Installing IBM Developer for z/OS on VS Code

IBM Z® Open Editor is an extension for VS Code. Before installation, ensure that you have installed and configured the prerequisites, most importantly a Java runtime as main parts of the extension are implemented in the Java programming language.

Prerequisites

Review the IBM Z Open Editor License Agreement and Third Party Notices before you download.

Prerequisites for the installation:

Visual Studio Code version 1.91.0 or later: IBM Z Open Editor is delivered as an extension to VS Code instead of a stand-alone editor, so you must install and configure VS Code first. We recommend always using the latest version of VS Code available. If you do not have VS Code installed we recommend using the Visual Studio Code for Java Installer provided by Microsoft, because it automatically downloads and installs a Java SDK together with VS Code. (You can skip the next bullet about Java dependency if you use this option.) For information about installation and configuration of VS Code, see its documentation.
Java SDK or JRE version 17 or later - 64 bit: The language servers included in this extension are implemented in Java. Therefore, you need to install and configure a 64-bit Java SDK or Runtime in order to start the extension successfully. We recommend to install VS Code for Java as described above, but if you already have VS Code or want to install Java yourself, then you can choose from the following options:
- We highly recommend using versions 17 or 21 of IBM's Semeru Runtime that can be downloaded here. IBM® Semeru Runtimes enable developers to build and deploy Java applications that starts quickly and delivers great performance - all while using less memory. We use it ourselves for development.
- Alternatively, you can use the LTS versions 17 or 21 of Oracle Java or the OpenJDK.
- Newer versions of Java should also work, but are not tested with Z Open Editor.
Various settings are provided to configure how the extension uses Java. See the Configuring Java section below for more details.
Zowe Explorer VS Code extension 3.0.0 or later and Zowe CLI 8.0.0 or later (optional): To make use of Zowe to open and edit files directly from z/OS® MVS™ or z/OS UNIX System Services, you need Zowe client software and host components configured. More information on setting up Zowe can be found at Setting up integrations to interact with z/OS. Once installed, you can access z/OS resources as documented in Interacting with z/OS.

Note: When you install IBM Z Open Editor from the VS Code Marketplace into your VS Code, the latest version of the Zowe Explorer VS Code extension is automatically co-installed as it is a mandatory prerequisite for running Z Open Editor.
(Optional) Git: To use the features that involve Git, you must install Git and have it available in your system path so that VS Code can display it. On Macs, Git comes out of the box. On Linux, you can install Git with your distribution's package manager. On Windows, you can get Git from https://git-scm.com.

Downloading IBM Developer for z/OS on VS Code

Download the client of IBM Developer for z/OS on VS Code from Mainframe DEV according to Procedure for downloading installation packages from Mainframe DEV. Extract the downloaded IBM_Developer_for_z/OS_on_VSCode.zip on your machine.

If you want to check code signing signatures for the downloaded binary files, refer to the following procedure. Install OpenSSL if you have not done so.

The IBM_Developer_for_z/OS_on_VSCode.zip you extracted above contains the .sig and .pem files that are used to verify the binary files.
Check the certificate validity.
1. To view the certificate details, issue the following command:
```
$ openssl x509 -text -in wazi-certificate.pem -noout
```
2. To view thhe public key details, issue the following command:
```
$ openssl rsa -noout -text -inform PEM -in wazi-public.pem -pubin
```
3. Compare the exponent of the public key and the certificate to see that the public key is indeed the one within the certificate. You can also use any other certificate viewer such as Mac OS Preview.
4. To check the validity of IBM public certificate, issue the following command:
```
$ openssl ocsp -no_nonce -issuer wazi-chain0.pem -cert wazi-certificate.pem -VAfile wazi-chain0.pem -text -url http://ocsp.digicert.com -respout ocsptest
```
  If the certificate is valid, the output is:
```
Response verify OK
```
Verify the downloaded binary files.

To verify the files by using the signature and public key files, issue the following command:
```
$ openssl dgst -sha256 -verify wazi-public.pem -signature ${binary-filename}.sig ${binary-filename}
```
For example, to verify zopeneditor-1.0.0.vsix, issue:
```
$ openssl dgst -sha256 -verify wazi-public.pem -signature zopeneditor-1.0.0.vsix.sig zopeneditor-1.0.0.vsix
```
If the binary is verified successfully, the output is:
```
Verified OK
```

Install IBM Z Open Editor

There are three ways to download and install IBM Z Open Editor. If you are planning to use or evaluate the non-warranty and unsupported version of IBM Z Open Editor then you can install it directly from the VS Code Marketplace or the Open VSX Registry. If you are an IBM Developer for z/OS Enterprise Edition or IBM Application Delivery Foundation for z/OS customer, or are entitled to technical support for Z Open Editor in any other way, we recommend you download from our Mainframe DEV Download site. This convenient zip file download includes code signing signature files and all related software components such as the IBM Z Open Debug VS Code extension, the IBM RSE API Plugin for Zowe CLI, and Zowe CLI.

Install IBM Z Open Editor from a VSIX file

If you have downloaded the Mainframe DEV Center's Download for VS Code, you can install it with the following steps in VS Code.

Unzip the downloaded zip file.
Open the README.txt file in a text editor and follow the (optional) steps described there to verify the individual files with the provided code signing signatures.
To install the zopeneditor-\<version\>.vsix file in VS Code, click the Extensions icon in VS Code's activity bar to open the Extensions view.
Click the ... icon in the Extensions view's upper-right corner to reveal a drop-down menu of more actions.
In the drop-down menu that appears, click Install from VSIX....
Use the file picker that pops up to navigate to and select the VSIX file you downloaded, and then click Install.
The extension should be installed from the VSIX file.

Install IBM Z Open Editor from the Open VSX Registry

If you already have or want to configure VS Code to use the alternative public or a private on-site Open VSX Registry, or if you are using a VS Code compatible editor such as VSCodium or Eclipse Theia that use it by default, then you can find and install IBM Z Open Editor and install it from there as well. See the Open VSX documentation for how to configure and use this registry instead.

Install IBM Z Open Editor from the VS Code marketplace

When the correct Java runtime is installed and configured, you can use either of the following ways to get versions of IBM Z Open Editor that are available in the VS Code Marketplace:

Start VS Code, open the Extensions view by clicking the Extensions icon on the activity bar, or by clicking the menu File > Preferences > Extensions, and search for IBM Z Open Editor.
Go to the VS Code Marketplace website that hosts IBM Z Open Editor.

Then, click the Install button and wait for the installation to complete.

Verify the installation of IBM Z Open Editor

To quickly test whether IBM Z Open Editor is installed correctly, you can open a COBOL, PL/I, HLASM, REXX, or JCL program file on your machine. If you do not have such files on your machine, you can clone the sample repository as described in the Exploring the sample files section and open its COBOL, PL/I, HLASM, REXX, or JCL program files. If you see syntax highlighting on COBOL, PL/I, HLASM, REXX, or JCL code, the extension is working correctly.

Configure Java

The IBM Z Open Editor Welcome page shows you if Java was found successfully. To open the Welcome page, press Ctrl+Shift+P (Windows) or Cmd+Shift+P (MacOS), and type IBM Z Open Editor: Welcome. Check the prerequisites table on the page, and click the Java section to expand.

The COBOL, PL/I, HLASM, REXX, and JCL language servers used by IBM Z Open Editor were implemented using the Java programming language. Therefore, a Java Runtime is required to be available through settings or the program path to start in VS Code. The IBM Z Open Editor extension uses VS Code Settings properties, which can be added to VS Code user settings, to configure which and how Java should be used. These settings allow you to select the specific installation of Java to pick, in case you have several installations, as well as set parameters such as how much memory you want the extension to use.

Select the Java installation to use

Before you start a language server, the language server clients in the IBM Z Open Editor VS Code extension try to look in different places to find a match Java installation. They look in the following places in this specific order and pick the first Java installation that is at least version 17 and 64-bit. If it finds a Java that fails the test against these criteria, it continues to search.

The zopeneditor.JAVA_HOME VS Code user setting.
The java.home VS Code user setting.
The JAVA_HOME environment variable.
The PATH defined for the environment in which Z Open Editor runs, that is, you default Windows or MacOS path.
A typical platform-specific location. For example, on MacOS, execute the /usr/libexec/java_home -V; on Windows, run the where java.exe commands to locate a valid Java installation.

As you can see, user settings always take precedence over the other options listed, which enables you to specify a different Java version for IBM Z Open Editor than the default on your computer in case you have installed multiple versions. If you used the recommended Visual Studio Code for Java Installer, the java.home user setting was set by this installer. Also note that the methods at the end of the list require a significant amount of time as they are executing programs on your system. To improve startup times you should consider user settings as they provide the best startup performance.

If Java cannot be located, check the VS Code Output view's Z Open Editor tab for any error and try to fix the problem by either setting the JAVA_HOME environment variable or creating an entry in your VS Code user settings.

To define a user setting, use the Preferences > Settings menu and either locate the setting in the graphical editor under IBM Z Open Editor or edit the setting JSON file directly by adding an entry as follows using an absolute path name to the Java installation directory.

On MacOS:

"zopeneditor.JAVA_HOME": "/Library/Java/JavaVirtualMachines/jdk17/Contents/Home"

On Windows:

"zopeneditor.JAVA_HOME": "C:\\Program Files\\Java\\jdk17"

Configure the Java memory allocation

By default, the language server client that starts the individual language servers for COBOL, PL/I, HLASM, or REXX allocates a maximum of 512 MB of memory for each. The language servers consume much less memory at startup, and then allocate and free memory when you parse programs. However, they might run out of memory when you parse very large program files and reach the predefined limit. To allow allocation of more memory, use the following VS Code setting to specify a new maximum value:

"zopeneditor.server.memoryAllocation": 640

Keep in mind that this value is for each language you use, so when using both COBOL and PL/I, you might end up with a consumption of double the amount specified. If you are working with smaller programs or your computer might not support such a large amount of memory, you can also try values smaller than 512 with this setting.

Using IBM Z Open Editor in cloud-based editors

Z Open Editor can be installed and used with various cloud or browser-based editing environments that utilize VS Code as the editor. See Overview to using Cloud and Browser-based platforms for some quickstart tutorials and configuration examples.