Expose go env variables as action outputs (#791)

* feature implementation - output go env

* update action.yml

* fix action.yml

---------

Co-authored-by: mahabaleshwars <147705296+mahabaleshwars@users.noreply.github.com>

src/constants.ts

@@ -4,5 +4,14 @@ export enum State {
 }
 
 export enum Outputs {
-  CacheHit = 'cache-hit'
+  CacheHit = 'cache-hit',
+  GoPath = 'go-path',
+  GoBin = 'go-bin',
+  GoBinPath = 'go-bin-path',
+  GoRoot = 'go-root',
+  GoCache = 'go-cache',
+  GoModCache = 'go-mod-cache',
+  GoOs = 'go-os',
+  GoArch = 'go-arch',
+  GoToolDir = 'go-tool-dir'
 }

src/main.ts

@@ -10,6 +10,7 @@ import cp from 'child_process';
 import fs from 'fs';
 import os from 'os';
 import {Architecture} from './types.js';
+import {Outputs} from './constants.js';
 
 export async function run() {
   try {
@@ -82,6 +83,11 @@ export async function run() {
 
     const goPath = await io.which('go');
     const goVersion = (cp.execSync(`${goPath} version`) || '').toString();
+    const goEnvJson = readGoEnv(goPath);
+
+    if (goEnvJson) {
+      setGoEnvOutputs(goEnvJson);
+    }
 
     if (cache && isCacheFeatureAvailable()) {
       const packageManager = 'default';
@@ -119,6 +125,57 @@ export async function run() {
   }
 }
 
+export function readGoEnv(goPath: string): Record<string, string> | undefined {
+  try {
+    const rawGoEnv = cp.execFileSync(goPath, ['env', '-json'], {
+      encoding: 'utf8',
+      stdio: ['ignore', 'pipe', 'pipe']
+    });
+    const parsed: unknown = JSON.parse(rawGoEnv);
+
+    if (
+      typeof parsed !== 'object' ||
+      parsed === null ||
+      Array.isArray(parsed)
+    ) {
+      throw new Error("'go env -json' did not return a JSON object");
+    }
+
+    return parsed as Record<string, string>;
+  } catch (error) {
+    core.info(
+      `Unable to read 'go env -json', the Go environment outputs will not be set: ${
+        (error as Error).message
+      }`
+    );
+    return undefined;
+  }
+}
+
+const goEnvOutputs: ReadonlyArray<[Outputs, string]> = [
+  [Outputs.GoPath, 'GOPATH'],
+  [Outputs.GoBin, 'GOBIN'],
+  [Outputs.GoRoot, 'GOROOT'],
+  [Outputs.GoCache, 'GOCACHE'],
+  [Outputs.GoModCache, 'GOMODCACHE'],
+  [Outputs.GoOs, 'GOOS'],
+  [Outputs.GoArch, 'GOARCH'],
+  [Outputs.GoToolDir, 'GOTOOLDIR']
+];
+
+export function setGoEnvOutputs(goEnv: Record<string, string>): void {
+  for (const [output, variable] of goEnvOutputs) {
+    core.setOutput(output, goEnv[variable] ?? '');
+  }
+
+  core.setOutput(Outputs.GoBinPath, goEnv['GOBIN'] || goPathBin(goEnv));
+}
+
+function goPathBin(goEnv: Record<string, string>): string {
+  const goPath = (goEnv['GOPATH'] ?? '').split(path.delimiter)[0];
+  return goPath ? path.join(goPath, 'bin') : '';
+}
+
 export async function addBinToPath(): Promise<boolean> {
   let added = false;
   const g = await io.which('go');