger/fabric/common/util"
+	"github.com/hyperledger/fabric/core/config"
+	cutil "github.com/hyperledger/fabric/core/container/util"
+	"github.com/spf13/viper"
 )
 
 // TestHashContentChange changes a random byte in a content and checks for hash change
@@ -187,3 +196,49 @@ func TestHashSameDir(t *testing.T) {
 		t.Error("Hash should be same across multiple downloads")
 	}
 }
+
+func TestDockerPull(t *testing.T) {
+	codepackage, output := io.Pipe()
+	go func() {
+		tw := tar.NewWriter(output)
+
+		tw.Close()
+		output.Close()
+	}()
+
+	binpackage := bytes.NewBuffer(nil)
+
+	// Perform a nop operation within a fixed target.  We choose 1.0.0-alpha2 because we know it's
+	// published and available.  Ideally we could choose something that we know is both multi-arch
+	// and ok to delete prior to executing DockerBuild.  This would ensure that we exercise the
+	// image pull logic.  However, no suitable target exists that meets all the criteria.  Therefore
+	// we settle on using a known released image.  We don't know if the image is already
+	// downloaded per se, and we don't want to explicitly delete this particular image first since
+	// it could be in use legitimately elsewhere.  Instead, we just know that this should always
+	// work and call that "close enough".
+	//
+	// Future considerations: publish a known dummy image that is multi-arch and free to randomly
+	// delete, and use that here instead.
+	err := DockerBuild(DockerBuildOptions{
+		Image:        cutil.ParseDockerfileTemplate("hyperledger/fabric-ccenv:$(ARCH)-1.0.0-alpha2"),
+		Cmd:          "/bin/true",
+		InputStream:  codepackage,
+		OutputStream: binpackage,
+	})
+	if err != nil {
+		t.Errorf("Error during build: %s", err)
+	}
+}
+
+func TestMain(m *testing.M) {
+	viper.SetConfigName("core")
+	viper.SetEnvPrefix("CORE")
+	config.AddDevConfigPath(nil)
+	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+	viper.AutomaticEnv()
+	if err := viper.ReadInConfig(); err != nil {
+		fmt.Printf("could not read config %s\n", err)
+		os.Exit(-1)
+	}
+	os.Exit(m.Run())
+}

core/container/util/dockerutil.go

@@ -56,7 +56,7 @@ func getArch() string {
 	}
 }
 
-func parseDockerfileTemplate(template string) string {
+func ParseDockerfileTemplate(template string) string {
 	r := strings.NewReplacer(
 		"$(ARCH)", getArch(),
 		"$(PROJECT_VERSION)", metadata.Version,
@@ -68,5 +68,5 @@ func parseDockerfileTemplate(template string) string {
 }
 
 func GetDockerfileFromConfig(path string) string {
-	return parseDockerfileTemplate(viper.GetString(path))
+	return ParseDockerfileTemplate(viper.GetString(path))
 }

core/container/util/dockerutil_test.go

@@ -26,7 +26,7 @@ import (
 
 func TestUtil_DockerfileTemplateParser(t *testing.T) {
 	expected := "FROM foo:" + getArch() + "-" + metadata.Version
-	actual := parseDockerfileTemplate("FROM foo:$(ARCH)-$(PROJECT_VERSION)")
+	actual := ParseDockerfileTemplate("FROM foo:$(ARCH)-$(PROJECT_VERSION)")
 	assert.Equal(t, expected, actual, "Error parsing Dockerfile Template. Expected \"%s\", got \"%s\"",
 		expected, actual)
 }