feat(ko): snapshot builds (#5116)

this makes ko run on snapshot builds, too.

the image will be `goreleaser.ko.local:[your tags]`, not sure if we can
change this, seems like we can't.

also fixed a small doc error around it, as well as added a new test to
cover this.

closes #4683

---------

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

internal/pipe/ko/ko.go

@@ -138,6 +138,15 @@ func (Pipe) Default(ctx *context.Context) error {
 	return ids.Validate()
 }
 
+func (p Pipe) Run(ctx *context.Context) error {
+	if ctx.Snapshot {
+		// publish actually handles pushing to the local docker daemon when
+		// snapshot is true.
+		return p.Publish(ctx)
+	}
+	return nil
+}
+
 // Publish executes the Pipe.
 func (Pipe) Publish(ctx *context.Context) error {
 	g := semerrgroup.New(ctx.Parallelism)
@@ -249,17 +258,32 @@ func doBuild(ctx *context.Context, ko config.Ko) func() error {
 			return fmt.Errorf("build: %w", err)
 		}
 
-		po := []publish.Option{publish.WithTags(opts.tags), publish.WithNamer(options.MakeNamer(&options.PublishOptions{
+		po := &options.PublishOptions{
 			DockerRepo:          opts.imageRepo,
 			Bare:                opts.bare,
 			PreserveImportPaths: opts.preserveImportPaths,
 			BaseImportPaths:     opts.baseImportPaths,
 			Tags:                opts.tags,
-		})), publish.WithAuthFromKeychain(keychain)}
-
-		p, err := publish.NewDefault(opts.imageRepo, po...)
+			Local:               ctx.Snapshot,
+			LocalDomain:         "goreleaser.ko.local",
+		}
+		var p publish.Interface
+		if ctx.Snapshot {
+			p, err = publish.NewDaemon(
+				options.MakeNamer(po),
+				opts.tags,
+				publish.WithLocalDomain(po.LocalDomain),
+			)
+		} else {
+			p, err = publish.NewDefault(
+				opts.imageRepo,
+				publish.WithTags(opts.tags),
+				publish.WithNamer(options.MakeNamer(po)),
+				publish.WithAuthFromKeychain(keychain),
+			)
+		}
 		if err != nil {
-			return fmt.Errorf("newDefault: %w", err)
+			return fmt.Errorf("newPublisher: %w", err)
 		}
 		defer func() { _ = p.Close() }()
 		ref, err := p.Publish(ctx, r, opts.importPath)

internal/pipe/ko/ko_test.go

@@ -377,6 +377,41 @@ func TestPublishPipeSuccess(t *testing.T) {
 	}
 }
 
+func TestSnapshot(t *testing.T) {
+	ctx := testctx.NewWithCfg(config.Project{
+		ProjectName: "test",
+		Builds: []config.Build{
+			{
+				ID: "foo",
+				BuildDetails: config.BuildDetails{
+					Ldflags: []string{"-s", "-w"},
+					Flags:   []string{"-tags", "netgo"},
+					Env:     []string{"GOCACHE=" + t.TempDir()},
+				},
+			},
+		},
+		Kos: []config.Ko{
+			{
+				ID:         "default",
+				Build:      "foo",
+				Repository: "testimage",
+				WorkingDir: "./testdata/app/",
+				Tags:       []string{"latest"},
+			},
+		},
+	}, testctx.WithVersion("1.2.0"), testctx.Snapshot)
+
+	require.NoError(t, Pipe{}.Default(ctx))
+	require.NoError(t, Pipe{}.Run(ctx))
+
+	manifests := ctx.Artifacts.Filter(artifact.ByType(artifact.DockerManifest)).List()
+	require.Len(t, manifests, 1)
+	require.NotEmpty(t, manifests[0].Name)
+	require.Equal(t, manifests[0].Name, manifests[0].Path)
+	require.NotEmpty(t, manifests[0].Extra[artifact.ExtraDigest])
+	require.Equal(t, "default", manifests[0].Extra[artifact.ExtraID])
+}
+
 func TestKoValidateMainPathIssue4382(t *testing.T) {
 	// testing the validation of the main path directly to cover many cases
 	require.NoError(t, validateMainPath(""))

internal/pipeline/pipeline.go

@@ -20,6 +20,7 @@ import (
 	"github.com/goreleaser/goreleaser/v2/internal/pipe/env"
 	"github.com/goreleaser/goreleaser/v2/internal/pipe/git"
 	"github.com/goreleaser/goreleaser/v2/internal/pipe/gomod"
+	"github.com/goreleaser/goreleaser/v2/internal/pipe/ko"
 	"github.com/goreleaser/goreleaser/v2/internal/pipe/krew"
 	"github.com/goreleaser/goreleaser/v2/internal/pipe/metadata"
 	"github.com/goreleaser/goreleaser/v2/internal/pipe/nfpm"
@@ -146,6 +147,8 @@ var Pipeline = append(
 	reportsizes.Pipe{},
 	// create and push docker images
 	docker.Pipe{},
+	// create and push docker images using ko
+	ko.Pipe{},
 	// publishes artifacts
 	publish.New(),
 	// creates a artifacts.json files in the dist directory

www/docs/customization/ko.md

@@ -133,7 +133,7 @@ builds:
       - linux
     goarch:
       - amd64
-      - arch64
+      - arm64
 
 kos:
   - repository: ghcr.io/caarlos0/test-ko