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Install the Java agent with automatic updates on Linux

Some users like to automatically update their Contrast Java agent software to the latest version. Linux users can schedule Java agent updates from Maven Central using common Linux tools cron and curl.

Here's how to configure a scheduled Java agent update job on an Ubuntu 18.04 Linux host:


Use your preferred editor to create a file with the following contents. The examples provided use tee to create the file.

  1. If you want to perform each step as you follow along with this guide, you can use Vagrant and VirtualBox to create a new Ubuntu 18.04 virtual machine:

    vagrant init ubuntu/bionic64
    vagrant up
    vagrant ssh
  2. Create a shared directory for Contrast software:

    sudo mkdir -p /opt/contrast
  3. Create a script for installing the latest Java agent in the /etc/cron.daily directory. Scripts in this directory execute once daily; as a result, the host updates the latest Java agent each day.

  4. Use tee to create this script. Press CTRL+D when you've finished typing all the lines:

    $ sudo tee -a /etc/cron.daily/install-latest-contrast-agent > /dev/null
    #!/bin/bash -u
    curl --fail --silent --location "" -o /tmp/$CONTRAST_FILE_NAME
    if [ $? -ne 0 ]; then
        echo "Failed to download Contrast Java agent" >&2
        exit 1
  5. Set the execute bit on the new script file:

    sudo chmod +x /etc/cron.daily/install-latest-contrast-agent
  6. To test the script, execute it and then verify that the file exists using stat:

    $ sudo /etc/cron.daily/install-latest-contrast-agent
    $ stat /opt/contrast/contrast-agent.jar
    stat /opt/contrast/contrast-agent.jar
      File: /opt/contrast/contrast-agent.jar
      Size: 10568283        Blocks: 20648      IO Block: 4096   regular file
    Device: 801h/2049d      Inode: 256034      Links: 1
    Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
    Access: 2019-04-11 02:02:01.265775928 +0000
    Modify: 2019-04-11 02:24:47.849796936 +0000
    Change: 2019-04-11 02:24:47.849796936 +0000
     Birth: -
  7. The Contrast agent requires some configuration to communicate with Contrast. You can find agent key information here.

  8. When Contrast is installed on a Linux host, users typically want Contrast-enabled web applications on the host to share basic configuration parameters, such as the ones required to connect to Contrast. By convention, Contrast look for configuration in a YAML file at path /etc/contrast/java/contrast_security.yaml on Linux hosts.

  9. Create the /etc/contrast/java directory:

    sudo mkdir -p /etc/contrast/java
  10. Use tee to create the configuration file. Replace <contrast_url>, <your_api_key>, <agent_user_name> and <agent_user_service_key> with the values you obtained from Contrast in the previous step:

    $ sudo tee -a /etc/contrast/java/contrast_security.yaml > /dev/null
      url: <contrast_url>
      api_key: <your_api_key>
      user_name: <agent_user_name>
      service_key: <agent_user_service_key>
  11. Press CTRL+D when you've finished typing all the lines.

  12. Run a diagnostic test to verify that Contrast is installed and properly configured. The host must have Java installed to execute the diagnostic test:

    sudo apt install --yes openjdk-11-jre-headless
  13. Finally, execute the Java agent's diagnostic test to verify that the agent is installed correctly and can communicate with Contrast using the configuration parameters from /etc/contrast/java/contrast_security.yaml:

    $ java -jar /opt/contrast/contrast-agent.jar diagnostic
    *** Contrast Agent (version 3.6.3-SNAPSHOT)
    [!] Attempting to connect to the Contrast TeamServer at (No proxy).
    [!] Attempting to resolve domain:
            Resolved domain to IP Address
    [+] Client successfully resolved the DNS of the Contrast TeamServer. No proxy needed.
    [!] Issuing HTTP request to Contrast...
            Executing request...
            Reading response [200]
            Response size = 4209
            Snippet: <!doctype html> <!--[if gt IE 8]><!--> <html class="no-js" i
    [+] Client can connect directly to the Contrast TeamServer. No proxy needed.