feat: add Os and Arch template options to the Binary name field (#1936)

* allow Os and Arch tmpl variables in binary name

* update documentation

* fix docs

internal/pipe/build/build.go

@@ -164,8 +164,22 @@ func doBuild(ctx *context.Context, build config.Build, opts builders.Options) er
 
 func buildOptionsForTarget(ctx *context.Context, build config.Build, target string) (*builders.Options, error) {
 	var ext = extFor(target, build.Flags)
+	var goos string
+	var goarch string
 
-	binary, err := tmpl.New(ctx).Apply(build.Binary)
+	if strings.Contains(target, "_") {
+		goos = strings.Split(target, "_")[0]
+		goarch = strings.Split(target, "_")[1]
+	}
+
+	buildOpts := builders.Options{
+		Target: target,
+		Ext:    ext,
+		Os:     goos,
+		Arch:   goarch,
+	}
+
+	binary, err := tmpl.New(ctx).WithBuildOptions(buildOpts).Apply(build.Binary)
 	if err != nil {
 		return nil, err
 	}
@@ -183,23 +197,10 @@ func buildOptionsForTarget(ctx *context.Context, build config.Build, target stri
 		return nil, err
 	}
 
-	var goos string
-	var goarch string
-
-	if strings.Contains(target, "_") {
-		goos = strings.Split(target, "_")[0]
-		goarch = strings.Split(target, "_")[1]
-	}
-
 	log.WithField("binary", path).Info("building")
-	return &builders.Options{
-		Target: target,
-		Name:   name,
-		Path:   path,
-		Ext:    ext,
-		Os:     goos,
-		Arch:   goarch,
-	}, nil
+	buildOpts.Name = name
+	buildOpts.Path = path
+	return &buildOpts, nil
 }
 
 func extFor(target string, flags config.FlagArray) string {

internal/pipe/build/build_test.go

@@ -706,28 +706,58 @@ func TestPipeOnBuild_invalidBinaryTpl(t *testing.T) {
 func TestBuildOptionsForTarget(t *testing.T) {
 	var tmpDir = testlib.Mktmp(t)
 
-	build := config.Build{
-		ID:     "testid",
-		Binary: "testbinary",
-		Targets: []string{
-			"linux_amd64",
-			"darwin_amd64",
-			"windows_amd64",
+	testCases := []struct {
+		name  string
+		build config.Build
+		expectedOpts *api.Options
+	}{
+		{
+			name: "simple options for target",
+			build: config.Build{
+				ID:     "testid",
+				Binary: "testbinary",
+				Targets: []string{
+					"linux_amd64",
+				},
+			},
+			expectedOpts: &api.Options{
+				Name:   "testbinary",
+				Path:   filepath.Join(tmpDir, "testid_linux_amd64", "testbinary"),
+				Target: "linux_amd64",
+				Os:     "linux",
+				Arch:   "amd64",
+			},
+		},
+		{
+			name: "binary name with Os and Arch template variables",
+			build: config.Build{
+				ID:     "testid",
+				Binary: "testbinary_{{.Os}}_{{.Arch}}",
+				Targets: []string{
+					"linux_amd64",
+				},
+			},
+			expectedOpts: &api.Options{
+				Name:   "testbinary_linux_amd64",
+				Path:   filepath.Join(tmpDir, "testid_linux_amd64", "testbinary_linux_amd64"),
+				Target: "linux_amd64",
+				Os:     "linux",
+				Arch:   "amd64",
+			},
 		},
 	}
-	ctx := context.New(config.Project{
-		Dist:   tmpDir,
-		Builds: []config.Build{build},
-	})
-	opts, err := buildOptionsForTarget(ctx, build, "linux_amd64")
-	require.NoError(t, err)
-	require.Equal(t, &api.Options{
-		Name:   "testbinary",
-		Path:   filepath.Join(tmpDir, "testid_linux_amd64", "testbinary"),
-		Target: "linux_amd64",
-		Os:     "linux",
-		Arch:   "amd64",
-	}, opts)
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := context.New(config.Project{
+				Dist:   tmpDir,
+				Builds: []config.Build{tc.build},
+			})
+			opts, err := buildOptionsForTarget(ctx, tc.build, tc.build.Targets[0])
+			require.NoError(t, err)
+			require.Equal(t, tc.expectedOpts, opts)
+		})
+	}
 }
 
 func TestHookComplex(t *testing.T) {

www/docs/customization/build.md

@@ -159,6 +159,16 @@ builds:
       - windows
 ```
 
+The binary name field supports [templating](/customization/templates/). The following build details are exposed:
+
+| Key     | Description                      |
+|---------|----------------------------------|
+| .Os     | `GOOS`                           |
+| .Arch   | `GOARCH`                         |
+| .Arm    | `GOARM`                          |
+| .Ext    | Extension, e.g. `.exe`           |
+| .Target | Build target, e.g. `darwin_amd64`|
+
 ## Passing environment variables to ldflags
 
 You can do that by using `{{ .Env.VARIABLE_NAME }}` in the template, for