feat(build): allow to template env (#3592)

GoReleaser evolved a lot since the last time I tried to implement this
>1 year ago.
Now its 100% possible, and way simpler to do it!

closes #3580
refs #2583

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

internal/builders/golang/build.go

@@ -165,7 +165,23 @@ func (*Builder) Build(ctx *context.Context, build config.Build, options api.Opti
 		return err
 	}
 
-	env := append(ctx.Env.Strings(), details.Env...)
+	env := []string{}
+	// used for unit testing only
+	testEnvs := []string{}
+	env = append(env, ctx.Env.Strings()...)
+	for _, e := range details.Env {
+		ee, err := tmpl.New(ctx).WithEnvS(env).WithArtifact(a, nil).Apply(e)
+		if err != nil {
+			return err
+		}
+		log.Debugf("env %q evaluated to %q", e, ee)
+		if ee != "" {
+			env = append(env, ee)
+			if strings.HasPrefix(e, "TEST_") {
+				testEnvs = append(testEnvs, ee)
+			}
+		}
+	}
 	env = append(
 		env,
 		"GOOS="+options.Goos,
@@ -176,6 +192,10 @@ func (*Builder) Build(ctx *context.Context, build config.Build, options api.Opti
 		"GOAMD64="+options.Goamd64,
 	)
 
+	if len(testEnvs) > 0 {
+		a.Extra["testEnvs"] = testEnvs
+	}
+
 	cmd, err := buildGoBuildLine(ctx, build, details, options, a, env)
 	if err != nil {
 		return err

internal/builders/golang/build_test.go

@@ -363,7 +363,16 @@ func TestBuild(t *testing.T) {
 				GoBinary: "go",
 				Command:  "build",
 				BuildDetails: config.BuildDetails{
-					Env:      []string{"GO111MODULE=off"},
+					Env: []string{
+						"GO111MODULE=off",
+						`TEST_T={{- if eq .Os "windows" -}}
+						w
+						{{- else if eq .Os "darwin" -}}
+						d
+						{{- else if eq .Os "linux" -}}
+						l
+						{{- end -}}`,
+					},
 					Asmflags: []string{".=", "all="},
 					Gcflags:  []string{"all="},
 					Flags:    []string{"{{.Env.GO_FLAGS}}"},
@@ -426,6 +435,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    "",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T=l"},
 			},
 		},
 		{
@@ -439,6 +449,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    "",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T=l"},
 			},
 		},
 		{
@@ -452,6 +463,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    "",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T=l"},
 			},
 		},
 		{
@@ -464,6 +476,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    "",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T=d"},
 			},
 		},
 		{
@@ -477,6 +490,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    "",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T=l"},
 			},
 		},
 		{
@@ -489,6 +503,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    ".exe",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T=w"},
 			},
 		},
 		{
@@ -501,6 +516,7 @@ func TestBuild(t *testing.T) {
 				artifact.ExtraExt:    ".wasm",
 				artifact.ExtraBinary: "foo-v5.6.7",
 				artifact.ExtraID:     "foo",
+				"testEnvs":           []string{"TEST_T="},
 			},
 		},
 	})
@@ -524,6 +540,37 @@ func TestBuild(t *testing.T) {
 	}
 }
 
+func TestBuildInvalidEnv(t *testing.T) {
+	folder := testlib.Mktmp(t)
+	writeGoodMain(t, folder)
+	config := config.Project{
+		Builds: []config.Build{
+			{
+				ID:     "foo",
+				Dir:    ".",
+				Binary: "foo",
+				Targets: []string{
+					runtimeTarget,
+				},
+				GoBinary: "go",
+				BuildDetails: config.BuildDetails{
+					Env: []string{"GO111MODULE={{ .Nope }}"},
+				},
+			},
+		},
+	}
+	ctx := context.New(config)
+	ctx.Git.CurrentTag = "5.6.7"
+	build := ctx.Config.Builds[0]
+	err := Default.Build(ctx, build, api.Options{
+		Target: runtimeTarget,
+		Name:   build.Binary,
+		Path:   filepath.Join(folder, "dist", runtimeTarget, build.Binary),
+		Ext:    "",
+	})
+	testlib.RequireTemplateError(t, err)
+}
+
 func TestBuildCodeInSubdir(t *testing.T) {
 	folder := testlib.Mktmp(t)
 	subdir := filepath.Join(folder, "bar")

internal/pipe/build/build.go

@@ -115,9 +115,7 @@ func runHook(ctx *context.Context, opts builders.Options, buildEnv []string, hoo
 		var env []string
 
 		env = append(env, ctx.Env.Strings()...)
-		env = append(env, buildEnv...)
-
-		for _, rawEnv := range hook.Env {
+		for _, rawEnv := range append(buildEnv, hook.Env...) {
 			e, err := tmpl.New(ctx).WithBuildOptions(opts).Apply(rawEnv)
 			if err != nil {
 				return err

internal/pipe/build/build_test.go

@@ -121,6 +121,8 @@ func TestRunFullPipe(t *testing.T) {
 	folder := testlib.Mktmp(t)
 	pre := filepath.Join(folder, "pre")
 	post := filepath.Join(folder, "post")
+	preOS := filepath.Join(folder, "pre_linux")
+	postOS := filepath.Join(folder, "post_linux")
 	config := config.Project{
 		Builds: []config.Build{
 			{
@@ -130,13 +132,16 @@ func TestRunFullPipe(t *testing.T) {
 				BuildDetails: config.BuildDetails{
 					Flags:   []string{"-v"},
 					Ldflags: []string{"-X main.test=testing"},
+					Env:     []string{"THE_OS={{ .Os }}"},
 				},
 				Hooks: config.BuildHookConfig{
 					Pre: []config.Hook{
 						{Cmd: "touch " + pre},
+						{Cmd: "touch pre_{{ .Env.THE_OS}}"},
 					},
 					Post: []config.Hook{
 						{Cmd: "touch " + post},
+						{Cmd: "touch post_{{ .Env.THE_OS}}"},
 					},
 				},
 				Targets: []string{"linux_amd64"},
@@ -153,6 +158,8 @@ func TestRunFullPipe(t *testing.T) {
 	}})
 	require.FileExists(t, post)
 	require.FileExists(t, pre)
+	require.FileExists(t, postOS)
+	require.FileExists(t, preOS)
 	require.FileExists(t, filepath.Join(folder, "build1_linux_amd64", "testing"))
 }
 

www/docs/customization/build.md

@@ -71,11 +71,22 @@ builds:
 
     # Custom environment variables to be set during the builds.
     #
+    # This field is templateable. Since v1.14.
+    #
     # Invalid environment variables will be ignored.
     #
     # Default: `os.Environ()` merged with what you set the root `env` section.
     env:
       - CGO_ENABLED=0
+      # complex, templated envs (v1.14+):
+      - >-
+        {{- if eq .Os "darwin" }}
+          {{- if eq .Arch "amd64"}}CC=o64-clang{{- end }}
+          {{- if eq .Arch "arm64"}}CC=aarch64-apple-darwin20.2-clang{{- end }}
+        {{- end }}
+        {{- if eq .Os "windows" }}
+          {{- if eq .Arch "amd64" }}CC=x86_64-w64-mingw32-gcc{{- end }}
+        {{- end }}
 
     # GOOS list to build for.
     # For more info refer to: https://golang.org/doc/install/source#environment
@@ -558,3 +569,83 @@ builds:
     # Configure the buildmode flag to output a shared library
     buildmode: "c-shared"  # or "c-archive" for a static library
 ```
+
+## Complex templated environment variables
+
+> Since v1.14.
+
+Builds environment variables are templateable.
+
+You can leverage that to have a single build configuration with different
+environment variables for each platform, for example.
+
+A common example of this is the variables `CC` and `CCX`.
+
+Here are two different examples:
+
+### Using multiple envs
+
+This example creates once `CC_` and `CCX_` variable for each platform, and then
+set `CC` and `CCX` to the right one:
+
+```yaml
+# .goreleaser.yml
+builds:
+- id: mybin
+  binary: mybin
+  main: .
+  goos:
+    - linux
+    - darwin
+    - windows
+  goarch:
+    - amd64
+    - arm64
+  env:
+    - CGO_ENABLED=0
+    - CC_darwin_amd64=o64-clang
+    - CCX_darwin_amd64=o64-clang+
+    - CC_darwin_arm64=aarch64-apple-darwin20.2-clang
+    - CCX_darwin_arm64=aarch64-apple-darwin20.2-clang++
+    - CC_windows_amd64=x86_64-w64-mingw32-gc
+    - CCX_windows_amd64=x86_64-w64-mingw32-g++
+    - 'CC={{ index .Env (print "CC_" .Os "_" .Arch) }}'
+    - 'CCX={{ index .Env (print "CCX_" .Os "_" .Arch) }}'
+```
+
+### Using `if` statements
+
+This example uses `if` statements to set `CC` and `CCX`:
+
+```yaml
+# .goreleaser.yml
+builds:
+- id: mybin
+  binary: mybin
+  main: .
+  goos:
+    - linux
+    - darwin
+    - windows
+  goarch:
+    - amd64
+    - arm64
+  env:
+    - CGO_ENABLED=0
+    - >-
+        {{- if eq .Os "darwin" }}
+          {{- if eq .Arch "amd64"}}CC=o64-clang{{- end }}
+          {{- if eq .Arch "arm64"}}CC=aarch64-apple-darwin20.2-clang{{- end }}
+        {{- end }}
+        {{- if eq .Os "windows" }}
+          {{- if eq .Arch "amd64" }}CC=x86_64-w64-mingw32-gcc{{- end }}
+        {{- end }}
+    - >-
+        {{- if eq .Os "darwin" }}
+          {{- if eq .Arch "amd64"}}CXX=o64-clang+{{- end }}
+          {{- if eq .Arch "arm64"}}CXX=aarch64-apple-darwin20.2-clang++{{- end }}
+        {{- end }}
+        {{- if eq .Os "windows" }}
+          {{- if eq .Arch "amd64" }}CXX=x86_64-w64-mingw32-g++{{- end }}
+        {{- end }}
+```