How to update job config files using the REST API and Java?

Article ID:226835367
2 minute readKnowledge base

Issue

I would like to be able to update job config files remotely using the Jenkins REST API and Java.

Resolution

Get current config:

import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Base64;

public class Main {

  private static final int BUFFER_SIZE = 4096;

  public static void main(String[] args) {
    try {
      URL url = new URL("https://localhost:8080/job/test/config.xml"); // Jenkins URL localhost:8080, job named 'test'
      String user = "developer"; // username
      String pass = "developer"; // password or API token
      String authStr = user + ":" + pass;
      String encoding = Base64.getEncoder().encodeToString(authStr.getBytes("utf-8"));

      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      connection.setDoOutput(true);
      connection.setRequestProperty("Authorization", "Basic " + encoding);

      Path testProjectConfigPath = Files.createTempFile("test", "config.xml"); // change to the path that makes sense in your case
      try (InputStream inputStream = connection.getInputStream();
           OutputStream outputStream = Files.newOutputStream(testProjectConfigPath)) {
        int bytesRead;
        byte[] buffer = new byte[BUFFER_SIZE];
        while ((bytesRead = inputStream.read(buffer)) != -1) {
          outputStream.write(buffer, 0, bytesRead);
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

Post updated config:

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Base64;

public class Main {

  private static final byte[] BUFFER = new byte[8192];

  public static void main(String[] args) {
    try {
      URL url = new URL("https://localhost:8080/job/test/config.xml"); // Jenkins URL localhost:8080, job named 'test'
      String user = "developer"; // username
      String pass = "developer"; // password or API token
      String authStr = user + ":" + pass;
      String encoding = Base64.getEncoder().encodeToString(authStr.getBytes("utf-8"));
      Path configPath = Paths.get("/path/to/config.xml") // A path to the modified project configuration file.

      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      connection.setReadTimeout(10000);
      connection.setConnectTimeout(15000);
      connection.setRequestMethod("POST");
      connection.setUseCaches(false);
      connection.setDoInput(true);
      connection.setDoOutput(true);
      connection.setRequestProperty("Authorization", "Basic " + encoding);

      try (InputStream inputStream = Files.newInputStream(configPath);
           DataOutputStream wr = new DataOutputStream(connection.getOutputStream())) {
        int c;
        while ((c = inputStream.read(BUFFER, 0, BUFFER.length)) > 0) {
          wr.write(BUFFER, 0, c);
        }
      }

      InputStream content = connection.getInputStream();
      BufferedReader in = new BufferedReader(new InputStreamReader(content));
      String line;
      while ((line = in.readLine()) != null) {
        System.out.println(line);
      }

    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

Obviously, replace:

  • developer:developer with your username:password

  • localhost:8080 with your Jenkins URL

  • test with your job name

See Remote Access API for more.

This article is part of our Knowledge Base and is provided for guidance-based purposes only. The solutions or workarounds described here are not officially supported by CloudBees and may not be applicable in all environments. Use at your own discretion, and test changes in a safe environment before applying them to production systems.