feat: support environment variables on ldflags

Supports passing environment variables to ldflags by using .Env.VARNAME.

Closes #426

docs/000-introduction.md

@@ -22,5 +22,5 @@ that and rewrote the whole thing in Go.
 There are three ways to get going.
 
 1. Install Goreleaser via go get (`goreleaser` command will be globally available) `go get github.com/goreleaser/goreleaser`
-2. On a Mac use [Homebrew](https://github.com/goreleaser/homebrew-tap).
-3. Install directly [from the binaries](https://github.com/goreleaser/goreleaser/releases/latest).
+1. On a Mac use [Homebrew](https://github.com/goreleaser/homebrew-tap).
+1. Install directly [from the binaries](https://github.com/goreleaser/goreleaser/releases/latest).

docs/040-project.md

@@ -5,7 +5,6 @@ title: Project Name
 The project name is used in the name of the Brew formula, archives, etc.
 If none is given, it will be inferred from the name of the Git project.
 
-
 ```yaml
 # .goreleaser.yml
 project_name: myproject

docs/050-build.md

@@ -78,3 +78,19 @@ builds:
       pre: rice embed-go
       post: ./script.sh
 ```
+
+## Passing environment variables to ldflags
+
+You can do that by using `{{ .Env.VARIABLE_NAME }}` in the template, for
+example:
+
+```yaml
+builds:
+  - ldflags: -s -w -X "main.goversion={{.Env.GOVERSION}}"
+```
+
+Then you can run:
+
+```console
+GOVERSION=$(go version) goreleaser
+```

pipeline/build/ldflags.go

@@ -2,6 +2,8 @@ package build
 
 import (
 	"bytes"
+	"os"
+	"strings"
 	"text/template"
 	"time"
 
@@ -14,6 +16,7 @@ type ldflagsData struct {
 	Tag     string
 	Commit  string
 	Version string
+	Env     map[string]string
 }
 
 func ldflags(ctx *context.Context, build config.Build) (string, error) {
@@ -22,6 +25,7 @@ func ldflags(ctx *context.Context, build config.Build) (string, error) {
 		Tag:     ctx.Git.CurrentTag,
 		Version: ctx.Version,
 		Date:    time.Now().UTC().Format(time.RFC3339),
+		Env:     loadEnvs(),
 	}
 	var out bytes.Buffer
 	t, err := template.New("ldflags").Parse(build.Ldflags)
@@ -31,3 +35,12 @@ func ldflags(ctx *context.Context, build config.Build) (string, error) {
 	err = t.Execute(&out, data)
 	return out.String(), err
 }
+
+func loadEnvs() map[string]string {
+	r := map[string]string{}
+	for _, e := range os.Environ() {
+		env := strings.Split(e, "=")
+		r[env[0]] = env[1]
+	}
+	return r
+}

pipeline/build/ldflags_test.go

@@ -1,6 +1,7 @@
 package build
 
 import (
+	"os"
 	"testing"
 
 	"github.com/goreleaser/goreleaser/config"
@@ -12,10 +13,12 @@ func TestLdFlagsFullTemplate(t *testing.T) {
 	var config = config.Project{
 		Builds: []config.Build{
 			{
-				Ldflags: "-s -w -X main.version={{.Version}} -X main.tag={{.Tag}} -X main.date={{.Date}} -X main.commit={{.Commit}}",
+				Ldflags: `-s -w -X main.version={{.Version}} -X main.tag={{.Tag}} -X main.date={{.Date}} -X main.commit={{.Commit}} -X "main.foo={{.Env.FOO}}"`,
 			},
 		},
 	}
+	os.Setenv("FOO", "123")
+	defer os.Unsetenv("FOO")
 	var ctx = &context.Context{
 		Git: context.GitInfo{
 			CurrentTag: "v1.2.3",
@@ -31,6 +34,7 @@ func TestLdFlagsFullTemplate(t *testing.T) {
 	assert.Contains(t, flags, "-X main.tag=v1.2.3")
 	assert.Contains(t, flags, "-X main.commit=123")
 	assert.Contains(t, flags, "-X main.date=")
+	assert.Contains(t, flags, `-X "main.foo=123"`)
 }
 
 func TestInvalidTemplate(t *testing.T) {