container image tag patterns

Author: joonas-fi

cmd/bob/bobfile.go

@@ -144,12 +144,38 @@ type DevShellCommand struct {
 	Important bool   `json:"important"` // important commands are shown as pro-tips on "$ bob dev"
 }
 
+type Condition struct {
+	IsDefaultBranch *bool `json:"is_default_branch"`
+}
+
+func (c *Condition) Passes(buildCtx *BuildContext) bool {
+	if c == nil { // no conditions
+		return true
+	}
+
+	hasFilter := func(b *bool) bool { return b != nil }
+
+	if hasFilter(c.IsDefaultBranch) {
+		if *c.IsDefaultBranch != buildCtx.IsDefaultBranch {
+			return false
+		}
+	}
+
+	return true
+}
+
+type TagSpec struct {
+	Pattern string     `json:"pattern"`
+	UseIf   *Condition `json:"use_if"`
+}
+
 type DockerImageSpec struct {
-	Image          string   `json:"image"`
-	DockerfilePath string   `json:"dockerfile_path"`
-	AuthType       *string  `json:"auth_type"`           // creds_from_env
-	Platforms      []string `json:"platforms,omitempty"` // if set, uses buildx
-	TagLatest      bool     `json:"tag_latest"`
+	Image          string    `json:"image"`
+	DockerfilePath string    `json:"dockerfile_path"`
+	AuthType       *string   `json:"auth_type"`           // creds_from_env
+	Platforms      []string  `json:"platforms,omitempty"` // if set, uses buildx
+	Tags           []TagSpec `json:"tags"`
+	TagLatest      bool      `json:"tag_latest"` // deprecated
 }
 
 // FIXME: Bobfile should actually be read only after correct

cmd/bob/build.go

@@ -126,14 +126,14 @@ func runBuilder(builder BuilderSpec, buildCtx *BuildContext, opDesc string, cmdT
 }
 
 func buildAndPushOneDockerImage(dockerImage DockerImageSpec, buildCtx *BuildContext) error {
-	tagWithoutVersion := dockerImage.Image
-	tag := tagWithoutVersion + ":" + buildCtx.RevisionId.FriendlyRevisionId
-	tagLatest := tagWithoutVersion + ":latest"
-	dockerfilePath := dockerImage.DockerfilePath
-
-	// only tag latest from the default branch (= main / master / ...), because it is expected
-	// that non-default branch builds are dev/experimental builds.
-	shouldTagLatest := dockerImage.TagLatest && buildCtx.IsDefaultBranch
+	tagSpecs := func() []TagSpec {
+		if len(dockerImage.Tags) > 0 {
+			return dockerImage.Tags
+		} else {
+			return createBackwardsCompatTagSpecs(dockerImage.TagLatest)
+		}
+	}()
+	tags := expandTagSpecs(tagSpecs, buildCtx, dockerImage.Image)
 
 	labelArgs := []string{
 		"--label=org.opencontainers.image.created=" + time.Now().UTC().Format(time.RFC3339),
@@ -151,9 +151,9 @@ func buildAndPushOneDockerImage(dockerImage DockerImageSpec, buildCtx *BuildCont
 	// "" => "."
 	// "Dockerfile" => "."
 	// "subdir/Dockerfile" => "subdir"
-	buildContextDir := filepath.Dir(dockerfilePath)
+	buildContextDir := filepath.Dir(dockerImage.DockerfilePath)
 
-	printHeading(fmt.Sprintf("Building %s", tag))
+	printHeading(fmt.Sprintf("Building %s", dockerImage.Image))
 
 	// use buildx when platforms set. it's almost same as "$ docker build" but it almost transparently
 	// supports cross-architecture builds via binftm_misc + QEMU userspace emulation
@@ -166,16 +166,11 @@ func buildAndPushOneDockerImage(dockerImage DockerImageSpec, buildCtx *BuildCont
 			"buildx",
 			"build",
 			"--platform", strings.Join(dockerImage.Platforms, ","),
-			"--file", dockerfilePath,
-			"--tag=" + tag,
+			"--file", dockerImage.DockerfilePath,
 		}
 
+		args = append(args, dockerTagArgs(tags)...)
 		args = append(args, labelArgs...)
-
-		if shouldTagLatest {
-			args = append(args, "--tag="+tagLatest)
-		}
-
 		args = append(args, buildContextDir)
 
 		if buildCtx.PublishArtefacts {
@@ -190,8 +185,8 @@ func buildAndPushOneDockerImage(dockerImage DockerImageSpec, buildCtx *BuildCont
 
 	dockerBuildArgs := []string{"docker",
 		"build",
-		"--file", dockerfilePath,
-		"--tag", tag}
+		"--file", dockerImage.DockerfilePath}
+	dockerBuildArgs = append(dockerBuildArgs, dockerTagArgs(tags)...)
 	dockerBuildArgs = append(dockerBuildArgs, labelArgs...)
 	dockerBuildArgs = append(dockerBuildArgs, buildContextDir)
 
@@ -218,21 +213,11 @@ func buildAndPushOneDockerImage(dockerImage DockerImageSpec, buildCtx *BuildCont
 			return nil
 		}
 
-		if err := pushTag(tag); err != nil {
-			return err
-		}
-
-		if shouldTagLatest {
-			if err := exec.Command("docker", "tag", tag, tagLatest).Run(); err != nil {
-				return fmt.Errorf("tagging failed %s -> %s failed: %v", tag, tagLatest, err)
-			}
-
-			if err := pushTag(tagLatest); err != nil {
+		for _, tag := range tags {
+			if err := pushTag(tag); err != nil {
 				return err
 			}
 		}
-
-		return nil
 	}
 
 	return nil

cmd/bob/docker.go

@@ -111,6 +111,14 @@ func buildBuilder(bobfile *Bobfile, builder *BuilderSpec) error {
 	return nil
 }
 
+func dockerTagArgs(tags []string) []string {
+	asArgs := []string{}
+	for _, tag := range tags {
+		asArgs = append(asArgs, fmt.Sprintf("--tag=%s", tag))
+	}
+	return asArgs
+}
+
 func dockerRelayEnvVars(
 	dockerArgs []string,
 	revisionId *versioncontrol.RevisionId,

cmd/bob/tags.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func expandTagSpecs(specs []TagSpec, buildCtx *BuildContext, imagePrefix string) []string {
+	createTag := func(tag string) string { return fmt.Sprintf("%s:%s", imagePrefix, tag) }
+
+	tags := []string{}
+
+	for _, spec := range specs {
+		if !spec.UseIf.Passes(buildCtx) {
+			continue
+		}
+
+		placeholdersReplaced := strings.ReplaceAll(spec.Pattern, "{rev_short}", buildCtx.RevisionId.RevisionIdShort)
+		placeholdersReplaced = strings.ReplaceAll(placeholdersReplaced, "{rev_friendly}", buildCtx.RevisionId.FriendlyRevisionId)
+
+		tags = append(tags, createTag(placeholdersReplaced))
+	}
+
+	return tags
+}
+
+// backwards compat: model old behaviour on top of newer `TagSpec` facility:
+//
+// 1. `{rev_friendly}` tag gets always pushed
+// 2. `latest` gets pushed if `tag_latest=true` and if we're in default branch
+func createBackwardsCompatTagSpecs(maybeTagLatest bool) []TagSpec {
+	tags := []TagSpec{
+		{
+			Pattern: "{rev_friendly}",
+		},
+	}
+
+	if maybeTagLatest {
+		true_ := true
+
+		tags = append(tags, TagSpec{
+			Pattern: "latest",
+			UseIf: &Condition{
+				IsDefaultBranch: &true_,
+			},
+		})
+	}
+
+	return tags
+}

cmd/bob/tags_test.go

@@ -0,0 +1,72 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/function61/gokit/testing/assert"
+	"github.com/function61/turbobob/pkg/versioncontrol"
+)
+
+func TestExpandTagSpecs(t *testing.T) {
+	true_ := true
+
+	exampleRevision := &versioncontrol.RevisionId{
+		RevisionId:         "df9e1a0b32d41977b49742d57702fbae0392c49a",
+		RevisionIdShort:    "df9e1a0b",
+		FriendlyRevisionId: "20240616_0924_df9e1a0b",
+	}
+
+	defaultBuildContext := &BuildContext{RevisionId: exampleRevision}
+
+	for _, tc := range []struct {
+		input        TagSpec
+		buildContext *BuildContext
+		output       string
+	}{
+		{
+			input: TagSpec{
+				Pattern: "latest",
+			},
+			buildContext: &BuildContext{
+				RevisionId:      exampleRevision,
+				IsDefaultBranch: true,
+			},
+			output: "[joonas:latest]",
+		},
+		{
+			input: TagSpec{
+				Pattern: "latest",
+				UseIf: &Condition{
+					IsDefaultBranch: &true_,
+				},
+			},
+			buildContext: &BuildContext{
+				RevisionId:      exampleRevision,
+				IsDefaultBranch: false,
+			},
+			output: "[]",
+		},
+		{
+			input: TagSpec{
+				Pattern: "sha-{rev_short}",
+			},
+			buildContext: defaultBuildContext,
+			output:       "[joonas:sha-df9e1a0b]",
+		},
+		{
+			input: TagSpec{
+				Pattern: "{rev_friendly}",
+			},
+			buildContext: defaultBuildContext,
+			output:       "[joonas:20240616_0924_df9e1a0b]",
+		},
+	} {
+		tc := tc // pin
+
+		t.Run(tc.output, func(t *testing.T) {
+			tags := expandTagSpecs([]TagSpec{tc.input}, tc.buildContext, "joonas")
+			assert.Equal(t, fmt.Sprintf("%v", tags), tc.output)
+		})
+	}
+}