feat: add support for DockerfileInline

As nerdctl currently uses "nerdctl build" to build the service
images, write the inline file to a temporary file and use "-f"
to specify the temporary dockerfile.

Signed-off-by: Tushar Gupta <[email protected]>

Author: tushar5526

cmd/nerdctl/compose/compose_build_linux_test.go

@@ -39,6 +39,7 @@ func TestComposeBuild(t *testing.T) {
 		// Make sure we shard the image name to something unique to the test to avoid conflicts with other tests
 		imageSvc0 := data.Identifier("svc0")
 		imageSvc1 := data.Identifier("svc1")
+		imageSvc2 := data.Identifier("svc2")
 
 		// We are not going to run them, so, ports conflicts should not matter here
 		dockerComposeYAML := fmt.Sprintf(`
@@ -51,14 +52,21 @@ services:
   svc1:
     build: .
     image: %s
-`, imageSvc0, imageSvc1)
+  svc2:
+    image: %s
+    build:
+      context: .
+      dockerfile_inline: |
+        FROM %s
+`, imageSvc0, imageSvc1, imageSvc2, testutil.CommonImage)
 
 		data.Temp().Save(dockerComposeYAML, "compose.yaml")
 		data.Temp().Save(dockerfile, "Dockerfile")
 
 		data.Labels().Set("composeYaml", data.Temp().Path("compose.yaml"))
 		data.Labels().Set("imageSvc0", imageSvc0)
 		data.Labels().Set("imageSvc1", imageSvc1)
+		data.Labels().Set("imageSvc2", imageSvc2)
 	}
 
 	testCase.SubTests = []*test.Case{
@@ -76,22 +84,41 @@ services:
 					Output: expect.All(
 						expect.Contains(data.Labels().Get("imageSvc0")),
 						expect.DoesNotContain(data.Labels().Get("imageSvc1")),
+						expect.DoesNotContain(data.Labels().Get("imageSvc2")),
+					),
+				}
+			},
+		},
+		{
+			Description: "build svc2",
+			NoParallel:  true,
+			Setup: func(data test.Data, helpers test.Helpers) {
+				helpers.Ensure("compose", "-f", data.Labels().Get("composeYaml"), "build", "svc2")
+			},
+
+			Command: test.Command("images"),
+
+			Expected: func(data test.Data, helpers test.Helpers) *test.Expected {
+				return &test.Expected{
+					Output: expect.All(
+						expect.Contains(data.Labels().Get("imageSvc2")),
+						expect.DoesNotContain(data.Labels().Get("imageSvc1")),
 					),
 				}
 			},
 		},
 		{
-			Description: "build svc0 and svc1",
+			Description: "build svc0, svc1, svc2",
 			NoParallel:  true,
 			Setup: func(data test.Data, helpers test.Helpers) {
-				helpers.Ensure("compose", "-f", data.Labels().Get("composeYaml"), "build", "svc0", "svc1")
+				helpers.Ensure("compose", "-f", data.Labels().Get("composeYaml"), "build", "svc0", "svc1", "svc2")
 			},
 
 			Command: test.Command("images"),
 
 			Expected: func(data test.Data, helpers test.Helpers) *test.Expected {
 				return &test.Expected{
-					Output: expect.Contains(data.Labels().Get("imageSvc0"), data.Labels().Get("imageSvc1")),
+					Output: expect.Contains(data.Labels().Get("imageSvc0"), data.Labels().Get("imageSvc1"), data.Labels().Get("imageSvc2")),
 				}
 			},
 		},
@@ -122,7 +149,7 @@ services:
 
 	testCase.Cleanup = func(data test.Data, helpers test.Helpers) {
 		if data.Labels().Get("imageSvc0") != "" {
-			helpers.Anyhow("rmi", data.Labels().Get("imageSvc0"), data.Labels().Get("imageSvc1"))
+			helpers.Anyhow("rmi", data.Labels().Get("imageSvc0"), data.Labels().Get("imageSvc1"), data.Labels().Get("imageSvc2"))
 		}
 	}
 

pkg/composer/build.go

@@ -63,6 +63,23 @@ func (c *Composer) buildServiceImage(ctx context.Context, image string, b *servi
 	if bo.Progress != "" {
 		args = append(args, "--progress="+bo.Progress)
 	}
+
+	if b.DockerfileInline != "" {
+		// if DockerfileInline is specified, write it to a temporary file
+		// and use -f flag to use that docker file with project's ctxdir
+		tmpFile, err := os.CreateTemp("", "inline-dockerfile-*.Dockerfile")
+		if err != nil {
+			return fmt.Errorf("failed to create temp file for DockerfileInline: %w", err)
+		}
+		defer os.Remove(tmpFile.Name())
+		defer tmpFile.Close()
+
+		if _, err := tmpFile.Write([]byte(b.DockerfileInline)); err != nil {
+			return fmt.Errorf("failed to write DockerfileInline: %w", err)
+		}
+		b.BuildArgs = append(b.BuildArgs, "-f="+tmpFile.Name())
+	}
+
 	args = append(args, b.BuildArgs...)
 
 	cmd := c.createNerdctlCmd(ctx, append([]string{"build"}, args...)...)

pkg/composer/serviceparser/build.go

@@ -34,7 +34,7 @@ import (
 
 func parseBuildConfig(c *types.BuildConfig, project *types.Project, imageName string) (*Build, error) {
 	if unknown := reflectutil.UnknownNonEmptyFields(c,
-		"Context", "Dockerfile", "Args", "CacheFrom", "Target", "Labels", "Secrets", "AdditionalContexts",
+		"Context", "Dockerfile", "Args", "CacheFrom", "Target", "Labels", "Secrets", "DockerfileInline", "AdditionalContexts",
 	); len(unknown) > 0 {
 		log.L.Warnf("Ignoring: build: %+v", unknown)
 	}
@@ -60,6 +60,10 @@ func parseBuildConfig(c *types.BuildConfig, project *types.Project, imageName st
 		}
 	}
 
+	if c.DockerfileInline != "" {
+		b.DockerfileInline = c.DockerfileInline
+	}
+
 	for k, v := range c.Args {
 		if v == nil {
 			b.BuildArgs = append(b.BuildArgs, "--build-arg="+k)

pkg/composer/serviceparser/build_test.go

@@ -18,6 +18,7 @@ package serviceparser
 
 import (
 	"runtime"
+	"strings"
 	"testing"
 
 	"gotest.tools/v3/assert"
@@ -54,6 +55,12 @@ services:
           target: tgt_secret
         - simple_secret
         - absolute_secret
+  baz:
+    image: bazimg
+    build:
+      context: ./bazctx
+      dockerfile_inline: |
+       FROM random
 secrets:
   src_secret:
     file: test_secret1
@@ -95,4 +102,17 @@ secrets:
 	assert.Assert(t, in(bar.Build.BuildArgs, "--secret=id=tgt_secret,src="+secretPath+"/test_secret1"))
 	assert.Assert(t, in(bar.Build.BuildArgs, "--secret=id=simple_secret,src="+secretPath+"/test_secret2"))
 	assert.Assert(t, in(bar.Build.BuildArgs, "--secret=id=absolute_secret,src=/tmp/absolute_secret"))
+
+	bazSvc, err := project.GetService("baz")
+	assert.NilError(t, err)
+
+	baz, err := Parse(project, bazSvc)
+	assert.NilError(t, err)
+
+	t.Logf("baz: %+v", baz)
+	t.Logf("baz.Build.BuildArgs: %+v", baz.Build.BuildArgs)
+	t.Logf("baz.Build.DockerfileInline: %q", baz.Build.DockerfileInline)
+	assert.Assert(t, func() bool {
+		return strings.TrimSpace(baz.Build.DockerfileInline) == "FROM random"
+	}())
 }

pkg/composer/serviceparser/serviceparser.go

@@ -195,8 +195,9 @@ type Container struct {
 }
 
 type Build struct {
-	Force     bool     // force build even if already present
-	BuildArgs []string // {"-t", "example.com/foo", "--target", "foo", "/path/to/ctx"}
+	Force            bool     // force build even if already present
+	BuildArgs        []string // {"-t", "example.com/foo", "--target", "foo", "/path/to/ctx"}
+	DockerfileInline string   // store contents of dockerfile_inline field is specified
 	// TODO: call BuildKit API directly without executing `nerdctl build`
 }