Use Gazelle's go_env in @rules_go//go (#3909)

MODULE.bazel

@@ -27,7 +27,7 @@ use_repo(
 
 register_toolchains("@go_toolchains//:all")
 
-bazel_dep(name = "gazelle", version = "0.34.0")
+bazel_dep(name = "gazelle", version = "0.36.0")
 
 go_deps = use_extension("@gazelle//:extensions.bzl", "go_deps")
 go_deps.from_file(go_mod = "//:go.mod")
@@ -42,4 +42,6 @@ use_repo(
     "org_golang_google_protobuf",
     "org_golang_x_net",
     "org_golang_x_tools",
+    # Exported by gazelle specifically for rules_go.
+    "bazel_gazelle_go_repository_config",
 )

docs/go/core/bzlmod.md

@@ -205,6 +205,21 @@ A dependency can be added via
 bazel run @rules_go//go get golang.org/x/text@v0.3.2
 ```
 
+### Environment variables
+
+Environment variables (such as `GOPROXY` and `GOPRIVATE`) required for fetching Go dependencies can be set as follows:
+
+```starlark
+go_deps.config(
+   go_env = {
+      "GOPRIVATE": "...",
+   },
+)
+```
+
+Variables set in this way are used by `go_deps` as well as `@rules_go//go`, with other variables inheriting their value from the host environment.
+`go_env` does *not* affect Go build actions.
+
 ### Overrides
 
 The root module can override certain aspects of the dependency resolution performed by the `go_deps` extension.

go/private/common.bzl

@@ -262,3 +262,6 @@ _RULES_GO_RAW_REPO_NAME = str(Label("//:unused"))[:-len("//:unused")]
 # not start with a "@", so we need to add it.
 RULES_GO_REPO_NAME = _RULES_GO_RAW_REPO_NAME if _RULES_GO_RAW_REPO_NAME.startswith("@") else "@" + _RULES_GO_RAW_REPO_NAME
 RULES_GO_STDLIB_PREFIX = RULES_GO_REPO_NAME + "//stdlib:"
+
+# TODO: Remove the "and" once the rules_go repo itself uses Bzlmod.
+RULES_GO_IS_BZLMOD_REPO = _RULES_GO_RAW_REPO_NAME.lstrip("@") != "io_bazel_rules_go" and _RULES_GO_RAW_REPO_NAME.lstrip("@")

go/tools/go_bin_runner/BUILD.bazel

@@ -1,6 +1,7 @@
 # gazelle:exclude
 
 load("//go:def.bzl", "go_binary", "go_library")
+load("//go/private:common.bzl", "RULES_GO_IS_BZLMOD_REPO")
 load("//go/private/rules:go_bin_for_host.bzl", "go_bin_for_host")
 
 go_bin_for_host(
@@ -12,7 +13,6 @@ go_library(
     name = "go_bin_runner_lib",
     srcs = [
         "main.go",
-        "process.go",
     ],
     importpath = "github.com/bazelbuild/rules_go/go/tools/go_bin_runner",
     visibility = ["//visibility:private"],
@@ -28,11 +28,14 @@ go_binary(
         "@platforms//os:windows": "bin/go.exe",
         "//conditions:default": "bin/go",
     }),
-    data = [":go_bin_for_host"],
+    data = [":go_bin_for_host"] + (
+        ["@bazel_gazelle_go_repository_config//:config.json"] if RULES_GO_IS_BZLMOD_REPO else []
+    ),
     embed = [":go_bin_runner_lib"],
     visibility = ["//go:__pkg__"],
     x_defs = {
         "GoBinRlocationPath": "$(rlocationpath :go_bin_for_host)",
+        "ConfigRlocationPath": "$(rlocationpath @bazel_gazelle_go_repository_config//:config.json)" if RULES_GO_IS_BZLMOD_REPO else "WORKSPACE",
     },
 )
 

go/tools/go_bin_runner/main.go

@@ -1,41 +1,92 @@
 package main
 
 import (
+	"encoding/json"
 	"log"
 	"os"
+	"os/exec"
 	"path/filepath"
-	"strings"
 
 	"github.com/bazelbuild/rules_go/go/runfiles"
 )
 
 var GoBinRlocationPath = "not set"
+var ConfigRlocationPath = "not set"
+
+// Produced by gazelle's go_deps extension.
+type Config struct {
+	GoEnv map[string]string `json:"go_env"`
+}
 
 func main() {
 	goBin, err := runfiles.Rlocation(GoBinRlocationPath)
 	if err != nil {
 		log.Fatal(err)
 	}
-	// The go binary lies at $GOROOT/bin/go.
-	goRoot, err := filepath.Abs(filepath.Dir(filepath.Dir(goBin)))
+
+	cfg, err := parseConfig()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	env, err := getGoEnv(goBin, cfg)
 	if err != nil {
 		log.Fatal(err)
 	}
 
+	args := append([]string{goBin}, os.Args[1:]...)
+	log.Fatal(runProcess(args, env, os.Getenv("BUILD_WORKING_DIRECTORY")))
+}
+
+func parseConfig() (Config, error) {
+	var cfg *Config
+	// Special value set when rules_go is loaded as a WORKSPACE repo, in which
+	// the cfg file isn't available from Gazelle.
+	if ConfigRlocationPath == "WORKSPACE" {
+		return Config{}, nil
+	}
+	cfgJsonPath, err := runfiles.Rlocation(ConfigRlocationPath)
+	if err != nil {
+		return Config{}, err
+	}
+	cfgJson, err := os.ReadFile(cfgJsonPath)
+	if err != nil {
+		return Config{}, err
+	}
+	err = json.Unmarshal(cfgJson, &cfg)
+	if err != nil {
+		return Config{}, err
+	}
+	return *cfg, nil
+}
+
+func getGoEnv(goBin string, cfg Config) ([]string, error) {
 	env := os.Environ()
-	var filteredEnv []string
-	for i := 0; i < len(env); i++ {
-		if !strings.HasPrefix(env[i], "GOROOT=") {
-			filteredEnv = append(filteredEnv, env[i])
-		}
+	for k, v := range cfg.GoEnv {
+		env = append(env, k+"="+v)
 	}
-	filteredEnv = append(filteredEnv, "GOROOT="+goRoot)
 
-	err = os.Chdir(os.Getenv("BUILD_WORKING_DIRECTORY"))
+	// The go binary lies at $GOROOT/bin/go.
+	goRoot, err := filepath.Abs(filepath.Dir(filepath.Dir(goBin)))
 	if err != nil {
-		log.Fatal(err)
+		return nil, err
 	}
 
-	args := append([]string{goBin}, os.Args[1:]...)
-	log.Fatal(ReplaceWithProcess(args, filteredEnv))
+	// Override GOROOT to point to the hermetic Go SDK.
+	return append(env, "GOROOT="+goRoot), nil
+}
+
+func runProcess(args, env []string, dir string) error {
+	cmd := exec.Command(args[0], args[1:]...)
+	cmd.Dir = dir
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.Env = env
+	err := cmd.Run()
+	if exitErr, ok := err.(*exec.ExitError); ok {
+		os.Exit(exitErr.ExitCode())
+	} else if err == nil {
+		os.Exit(0)
+	}
+	return err
 }

tests/bcr/.bazelversion

@@ -1 +1 @@
-6.0.0
+6.4.0

tests/bcr/BUILD.bazel

@@ -63,8 +63,8 @@ go_test(
 )
 
 sh_test(
-    name = "go_version_test",
-    srcs = ["go_version_test.sh"],
+    name = "go_tool_test",
+    srcs = ["go_tool_test.sh"],
     data = ["@my_rules_go//go"],
     env = {"GO_TOOL_RLOCATION": "$(rlocationpath @my_rules_go//go)"},
     deps = ["@bazel_tools//tools/bash/runfiles"],

tests/bcr/MODULE.bazel

@@ -50,4 +50,9 @@ go_deps.module(
     sum = "h1:pnP7OclFFFgFi4VHQDQDaoXUVauOFyktqTsqqgzFKbc=",
     version = "v1.40.1",
 )
+
+# Read in go_tool_test.sh.
+go_deps.config(
+    go_env = {"GOPRIVATE": "example.com"},
+)
 use_repo(go_deps, "org_golang_google_grpc")

tests/bcr/go_version_test.sh → tests/bcr/go_tool_test.sh

@@ -17,3 +17,4 @@ runfiles_export_envvars
 # Simulate a bazel run environment.
 export BUILD_WORKING_DIRECTORY=$(pwd)
 [[ "$("$GO_TOOL" version)" =~ ^go ]]
+[[ "$("$GO_TOOL" env GOPRIVATE)" == example.com ]]