bake: allow BAKE_CMD_CONTEXT builtin var

Allows accessing the main context for bake command from bake
file that has been imported remotely.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

bake/bake.go

@@ -61,8 +61,8 @@ func ReadLocalFiles(names []string) ([]File, error) {
 	return out, nil
 }
 
-func ReadTargets(ctx context.Context, files []File, targets, overrides []string) (map[string]*Target, error) {
+func ReadTargets(ctx context.Context, files []File, targets, overrides []string, defaults map[string]string) (map[string]*Target, error) {
-	c, err := ParseFiles(files)
+	c, err := ParseFiles(files, defaults)
 	if err != nil {
 		return nil, err
 	}
@@ -86,7 +86,7 @@ func ReadTargets(ctx context.Context, files []File, targets, overrides []string)
 	return m, nil
 }
 
-func ParseFiles(files []File) (_ *Config, err error) {
+func ParseFiles(files []File, defaults map[string]string) (_ *Config, err error) {
 	defer func() {
 		err = formatHCLError(err, files)
 	}()
@@ -120,6 +120,7 @@ func ParseFiles(files []File) (_ *Config, err error) {
 	if len(fs) > 0 {
 		if err := hclparser.Parse(hcl.MergeFiles(fs), hclparser.Opt{
 			LookupVar: os.LookupEnv,
+			Vars:      defaults,
 		}, &c); err.HasErrors() {
 			return nil, err
 		}
@@ -143,7 +144,7 @@ func dedupeConfig(c Config) Config {
 }
 
 func ParseFile(dt []byte, fn string) (*Config, error) {
-	return ParseFiles([]File{{Data: dt, Name: fn}})
+	return ParseFiles([]File{{Data: dt, Name: fn}}, nil)
 }
 
 func ParseComposeFile(dt []byte, fn string) (*Config, bool, error) {
@@ -526,6 +527,12 @@ func updateContext(t *build.Inputs, inp *Input) {
 		t.ContextPath = inp.URL
 		return
 	}
+	if strings.HasPrefix(t.ContextPath, "cwd://") {
+		return
+	}
+	if IsRemoteURL(t.ContextPath) {
+		return
+	}
 	st := llb.Scratch().File(llb.Copy(*inp.State, t.ContextPath, "/"), llb.WithCustomNamef("set context to %s", t.ContextPath))
 	t.ContextState = &st
 }
@@ -542,7 +549,9 @@ func toBuildOpt(t *Target, inp *Input) (*build.Options, error) {
 	if t.Context != nil {
 		contextPath = *t.Context
 	}
-	contextPath = path.Clean(contextPath)
+	if !strings.HasPrefix(contextPath, "cwd://") && !IsRemoteURL(contextPath) {
+		contextPath = path.Clean(contextPath)
+	}
 	dockerfilePath := "Dockerfile"
 	if t.Dockerfile != nil {
 		dockerfilePath = *t.Dockerfile
@@ -569,6 +578,11 @@ func toBuildOpt(t *Target, inp *Input) (*build.Options, error) {
 		bi.DockerfileInline = *t.DockerfileInline
 	}
 	updateContext(&bi, inp)
+	if strings.HasPrefix(bi.ContextPath, "cwd://") {
+		bi.ContextPath = path.Clean(strings.TrimPrefix(bi.ContextPath, "cwd://"))
+	}
+
+	t.Context = &bi.ContextPath
 
 	bo := &build.Options{
 		Inputs:    bi,

bake/bake_test.go

@@ -34,7 +34,7 @@ target "webapp" {
 	ctx := context.TODO()
 
 	t.Run("NoOverrides", func(t *testing.T) {
-		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, nil)
+		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, nil, nil)
 		require.NoError(t, err)
 		require.Equal(t, 1, len(m))
 
@@ -46,7 +46,7 @@ target "webapp" {
 	})
 
 	t.Run("InvalidTargetOverrides", func(t *testing.T) {
-		_, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"nosuchtarget.context=foo"})
+		_, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"nosuchtarget.context=foo"}, nil)
 		require.NotNil(t, err)
 		require.Equal(t, err.Error(), "could not find any target matching 'nosuchtarget'")
 	})
@@ -63,7 +63,7 @@ target "webapp" {
 				"webapp.args.VAR_FROMENV" + t.Name(),
 				"webapp.args.VAR_INHERITED=override",
 				// not overriding VAR_BOTH on purpose
-			})
+			}, nil)
 			require.NoError(t, err)
 
 			require.Equal(t, "Dockerfile.webapp", *m["webapp"].Dockerfile)
@@ -88,7 +88,7 @@ target "webapp" {
 			m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{
 				"webDEP.args.VAR_INHERITED=override",
 				"webDEP.args.VAR_BOTH=override",
-			})
+			}, nil)
 			require.NoError(t, err)
 			require.Equal(t, m["webapp"].Args["VAR_INHERITED"], "override")
 			require.Equal(t, m["webapp"].Args["VAR_BOTH"], "webapp")
@@ -96,23 +96,23 @@ target "webapp" {
 	})
 
 	t.Run("ContextOverride", func(t *testing.T) {
-		_, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.context"})
+		_, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.context"}, nil)
 		require.NotNil(t, err)
 
-		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.context=foo"})
+		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.context=foo"}, nil)
 		require.NoError(t, err)
 
 		require.Equal(t, "foo", *m["webapp"].Context)
 	})
 
 	t.Run("NoCacheOverride", func(t *testing.T) {
-		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.no-cache=false"})
+		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.no-cache=false"}, nil)
 		require.NoError(t, err)
 		require.Equal(t, false, *m["webapp"].NoCache)
 	})
 
 	t.Run("PullOverride", func(t *testing.T) {
-		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.pull=false"})
+		m, err := ReadTargets(ctx, []File{fp}, []string{"webapp"}, []string{"webapp.pull=false"}, nil)
 		require.NoError(t, err)
 		require.Equal(t, false, *m["webapp"].Pull)
 	})
@@ -172,7 +172,7 @@ target "webapp" {
 		}
 		for _, test := range cases {
 			t.Run(test.name, func(t *testing.T) {
-				m, err := ReadTargets(ctx, []File{fp}, test.targets, test.overrides)
+				m, err := ReadTargets(ctx, []File{fp}, test.targets, test.overrides, nil)
 				test.check(t, m, err)
 			})
 		}
@@ -215,7 +215,7 @@ services:
 
 	ctx := context.TODO()
 
-	m, err := ReadTargets(ctx, []File{fp, fp2}, []string{"default"}, nil)
+	m, err := ReadTargets(ctx, []File{fp, fp2}, []string{"default"}, nil, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 3, len(m))
@@ -226,3 +226,28 @@ services:
 	require.Equal(t, "1", m["webapp"].Args["buildno"])
 	require.Equal(t, "12", m["webapp"].Args["buildno2"])
 }
+
+func TestHCLCwdPrefix(t *testing.T) {
+
+	fp := File{
+		Name: "docker-bake.hc",
+		Data: []byte(
+			`target "app" {
+				context = "cwd://foo"
+				dockerfile = "test"
+			}`),
+	}
+	ctx := context.TODO()
+	m, err := ReadTargets(ctx, []File{fp}, []string{"app"}, nil, nil)
+	require.NoError(t, err)
+
+	require.Equal(t, 1, len(m))
+	_, ok := m["app"]
+	require.True(t, ok)
+
+	_, err = TargetsToBuildOpt(m, &Input{})
+	require.NoError(t, err)
+
+	require.Equal(t, "test", *m["app"].Dockerfile)
+	require.Equal(t, "foo", *m["app"].Context)
+}

bake/hcl_test.go

@@ -276,7 +276,7 @@ func TestHCLMultiFileSharedVariables(t *testing.T) {
 	c, err := ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.hcl"},
-	})
+	}, nil)
 	require.NoError(t, err)
 	require.Equal(t, 1, len(c.Targets))
 	require.Equal(t, c.Targets[0].Name, "app")
@@ -288,7 +288,7 @@ func TestHCLMultiFileSharedVariables(t *testing.T) {
 	c, err = ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.hcl"},
-	})
+	}, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 1, len(c.Targets))
@@ -326,7 +326,7 @@ func TestHCLVarsWithVars(t *testing.T) {
 	c, err := ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.hcl"},
-	})
+	}, nil)
 	require.NoError(t, err)
 	require.Equal(t, 1, len(c.Targets))
 	require.Equal(t, c.Targets[0].Name, "app")
@@ -338,7 +338,7 @@ func TestHCLVarsWithVars(t *testing.T) {
 	c, err = ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.hcl"},
-	})
+	}, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 1, len(c.Targets))
@@ -483,7 +483,7 @@ func TestHCLMultiFileAttrs(t *testing.T) {
 	c, err := ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.hcl"},
-	})
+	}, nil)
 	require.NoError(t, err)
 	require.Equal(t, 1, len(c.Targets))
 	require.Equal(t, c.Targets[0].Name, "app")
@@ -494,7 +494,7 @@ func TestHCLMultiFileAttrs(t *testing.T) {
 	c, err = ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.hcl"},
-	})
+	}, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 1, len(c.Targets))
@@ -589,7 +589,7 @@ services:
 	c, err := ParseFiles([]File{
 		{Data: dt, Name: "c1.hcl"},
 		{Data: dt2, Name: "c2.yml"},
-	})
+	}, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 1, len(c.Targets))
@@ -599,3 +599,24 @@ services:
 	require.Equal(t, "dir", *c.Targets[0].Context)
 	require.Equal(t, "Dockerfile-alternate", *c.Targets[0].Dockerfile)
 }
+
+func TestHCLBuiltinVars(t *testing.T) {
+	dt := []byte(`
+		target "app" {
+			context = BAKE_CMD_CONTEXT
+			dockerfile = "test"
+		}
+		`)
+
+	c, err := ParseFiles([]File{
+		{Data: dt, Name: "c1.hcl"},
+	}, map[string]string{
+		"BAKE_CMD_CONTEXT": "foo",
+	})
+	require.NoError(t, err)
+
+	require.Equal(t, 1, len(c.Targets))
+	require.Equal(t, c.Targets[0].Name, "app")
+	require.Equal(t, "foo", *c.Targets[0].Context)
+	require.Equal(t, "test", *c.Targets[0].Dockerfile)
+}

bake/hclparser/hclparser.go

@@ -17,6 +17,7 @@ import (
 
 type Opt struct {
 	LookupVar func(string) (string, bool)
+	Vars      map[string]string
 }
 
 type variable struct {
@@ -178,7 +179,7 @@ func (p *parser) resolveValue(name string) (err error) {
 	}()
 
 	def, ok := p.attrs[name]
-	if !ok {
+	if _, builtin := p.opt.Vars[name]; !ok && !builtin {
 		vr, ok := p.vars[name]
 		if !ok {
 			return errors.Errorf("undefined variable %q", name)
@@ -187,7 +188,10 @@ func (p *parser) resolveValue(name string) (err error) {
 	}
 
 	if def == nil {
-		val, _ := p.opt.LookupVar(name)
+		val, ok := p.opt.Vars[name]
+		if !ok {
+			val, _ = p.opt.LookupVar(name)
+		}
 		vv := cty.StringVal(val)
 		v = &vv
 		return
@@ -243,6 +247,9 @@ func Parse(b hcl.Body, opt Opt, val interface{}) hcl.Diagnostics {
 	for _, bs := range schema.Blocks {
 		reserved[bs.Type] = struct{}{}
 	}
+	for k := range opt.Vars {
+		reserved[k] = struct{}{}
+	}
 
 	var defs inputs
 	if err := gohcl.DecodeBody(b, nil, &defs); err != nil {
@@ -303,6 +310,10 @@ func Parse(b hcl.Body, opt Opt, val interface{}) hcl.Diagnostics {
 	}
 	delete(p.attrs, "function")
 
+	for k := range p.opt.Vars {
+		_ = p.resolveValue(k)
+	}
+
 	for k := range p.attrs {
 		if err := p.resolveValue(k); err != nil {
 			if diags, ok := err.(hcl.Diagnostics); ok {

commands/bake.go

@@ -36,11 +36,19 @@ func runBake(dockerCli command.Cli, targets []string, in bakeOptions) (err error
 	}()
 
 	var url string
+	cmdContext := "cwd://"
 
 	if len(targets) > 0 {
 		if bake.IsRemoteURL(targets[0]) {
 			url = targets[0]
 			targets = targets[1:]
+			if len(targets) > 0 {
+				if bake.IsRemoteURL(targets[0]) {
+					cmdContext = targets[0]
+					targets = targets[1:]
+
+				}
+			}
 		}
 	}
 
@@ -85,6 +93,7 @@ func runBake(dockerCli command.Cli, targets []string, in bakeOptions) (err error
 
 	var files []bake.File
 	var inp *bake.Input
+
 	if url != "" {
 		files, inp, err = bake.ReadRemoteFiles(ctx, dis, url, in.files, printer)
 	} else {
@@ -94,7 +103,15 @@ func runBake(dockerCli command.Cli, targets []string, in bakeOptions) (err error
 		return err
 	}
 
-	m, err := bake.ReadTargets(ctx, files, targets, overrides)
+	m, err := bake.ReadTargets(ctx, files, targets, overrides, map[string]string{
+		"BAKE_CMD_CONTEXT": cmdContext,
+	})
+	if err != nil {
+		return err
+	}
+
+	// this function can update target context string from the input so call before printOnly check
+	bo, err := bake.TargetsToBuildOpt(m, inp)
 	if err != nil {
 		return err
 	}
@@ -113,11 +130,6 @@ func runBake(dockerCli command.Cli, targets []string, in bakeOptions) (err error
 		return nil
 	}
 
-	bo, err := bake.TargetsToBuildOpt(m, inp)
-	if err != nil {
-		return err
-	}
-
 	resp, err := build.Build(ctx, dis, bo, dockerAPI(dockerCli), dockerCli.ConfigFile(), printer)
 	if err != nil {
 		return err