feat(build): Do not build images twice with the same content

Author: asalkeld

pkg/build/build.go

@@ -29,6 +29,11 @@ import (
 	"github.com/nitrictech/cli/pkg/target"
 )
 
+func dynamicDockerfile(dir, name string) (*os.File, error) {
+	// create a more stable file name for the hashing
+	return os.CreateTemp(dir, "nitric.dynamic.Dockerfile.*")
+}
+
 func Create(s *stack.Stack, t *target.Target) error {
 	cr, err := containerengine.Discover()
 	if err != nil {
@@ -44,7 +49,7 @@ func Create(s *stack.Stack, t *target.Target) error {
 			}
 		}
 
-		fh, err := os.CreateTemp(s.Dir, "Dockerfile.*")
+		fh, err := dynamicDockerfile(s.Dir, f.Name)
 		if err != nil {
 			return err
 		}
@@ -95,7 +100,7 @@ func CreateBaseDev(s *stack.Stack) error {
 			continue
 		}
 
-		f, err := os.CreateTemp(s.Dir, fmt.Sprintf("%s.*.dockerfile", lang))
+		f, err := dynamicDockerfile(s.Dir, f.Name)
 		if err != nil {
 			return err
 		}

pkg/cmd/deployment/root.go

@@ -53,7 +53,11 @@ var deploymentApplyCmd = &cobra.Command{
 	Short: "Create or Update a new application deployment",
 	Long:  `Applies a Nitric application deployment.`,
 	Example: `nitric deployment apply
+
+# When using a nitric.yaml
 nitric deployment apply -n prod-aws -s ../project/ -t prod
+
+# When using code-as-config, specify the functions.
 nitric deployment apply -n prod-aws -s ../project/ -t prod "functions/*.ts"
 		`,
 	Run: func(cmd *cobra.Command, args []string) {

pkg/cmd/run/root.go

@@ -39,7 +39,7 @@ var runCmd = &cobra.Command{
 	Short: "run a nitric stack",
 	Long: `Run a nitric stack locally for development or testing
 `,
-	Example: `nitric run -s projectX "functions/*.ts"`,
+	Example: `nitric run -s ../projectX "functions/*.ts"`,
 	Run: func(cmd *cobra.Command, args []string) {
 		term := make(chan os.Signal, 1)
 		signal.Notify(term, os.Interrupt, syscall.SIGTERM)

pkg/containerengine/docker.go

@@ -19,6 +19,8 @@ package containerengine
 import (
 	"bufio"
 	"context"
+	"crypto/md5"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -93,23 +95,64 @@ func tarContextDir(relDockerfile, contextDir string, extraExcludes []string) (io
 	})
 }
 
+func imageNameFromBuildContext(dockerfile, srcPath, imageTag string, excludes []string) (string, error) {
+	var buildContext io.ReadCloser
+	var err error
+	if strings.Contains(dockerfile, "nitric.dynamic.") {
+		// don't include the dynamic dockerfile as the timestamp on the file will cause it to have a different hash.
+		buildContext, err = tarContextDir("", srcPath, append(excludes, dockerfile))
+	} else {
+		buildContext, err = tarContextDir(dockerfile, srcPath, excludes)
+	}
+	if err != nil {
+		return "", err
+	}
+
+	hash := md5.New()
+	_, err = io.Copy(hash, buildContext)
+	if err != nil {
+		return "", err
+	}
+
+	imageName := imageTag
+	if strings.Contains(imageTag, ":") {
+		imageName = strings.Split(imageTag, ":")[0]
+	}
+
+	return imageName + ":" + hex.EncodeToString(hash.Sum(nil)), nil
+}
+
 func (d *docker) Build(dockerfile, srcPath, imageTag string, buildArgs map[string]string, excludes []string) error {
 	ctx, cancel := context.WithTimeout(context.Background(), buildTimeout())
 	defer cancel()
 
-	dockerBuildContext, err := tarContextDir(dockerfile, srcPath, excludes)
+	imageTagWithHash, err := imageNameFromBuildContext(dockerfile, srcPath, imageTag, excludes)
+	if err != nil {
+		return err
+	}
+
+	buildContext, err := tarContextDir(dockerfile, srcPath, excludes)
 	if err != nil {
 		return err
 	}
+
+	// try and find an existing image with this hash.
+	listOpts := types.ImageListOptions{Filters: filters.NewArgs()}
+	listOpts.Filters.Add("reference", imageTagWithHash)
+	imageSummaries, err := d.cli.ImageList(ctx, listOpts)
+	if err == nil && len(imageSummaries) > 0 {
+		return nil
+	}
+
 	opts := types.ImageBuildOptions{
 		SuppressOutput: false,
 		Dockerfile:     dockerfile,
-		Tags:           []string{imageTag},
+		Tags:           []string{imageTag, imageTagWithHash},
 		Remove:         true,
 		ForceRemove:    true,
 		PullParent:     true,
 	}
-	res, err := d.cli.ImageBuild(ctx, dockerBuildContext, opts)
+	res, err := d.cli.ImageBuild(ctx, buildContext, opts)
 	if err != nil {
 		return err
 	}

pkg/stack/options.go

@@ -35,7 +35,7 @@ var (
 
 func wrapStatError(err error) error {
 	if os.IsNotExist(err) {
-		return errors.WithMessage(err, "Please provide the correct path to the stack (eg. -s ./nitric.yaml)")
+		return errors.WithMessage(err, "Please provide the correct path to the stack (eg. -s ../projectX)")
 	}
 	if os.IsPermission(err) {
 		return errors.WithMessagef(err, "Please make sure that %s has the correct permissions", stackPath)