feat: base image flag for host builds

cmd/build.go

@@ -69,8 +69,8 @@ EXAMPLES
 `,
 		SuggestFor: []string{"biuld", "buidl", "built"},
 		PreRunE: bindEnv("image", "path", "builder", "registry", "confirm",
-			"push", "builder-image", "platform", "verbose", "build-timestamp",
-			"registry-insecure", "username", "password", "token"),
+			"push", "builder-image", "base-image", "platform", "verbose",
+			"build-timestamp", "registry-insecure", "username", "password", "token"),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runBuild(cmd, args, newClient)
 		},
@@ -110,6 +110,8 @@ EXAMPLES
 	builderImage := f.Build.BuilderImages[f.Build.Builder]
 	cmd.Flags().StringP("builder-image", "", builderImage,
 		"Specify a custom builder image for use by the builder other than its default. ($FUNC_BUILDER_IMAGE)")
+	cmd.Flags().StringP("base-image", "", f.Build.BaseImage,
+		"Override the base image for your function (host builder only)")
 	cmd.Flags().StringP("image", "i", f.Image,
 		"Full image name in the form [registry]/[namespace]/[name]:[tag] (optional). This option takes precedence over --registry ($FUNC_IMAGE)")
 
@@ -223,6 +225,10 @@ type buildConfig struct {
 	// image name derivation based on registry and function name)
 	Image string
 
+	// BaseImage is an image to build a function upon (host builder only)
+	// TODO: gauron99 -- make option to add a path to dockerfile ?
+	BaseImage string
+
 	// Path of the function implementation on local disk. Defaults to current
 	// working directory of the process.
 	Path string
@@ -260,6 +266,7 @@ func newBuildConfig() buildConfig {
 			RegistryInsecure: viper.GetBool("registry-insecure"),
 		},
 		BuilderImage:  viper.GetString("builder-image"),
+		BaseImage:     viper.GetString("base-image"),
 		Image:         viper.GetString("image"),
 		Path:          viper.GetString("path"),
 		Platform:      viper.GetString("platform"),
@@ -281,6 +288,7 @@ func (c buildConfig) Configure(f fn.Function) fn.Function {
 		f.Build.BuilderImages[f.Build.Builder] = c.BuilderImage
 	}
 	f.Image = c.Image
+	f.Build.BaseImage = c.BaseImage
 	// Path, Platform and Push are not part of a function's state.
 	return f
 }
@@ -360,6 +368,10 @@ func (c buildConfig) Validate() (err error) {
 		return
 	}
 
+	// BaseImage is only supported with the host builder
+	if c.BaseImage != "" && c.Builder != "host" {
+		err = errors.New("only host builds support specifying the base image")
+	}
 	return
 }
 

cmd/build_test.go

@@ -95,6 +95,12 @@ func TestBuild_Authentication(t *testing.T) {
 	testAuthentication(NewBuildCmd, t)
 }
 
+// TestBuild_BaseImage ensures that base image is used only with the right
+// builders and propagates into f.Build.BaseImage
+func TestBuild_BaseImage(t *testing.T) {
+	testBaseImage(NewBuildCmd, t)
+}
+
 // TestBuild_Push ensures that the build command properly pushes and respects
 // the --push flag.
 // - Push triggered after a successful build

cmd/deploy.go

@@ -128,7 +128,11 @@ EXAMPLES
 
 `,
 		SuggestFor: []string{"delpoy", "deplyo"},
-		PreRunE:    bindEnv("build", "build-timestamp", "builder", "builder-image", "confirm", "domain", "env", "git-branch", "git-dir", "git-url", "image", "namespace", "path", "platform", "push", "pvc-size", "service-account", "registry", "registry-insecure", "remote", "username", "password", "token", "verbose", "remote-storage-class"),
+		PreRunE: bindEnv("build", "build-timestamp", "builder", "builder-image",
+			"base-image", "confirm", "domain", "env", "git-branch", "git-dir",
+			"git-url", "image", "namespace", "path", "platform", "push", "pvc-size",
+			"service-account", "registry", "registry-insecure", "remote",
+			"username", "password", "token", "verbose", "remote-storage-class"),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runDeploy(cmd, newClient)
 		},
@@ -163,6 +167,8 @@ EXAMPLES
 	builderImage := f.Build.BuilderImages[f.Build.Builder]
 	cmd.Flags().String("builder-image", builderImage,
 		"Specify a custom builder image for use by the builder other than its default. ($FUNC_BUILDER_IMAGE)")
+	cmd.Flags().StringP("base-image", "", f.Build.BaseImage,
+		"Override the base image for your function (host builder only)")
 	cmd.Flags().StringP("image", "i", f.Image,
 		"Full image name in the form [registry]/[namespace]/[name]:[tag]@[digest]. This option takes precedence over --registry. Specifying digest is optional, but if it is given, 'build' and 'push' phases are disabled. ($FUNC_IMAGE)")
 

cmd/deploy_test.go

@@ -2170,3 +2170,75 @@ func Test_isDigested(t *testing.T) {
 		t.Fatal("did not report image reference has digest")
 	}
 }
+
+func TestDeploy_BaseImage(t *testing.T) {
+	testBaseImage(NewDeployCmd, t)
+}
+
+func testBaseImage(cmdFn commandConstructor, t *testing.T) {
+	const baseImage = "example.com/repo/baseImage"
+	tests := []struct {
+		name    string
+		runtime string
+		builder string
+		expErr  bool
+	}{
+		{
+			name:    "should-succeed: python-runtime with host-builder",
+			runtime: "python",
+			builder: "host",
+		},
+		{
+			name:    "should-succeed: go-runtime with host-builder",
+			runtime: "go",
+			builder: "host",
+		},
+		{
+			name:    "should-fail: python-runtime with pack-builder",
+			runtime: "python",
+			builder: "pack",
+			expErr:  true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			root := FromTempDirectory(t)
+
+			// func init
+			f := fn.Function{Runtime: tt.runtime, Root: root}
+			_, err := fn.New().Init(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			//create cmd
+			cmd := cmdFn(NewTestClient(
+				fn.WithBuilder(mock.NewBuilder()),
+				fn.WithDeployer(mock.NewDeployer()),
+				fn.WithRegistry(TestRegistry),
+			))
+
+			// create flags for cmd
+			args := []string{
+				fmt.Sprintf("--builder=%s", tt.builder),
+				fmt.Sprintf("--base-image=%s", baseImage),
+			}
+
+			cmd.SetArgs(args)
+			err = cmd.Execute()
+
+			// ASSERT
+
+			// got error but expected success
+			if err != nil && !tt.expErr {
+				err = fmt.Errorf("Expected the test to succeed but instead got: %w", err)
+				t.Fatal(err)
+			}
+
+			// succeeded but expected fail
+			if err == nil && tt.expErr {
+				t.Fatal(fmt.Errorf("Expected error but test succeeded"))
+			}
+		})
+	}
+}

cmd/run.go

@@ -77,7 +77,9 @@ EXAMPLES
 	  $ {{rootCmdUse}} run --json
 `,
 		SuggestFor: []string{"rnu"},
-		PreRunE:    bindEnv("build", "builder", "builder-image", "confirm", "container", "env", "image", "path", "registry", "start-timeout", "verbose", "address", "json"),
+		PreRunE: bindEnv("build", "builder", "builder-image", "base-image",
+			"confirm", "container", "env", "image", "path", "registry",
+			"start-timeout", "verbose", "address", "json"),
 		RunE: func(cmd *cobra.Command, _ []string) error {
 			return runRun(cmd, newClient)
 		},
@@ -109,6 +111,8 @@ EXAMPLES
 	builderImage := f.Build.BuilderImages[f.Build.Builder]
 	cmd.Flags().String("builder-image", builderImage,
 		"Specify a custom builder image for use by the builder other than its default. ($FUNC_BUILDER_IMAGE)")
+	cmd.Flags().StringP("base-image", "", f.Build.BaseImage,
+		"Override the base image for your function (host builder only)")
 	cmd.Flags().StringP("image", "i", f.Image,
 		"Full image name in the form [registry]/[namespace]/[name]:[tag]. This option takes precedence over --registry. Specifying tag is optional. ($FUNC_IMAGE)")
 	cmd.Flags().StringArrayP("env", "e", []string{},

cmd/run_test.go

@@ -515,3 +515,89 @@ func TestRun_Address(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+// TestRun_BaseImage ensures that running func run --base-image with various
+// other
+func TestRun_BaseImage(t *testing.T) {
+	const baseImage = "example.com/repo/baseImage"
+	tests := []struct {
+		name        string
+		runtime     string
+		builder     string
+		expectError bool
+	}{
+		{
+			name:    "should-succeed: python-runtime with host-builder",
+			runtime: "python",
+			builder: "host",
+		},
+		{
+			name:    "should-succeed: go-runtime with host-builder",
+			runtime: "go",
+			builder: "host",
+		},
+		{
+			name:        "should-fail: python-runtime with pack-builder",
+			runtime:     "python",
+			builder:     "pack",
+			expectError: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			root := FromTempDirectory(t)
+			runner := mock.NewRunner()
+
+			runner.RunFn = func(_ context.Context, f fn.Function, _ string, _ time.Duration) (*fn.Job, error) {
+				errs := make(chan error, 1)
+				stop := func() error { return nil }
+				return fn.NewJob(f, "127.0.0.1", "8080", errs, stop, false)
+			}
+
+			builder := mock.NewBuilder()
+			//if tt.expectError {
+			//	builder.BuildFn = func(f fn.Function) error { return fmt.Errorf("expected error") }
+			//}
+
+			cmd := NewRunCmd(NewTestClient(
+				fn.WithRunner(runner),
+				fn.WithBuilder(builder),
+				fn.WithRegistry(TestRegistry),
+			))
+			args := []string{"--build=true", fmt.Sprintf("--builder=%s", tt.builder), fmt.Sprintf("--base-image=%s", baseImage)}
+			cmd.SetArgs(args)
+
+			// set test case's function instance
+			_, err := fn.New().Init(fn.Function{Root: root, Runtime: tt.runtime})
+			if err != nil {
+				t.Fatal(err)
+			}
+			ctx, cancel := context.WithCancel(context.Background())
+			runErrCh := make(chan error, 1)
+			go func() {
+				t0 := tt // capture tt into closure
+				_, err := cmd.ExecuteContextC(ctx)
+				if err != nil && t0.expectError {
+					// This is an expected error, so simply continue execution ignoring
+					// the error (send nil on the channel to release the parent routine
+					runErrCh <- nil
+					return
+				} else if err != nil {
+					runErrCh <- err // error not expected
+					return
+				}
+
+				// No errors, but an error was expected:
+				if t0.expectError {
+					runErrCh <- fmt.Errorf("Expected error but got '%v'\n", err)
+				}
+				close(runErrCh) // release the waiting parent process
+			}()
+			cancel() // trigger the return of cmd.ExecuteContextC in the routine
+			<-ctx.Done()
+			if err := <-runErrCh; err != nil { // wait for completion of assertions
+				t.Fatal(err)
+			}
+		})
+	}
+}

docs/reference/func_build.md

@@ -57,6 +57,7 @@ func build
 ### Options
 
 ```
+      --base-image string      Override the base image for your function (host builder only)
       --build-timestamp        Use the actual time as the created time for the docker image. This is only useful for buildpacks builder.
   -b, --builder string         Builder to use when creating the function's container. Currently supported builders are "host", "pack" and "s2i". ($FUNC_BUILDER) (default "pack")
       --builder-image string   Specify a custom builder image for use by the builder other than its default. ($FUNC_BUILDER_IMAGE)

docs/reference/func_deploy.md

@@ -113,6 +113,7 @@ func deploy
 ### Options
 
 ```
+      --base-image string             Override the base image for your function (host builder only)
       --build string[="true"]         Build the function. [auto|true|false]. ($FUNC_BUILD) (default "auto")
       --build-timestamp               Use the actual time as the created time for the docker image. This is only useful for buildpacks builder.
   -b, --builder string                Builder to use when creating the function's container. Currently supported builders are "host", "pack" and "s2i". (default "pack")

docs/reference/func_run.md

@@ -67,6 +67,7 @@ func run
 
 ```
       --address string          Interface and port on which to bind and listen. Default is 127.0.0.1:8080, or an available port if 8080 is not available. ($FUNC_ADDRESS)
+      --base-image string       Override the base image for your function (host builder only)
       --build string[="true"]   Build the function. [auto|true|false]. ($FUNC_BUILD) (default "auto")
   -b, --builder string          Builder to use when creating the function's container. Currently supported builders are "host", "pack" and "s2i". (default "pack")
       --builder-image string    Specify a custom builder image for use by the builder other than its default. ($FUNC_BUILDER_IMAGE)

pkg/functions/function.go

@@ -152,6 +152,9 @@ type BuildSpec struct {
 	// in .func/built-image
 	Image string `yaml:"-"`
 
+	// BaseImage defines an override for the function to be built upon (host bulder only)
+	BaseImage string `yaml:"baseImage,omitempty"`
+
 	// Mounts used in build phase. This is useful in particular for paketo bindings.
 	Mounts []MountSpec `yaml:"volumes,omitempty"`
 }

pkg/oci/builder.go

@@ -64,7 +64,7 @@ type languageBuilder interface {
 	// Base returns the base image (if any) to use.  Ideally this is a
 	// multi-arch base image with a corresponding platform image for
 	// each requested to be built.
-	Base() string
+	Base(customBase string) string
 
 	// WriteShared layers (not platform-specific) which need to be genearted
 	// on demand per language, such as shared dependencies.
@@ -568,12 +568,13 @@ func newCertsTarball(source, target string, verbose bool) error {
 // Its layers are automatically downloaded into the local cache if this is
 // the first fetch and their blobs linked into the final OCI image.
 func pullBase(job buildJob, p v1.Platform) (image v1.Image, err error) {
-	if job.languageBuilder.Base() == "" {
+	baseImage := job.function.Build.BaseImage
+	if job.languageBuilder.Base(baseImage) == "" {
 		return // FROM SCRATCH
 	}
 
 	// Parse the base into a reference
-	ref, err := name.ParseReference(job.languageBuilder.Base())
+	ref, err := name.ParseReference(job.languageBuilder.Base(baseImage))
 	if err != nil {
 		return
 	}

pkg/oci/builder_test.go

@@ -461,7 +461,7 @@ func TestBuilder_StaticEnvs(t *testing.T) {
 // OCI builder for each language, and can be overridden for testing
 type TestLanguageBuilder struct {
 	BaseInvoked bool
-	BaseFn      func() string
+	BaseFn      func(customImage string) string
 
 	WriteSharedInvoked bool
 	WriteSharedFn      func(buildJob) ([]imageLayer, error)
@@ -475,7 +475,7 @@ type TestLanguageBuilder struct {
 
 func NewTestLanguageBuilder() *TestLanguageBuilder {
 	return &TestLanguageBuilder{
-		BaseFn:          func() string { return "" },
+		BaseFn:          func(customImage string) string { return "" },
 		WriteSharedFn:   func(buildJob) ([]imageLayer, error) { return []imageLayer{}, nil },
 		WritePlatformFn: func(buildJob, v1.Platform) ([]imageLayer, error) { return []imageLayer{}, nil },
 		ConfigureFn: func(buildJob, v1.Platform, v1.ConfigFile) (v1.ConfigFile, error) {
@@ -484,9 +484,9 @@ func NewTestLanguageBuilder() *TestLanguageBuilder {
 	}
 }
 
-func (l *TestLanguageBuilder) Base() string {
+func (l *TestLanguageBuilder) Base(customImage string) string {
 	l.BaseInvoked = true
-	return l.BaseFn()
+	return l.BaseFn(customImage)
 }
 
 func (l *TestLanguageBuilder) WriteShared(job buildJob) ([]imageLayer, error) {

pkg/oci/go_builder.go

@@ -18,8 +18,9 @@ import (
 
 type goBuilder struct{}
 
-func (b goBuilder) Base() string {
-	return "" // scratch
+func (b goBuilder) Base(customImage string) string {
+	// if not defined -> return "", meaning building from scratch
+	return customImage
 }
 
 func (b goBuilder) Configure(_ buildJob, _ v1.Platform, cf v1.ConfigFile) (v1.ConfigFile, error) {

pkg/oci/python_builder.go

@@ -19,7 +19,10 @@ var defaultPythonBase = "python:3.13-slim" // Moving from docker.io.  See issue
 
 type pythonBuilder struct{}
 
-func (b pythonBuilder) Base() string {
+func (b pythonBuilder) Base(customBase string) string {
+	if customBase != "" {
+		return customBase
+	}
 	return defaultPythonBase
 }