use CreateInstallationToken

internal/githubclient/client.go

@@ -1,13 +1,12 @@
 package githubclient
 
 import (
+	"context"
 	"crypto/rsa"
 	"crypto/x509"
-	"encoding/json"
 	"encoding/pem"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"strconv"
 	"time"
@@ -96,36 +95,44 @@ func generateAppJWT(appID string, issuedAt time.Time, privateKeyPEM []byte) (str
 }
 
 func getInstallationAccessToken(baseURL, appJWT, installationID string) (string, error) {
-	url := fmt.Sprintf("%s/app/installations/%s/access_tokens", baseURL, installationID)
+	tc := &http.Client{
+		Transport: &jwtTransport{
+			token: appJWT,
+			rt:    http.DefaultTransport,
+		},
+		Timeout: 30 * time.Second,
+	}
 
-	req, err := http.NewRequest("POST", url, nil)
+	client, err := github.NewClient(tc).WithEnterpriseURLs(baseURL, baseURL)
 	if err != nil {
-		return "", fmt.Errorf("failed to create request: %v", err)
+		return "", fmt.Errorf("failed to create github client: %v", err)
 	}
 
-	req.Header.Set("Authorization", "Bearer "+appJWT)
-	req.Header.Set("Accept", "application/vnd.github.v3+json")
-	req.Header.Set("User-Agent", "terraform-provider-kw-github")
-
-	client := &http.Client{Timeout: 30 * time.Second}
-	resp, err := client.Do(req)
+	installationIDInt, err := strconv.ParseInt(installationID, 10, 64)
 	if err != nil {
-		return "", fmt.Errorf("failed to make request: %v", err)
+		return "", fmt.Errorf("invalid installation ID: %v", err)
 	}
-	defer resp.Body.Close()
 
-	if resp.StatusCode != http.StatusCreated {
-		body, _ := io.ReadAll(resp.Body)
-		return "", fmt.Errorf("failed to get access token: %s - %s", resp.Status, string(body))
+	token, _, err := client.Apps.CreateInstallationToken(
+		context.Background(),
+		installationIDInt,
+		&github.InstallationTokenOptions{},
+	)
+	if err != nil {
+		return "", fmt.Errorf("failed to create installation token: %v", err)
 	}
 
-	var tokenResp struct {
-		Token string `json:"token"`
-	}
+	return token.GetToken(), nil
+}
 
-	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
-		return "", fmt.Errorf("failed to decode response: %v", err)
-	}
+type jwtTransport struct {
+	token string
+	rt    http.RoundTripper
+}
 
-	return tokenResp.Token, nil
+func (t *jwtTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	req.Header.Set("Authorization", "Bearer "+t.token)
+	req.Header.Set("Accept", "application/vnd.github.v3+json")
+	req.Header.Set("User-Agent", "terraform-provider-kw-github")
+	return t.rt.RoundTrip(req)
 }