Add new datasource to get GitHub App token (#1671)

* Add new datasource to get GitHub App token

* Add new datasource to get GitHub App token

* Fix merge error

---------

Co-authored-by: Keegan Campbell <[email protected]>

Author: phillebaba

examples/app_token/main.tf

@@ -0,0 +1,15 @@
+terraform {
+  required_providers {
+    github = {
+      source = "integrations/github"
+    }
+  }
+}
+
+provider "github" {}
+
+data "github_app_token" "this" {
+  app_id          = var.app_id
+  installation_id = var.installation_id
+  pem_file        = file(var.pem_file_path)
+}

examples/app_token/variables.tf

@@ -0,0 +1,11 @@
+variable "app_id" {
+  type = string
+}
+
+variable "installation_id" {
+  type = string
+}
+
+variable "pem_file_path" {
+  type = string
+}

github/data_source_github_app_token.go

@@ -0,0 +1,63 @@
+package github
+
+import (
+	"strings"
+
+	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
+)
+
+func dataSourceGithubAppToken() *schema.Resource {
+	return &schema.Resource{
+		Read: dataSourceGithubAppTokenRead,
+
+		Schema: map[string]*schema.Schema{
+			"app_id": {
+				Type:        schema.TypeString,
+				Required:    true,
+				Description: descriptions["app_auth.id"],
+			},
+			"installation_id": {
+				Type:        schema.TypeString,
+				Required:    true,
+				Description: descriptions["app_auth.installation_id"],
+			},
+			"pem_file": {
+				Type:        schema.TypeString,
+				Required:    true,
+				Description: descriptions["app_auth.pem_file"],
+			},
+			"token": {
+				Type:        schema.TypeString,
+				Computed:    true,
+				Sensitive:   true,
+				Description: "The generated token from the credentials.",
+			},
+		},
+	}
+}
+
+func dataSourceGithubAppTokenRead(d *schema.ResourceData, meta interface{}) error {
+	appID := d.Get("app_id").(string)
+	installationID := d.Get("installation_id").(string)
+	pemFile := d.Get("pem_file").(string)
+
+	baseURL := meta.(*Owner).v3client.BaseURL.String()
+
+	// The Go encoding/pem package only decodes PEM formatted blocks
+	// that contain new lines. Some platforms, like Terraform Cloud,
+	// do not support new lines within Environment Variables.
+	// Any occurrence of \n in the `pem_file` argument's value
+	// (explicit value, or default value taken from
+	// GITHUB_APP_PEM_FILE Environment Variable) is replaced with an
+	// actual new line character before decoding.
+	pemFile = strings.Replace(pemFile, `\n`, "\n", -1)
+
+	token, err := GenerateOAuthTokenFromApp(baseURL, appID, installationID, pemFile)
+	if err != nil {
+		return err
+	}
+	d.Set("token", token)
+	d.SetId("id")
+
+	return nil
+}

github/data_source_github_app_token_test.go

@@ -0,0 +1,66 @@
+package github
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"testing"
+
+	"github.com/google/go-github/v53/github"
+	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAccGithubAppTokenDataSource(t *testing.T) {
+	expectedAccessToken := "W+2e/zjiMTweDAr2b35toCF+h29l7NW92rJIPvFrCJQK"
+
+	owner := "test-owner"
+
+	pemData, err := os.ReadFile(testGitHubAppPrivateKeyFile)
+	assert.Nil(t, err)
+
+	t.Run("creates a application token without error", func(t *testing.T) {
+		ts := githubApiMock([]*mockResponse{
+			{
+				ExpectedUri: fmt.Sprintf("/api/v3/app/installations/%s/access_tokens", testGitHubAppInstallationID),
+				ExpectedHeaders: map[string]string{
+					"Accept": "application/vnd.github.v3+json",
+				},
+				ResponseBody: fmt.Sprintf(`{"token": "%s"}`, expectedAccessToken),
+				StatusCode:   201,
+			},
+		})
+		defer ts.Close()
+
+		httpCl := http.DefaultClient
+		httpCl.Transport = http.DefaultTransport
+
+		client := github.NewClient(httpCl)
+		u, _ := url.Parse(ts.URL + "/")
+		client.BaseURL = u
+
+		meta := &Owner{
+			name:     owner,
+			v3client: client,
+		}
+
+		testSchema := map[string]*schema.Schema{
+			"app_id":          {Type: schema.TypeString},
+			"installation_id": {Type: schema.TypeString},
+			"pem_file":        {Type: schema.TypeString},
+			"token":           {Type: schema.TypeString},
+		}
+
+		schema := schema.TestResourceDataRaw(t, testSchema, map[string]interface{}{
+			"app_id":          testGitHubAppID,
+			"installation_id": testGitHubAppInstallationID,
+			"pem_file":        string(pemData),
+			"token":           "",
+		})
+
+		err := dataSourceGithubAppTokenRead(schema, meta)
+		assert.Nil(t, err)
+		assert.Equal(t, expectedAccessToken, schema.Get("token"))
+	})
+}

github/provider.go

@@ -167,6 +167,7 @@ func Provider() terraform.ResourceProvider {
 			"github_actions_secrets":                                                dataSourceGithubActionsSecrets(),
 			"github_actions_variables":                                              dataSourceGithubActionsVariables(),
 			"github_app":                                                            dataSourceGithubApp(),
+			"github_app_token":                                                      dataSourceGithubAppToken(),
 			"github_branch":                                                         dataSourceGithubBranch(),
 			"github_branch_protection_rules":                                        dataSourceGithubBranchProtectionRules(),
 			"github_collaborators":                                                  dataSourceGithubCollaborators(),

website/docs/d/app_token.html.markdown

@@ -0,0 +1,36 @@
+---
+layout: "github"
+page_title: "GitHub: github_app_token"
+description: |-
+  Generate a GitHub APP JWT.
+---
+
+# github\_app\_token
+
+Use this data source to generate a [GitHub App JWT](https://docs.github.com/en/apps/creating-github-apps/authenticating-with-a-github-app/generating-a-json-web-token-jwt-for-a-github-app).
+
+## Example Usage
+
+```hcl
+data "github_app_token" "this" {
+  app_id          = "123456"
+  installation_id = "78910"
+  pem_file        = file("foo/bar.pem")
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `app_id` - (Required) This is the ID of the GitHub App.
+
+* `installation_id` - (Required) This is the ID of the GitHub App installation.
+
+* `pem_file` - (Required) This is the contents of the GitHub App private key PEM file.
+
+## Attribute Reference
+
+The following additional attributes are exported:
+
+* `token` - The generated GitHub APP JWT.

website/github.erb

@@ -52,6 +52,9 @@
             <li>
               <a href="/docs/providers/github/d/app.html">github_app</a>
             </li>
+            <li>
+              <a href="/docs/providers/github/d/app_token.html"></a>
+            </li>
             <li>
               <a href="/docs/providers/github/d/branch.html">github_branch</a>
             </li>