Inject GitHub host to be able to clone from another GitHub instance (#922)

* Adding the ability to specify the GitHub Server URL and allowing for it to differ from the Actions workflow host

* Adding tests for injecting the GitHub URL

* Addressing code review comments for PR #922

8 files changed, 83 insertions, 33 deletions

diff --git a/src/git-auth-helper.ts b/src/git-auth-helper.ts
index 8a1c7c3..3c6db8e 100644
--- a/src/git-auth-helper.ts
+++ b/src/git-auth-helper.ts
@@ -52,7 +52,7 @@ class GitAuthHelper {
     this.settings = gitSourceSettings || (({} as unknown) as IGitSourceSettings)
 
     // Token auth header
-    const serverUrl = urlHelper.getServerUrl()
+    const serverUrl = urlHelper.getServerUrl(this.settings.githubServerUrl)
     this.tokenConfigKey = `http.${serverUrl.origin}/.extraheader` // "origin" is SCHEME://HOSTNAME[:PORT]
     const basicCredential = Buffer.from(
       `x-access-token:${this.settings.authToken}`,
diff --git a/src/git-source-provider.ts b/src/git-source-provider.ts
index 545a7a3..48f20da 100644
--- a/src/git-source-provider.ts
+++ b/src/git-source-provider.ts
@@ -93,7 +93,8 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
         settings.repositoryName,
         settings.ref,
         settings.commit,
-        settings.repositoryPath
+        settings.repositoryPath,
+        settings.githubServerUrl
       )
       return
     }
@@ -138,7 +139,8 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
         settings.ref = await githubApiHelper.getDefaultBranch(
           settings.authToken,
           settings.repositoryOwner,
-          settings.repositoryName
+          settings.repositoryName,
+          settings.githubServerUrl
         )
       }
       core.endGroup()
@@ -232,7 +234,8 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
       settings.repositoryOwner,
       settings.repositoryName,
       settings.ref,
-      settings.commit
+      settings.commit,
+      settings.githubServerUrl
     )
   } finally {
     // Remove auth
diff --git a/src/git-source-settings.ts b/src/git-source-settings.ts
index 6fa3960..2da5622 100644
--- a/src/git-source-settings.ts
+++ b/src/git-source-settings.ts
@@ -83,4 +83,9 @@ export interface IGitSourceSettings {
    * Indicates whether to add repositoryPath as safe.directory in git global config
    */
   setSafeDirectory: boolean
+
+  /**
+   * User override on the GitHub Server/Host URL that hosts the repository to be cloned
+   */
+  githubServerUrl: string | undefined
 }
diff --git a/src/github-api-helper.ts b/src/github-api-helper.ts
index 45b979a..2124a86 100644
--- a/src/github-api-helper.ts
+++ b/src/github-api-helper.ts
@@ -1,13 +1,12 @@
 import * as assert from 'assert'
 import * as core from '@actions/core'
 import * as fs from 'fs'
-import * as github from '@actions/github'
 import * as io from '@actions/io'
 import * as path from 'path'
 import * as retryHelper from './retry-helper'
 import * as toolCache from '@actions/tool-cache'
 import {default as uuid} from 'uuid/v4'
-import {Octokit} from '@octokit/rest'
+import {getOctokit, Octokit} from './octokit-provider'
 
 const IS_WINDOWS = process.platform === 'win32'
 
@@ -17,18 +16,19 @@ export async function downloadRepository(
   repo: string,
   ref: string,
   commit: string,
-  repositoryPath: string
+  repositoryPath: string,
+  baseUrl?: string
 ): Promise<void> {
   // Determine the default branch
   if (!ref && !commit) {
     core.info('Determining the default branch')
-    ref = await getDefaultBranch(authToken, owner, repo)
+    ref = await getDefaultBranch(authToken, owner, repo, baseUrl)
   }
 
   // Download the archive
   let archiveData = await retryHelper.execute(async () => {
     core.info('Downloading the archive')
-    return await downloadArchive(authToken, owner, repo, ref, commit)
+    return await downloadArchive(authToken, owner, repo, ref, commit, baseUrl)
   })
 
   // Write archive to disk
@@ -79,11 +79,12 @@ export async function downloadRepository(
 export async function getDefaultBranch(
   authToken: string,
   owner: string,
-  repo: string
+  repo: string,
+  baseUrl?: string
 ): Promise<string> {
   return await retryHelper.execute(async () => {
     core.info('Retrieving the default branch name')
-    const octokit = new github.GitHub(authToken)
+    const octokit = getOctokit(authToken, {baseUrl: baseUrl})
     let result: string
     try {
       // Get the default branch from the repo info
@@ -121,9 +122,10 @@ async function downloadArchive(
   owner: string,
   repo: string,
   ref: string,
-  commit: string
+  commit: string,
+  baseUrl?: string
 ): Promise<Buffer> {
-  const octokit = new github.GitHub(authToken)
+  const octokit = getOctokit(authToken, {baseUrl: baseUrl})
   const params: Octokit.ReposGetArchiveLinkParams = {
     owner: owner,
     repo: repo,
diff --git a/src/input-helper.ts b/src/input-helper.ts
index 8c2f901..237b06a 100644
--- a/src/input-helper.ts
+++ b/src/input-helper.ts
@@ -125,5 +125,10 @@ export async function getInputs(): Promise<IGitSourceSettings> {
   // Set safe.directory in git global config.
   result.setSafeDirectory =
     (core.getInput('set-safe-directory') || 'true').toUpperCase() === 'TRUE'
+
+  // Determine the GitHub URL that the repository is being hosted from
+  result.githubServerUrl = core.getInput('github-server-url')
+  core.debug(`GitHub Host URL = ${result.githubServerUrl}`)
+
   return result
 }
diff --git a/src/octokit-provider.ts b/src/octokit-provider.ts
new file mode 100644
index 0000000..4fb1285
--- /dev/null
+++ b/src/octokit-provider.ts
@@ -0,0 +1,23 @@
+import * as github from '@actions/github'
+import {Octokit} from '@octokit/rest'
+import {getServerApiUrl} from './url-helper'
+
+// Centralize all Octokit references by re-exporting
+export {Octokit} from '@octokit/rest'
+
+export type OctokitOptions = {
+  baseUrl?: string
+  userAgent?: string
+}
+
+export function getOctokit(authToken: string, opts: OctokitOptions) {
+  const options: Octokit.Options = {
+    baseUrl: getServerApiUrl(opts.baseUrl)
+  }
+
+  if (opts.userAgent) {
+    options.userAgent = opts.userAgent
+  }
+
+  return new github.GitHub(authToken, options)
+}
diff --git a/src/ref-helper.ts b/src/ref-helper.ts
index 209f49d..ce875fc 100644
--- a/src/ref-helper.ts
+++ b/src/ref-helper.ts
@@ -1,7 +1,8 @@
-import {URL} from 'url'
 import {IGitCommandManager} from './git-command-manager'
 import * as core from '@actions/core'
 import * as github from '@actions/github'
+import {getOctokit} from './octokit-provider'
+import {isGhes} from './url-helper'
 
 export const tagsRefSpec = '+refs/tags/*:refs/tags/*'
 
@@ -183,11 +184,12 @@ export async function checkCommitInfo(
   repositoryOwner: string,
   repositoryName: string,
   ref: string,
-  commit: string
+  commit: string,
+  baseUrl?: string
 ): Promise<void> {
   try {
     // GHES?
-    if (isGhes()) {
+    if (isGhes(baseUrl)) {
       return
     }
 
@@ -243,7 +245,8 @@ export async function checkCommitInfo(
       core.debug(
         `Expected head sha ${expectedHeadSha}; actual head sha ${actualHeadSha}`
       )
-      const octokit = new github.GitHub(token, {
+      const octokit = getOctokit(token, {
+        baseUrl: baseUrl,
         userAgent: `actions-checkout-tracepoint/1.0 (code=STALE_MERGE;owner=${repositoryOwner};repo=${repositoryName};pr=${fromPayload(
           'number'
         )};run_id=${
@@ -276,10 +279,3 @@ function select(obj: any, path: string): any {
   const key = path.substr(0, i)
   return select(obj[key], path.substr(i + 1))
 }
-
-function isGhes(): boolean {
-  const ghUrl = new URL(
-    process.env['GITHUB_SERVER_URL'] || 'https://github.com'
-  )
-  return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM'
-}
diff --git a/src/url-helper.ts b/src/url-helper.ts
index 05f1cbd..6807b7f 100644
--- a/src/url-helper.ts
+++ b/src/url-helper.ts
@@ -1,6 +1,6 @@
 import * as assert from 'assert'
-import {IGitSourceSettings} from './git-source-settings'
 import {URL} from 'url'
+import {IGitSourceSettings} from './git-source-settings'
 
 export function getFetchUrl(settings: IGitSourceSettings): string {
   assert.ok(
@@ -8,7 +8,7 @@ export function getFetchUrl(settings: IGitSourceSettings): string {
     'settings.repositoryOwner must be defined'
   )
   assert.ok(settings.repositoryName, 'settings.repositoryName must be defined')
-  const serviceUrl = getServerUrl()
+  const serviceUrl = getServerUrl(settings.githubServerUrl)
   const encodedOwner = encodeURIComponent(settings.repositoryOwner)
   const encodedName = encodeURIComponent(settings.repositoryName)
   if (settings.sshKey) {
@@ -19,11 +19,27 @@ export function getFetchUrl(settings: IGitSourceSettings): string {
   return `${serviceUrl.origin}/${encodedOwner}/${encodedName}`
 }
 
-export function getServerUrl(): URL {
-  // todo: remove GITHUB_URL after support for GHES Alpha is no longer needed
-  return new URL(
-    process.env['GITHUB_SERVER_URL'] ||
-      process.env['GITHUB_URL'] ||
-      'https://github.com'
-  )
+export function getServerUrl(url?: string): URL {
+  let urlValue =
+    url && url.trim().length > 0
+      ? url
+      : process.env['GITHUB_SERVER_URL'] || 'https://github.com'
+  return new URL(urlValue)
+}
+
+export function getServerApiUrl(url?: string): string {
+  let apiUrl = 'https://api.github.com'
+
+  if (isGhes(url)) {
+    const serverUrl = getServerUrl(url)
+    apiUrl = new URL(`${serverUrl.origin}/api/v3`).toString()
+  }
+
+  return apiUrl
+}
+
+export function isGhes(url?: string): boolean {
+  const ghUrl = getServerUrl(url)
+
+  return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM'
 }