feat: respect existing RAILS_ENV and SECRET_KEY_BASE

This change allows users to set alternative values for RAILS_ENV and SECRET_KEY_BASE when precompiling assets.

Closes #200

precompile_process.go

@@ -43,11 +43,35 @@ func (p PrecompileProcess) Execute(workingDir string) error {
 		Args:   args,
 		Stdout: p.logger.ActionWriter,
 		Stderr: p.logger.ActionWriter,
-		Env:    append(os.Environ(), "RAILS_ENV=production", "SECRET_KEY_BASE=dummy"),
+		Env:    processPrecompileEnv(os.Environ()),
 	})
 	if err != nil {
 		return fmt.Errorf("failed to execute bundle exec output:\n%s\nerror: %s", buffer.String(), err)
 	}
 
 	return nil
 }
+
+func processPrecompileEnv(env []string) []string {
+	hasRailsEnv := false
+	hasSecretKeyBase := false
+	for _, pair := range env {
+		if strings.HasPrefix(pair, "RAILS_ENV=") {
+			hasRailsEnv = true
+		}
+
+		if strings.HasPrefix(pair, "SECRET_KEY_BASE=") {
+			hasSecretKeyBase = true
+		}
+	}
+
+	if !hasRailsEnv {
+		env = append(env, "RAILS_ENV=production")
+	}
+
+	if !hasSecretKeyBase {
+		env = append(env, "SECRET_KEY_BASE=dummy")
+	}
+
+	return env
+}

precompile_process_test.go

@@ -25,6 +25,11 @@ func testPrecompileProcess(t *testing.T, context spec.G, it spec.S) {
 			executable *fakes.Executable
 
 			precompileProcess railsassets.PrecompileProcess
+
+			hasRailsEnv      bool
+			hasSecretKeyBase bool
+			railsEnv         string
+			secretKeyBase    string
 		)
 
 		it.Before(func() {
@@ -43,9 +48,20 @@ func testPrecompileProcess(t *testing.T, context spec.G, it spec.S) {
 			logger := scribe.NewEmitter(bytes.NewBuffer(nil))
 
 			precompileProcess = railsassets.NewPrecompileProcess(executable, logger)
+
+			railsEnv, hasRailsEnv = os.LookupEnv("RAILS_ENV")
+			secretKeyBase, hasSecretKeyBase = os.LookupEnv("SECRET_KEY_BASE")
 		})
 
 		it.After(func() {
+			if hasRailsEnv {
+				os.Setenv("RAILS_ENV", railsEnv)
+			}
+
+			if hasSecretKeyBase {
+				os.Setenv("SECRET_KEY_BASE", secretKeyBase)
+			}
+
 			Expect(os.RemoveAll(workingDir)).To(Succeed())
 		})
 
@@ -59,6 +75,28 @@ func testPrecompileProcess(t *testing.T, context spec.G, it spec.S) {
 			Expect(executions[0].Env).To(ContainElement("SECRET_KEY_BASE=dummy"))
 		})
 
+		it("runs the bundle exec assets:precompile process while respecting RAILS_ENV", func() {
+			os.Setenv("RAILS_ENV", "staging")
+			err := precompileProcess.Execute(workingDir)
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(executions).To(HaveLen(1))
+			Expect(executions[0].Args).To(Equal([]string{"exec", "rails", "assets:precompile", "assets:clean"}))
+			Expect(executions[0].Env).To(ContainElement("RAILS_ENV=staging"))
+			Expect(executions[0].Env).To(ContainElement("SECRET_KEY_BASE=dummy"))
+		})
+
+		it("runs the bundle exec assets:precompile process while respecting SECRET_KEY_BASE", func() {
+			os.Setenv("SECRET_KEY_BASE", "dummy2")
+			err := precompileProcess.Execute(workingDir)
+			Expect(err).NotTo(HaveOccurred())
+
+			Expect(executions).To(HaveLen(1))
+			Expect(executions[0].Args).To(Equal([]string{"exec", "rails", "assets:precompile", "assets:clean"}))
+			Expect(executions[0].Env).To(ContainElement("RAILS_ENV=production"))
+			Expect(executions[0].Env).To(ContainElement("SECRET_KEY_BASE=dummy2"))
+		})
+
 		context("failure cases", func() {
 			context("when bundle exec fails", func() {
 				it.Before(func() {