Zowe: What should I used on my client to talk to z/OS?

There are different ways of accessing the z/OS server.

• You can use a web server. You will need to configure the certificates.
• You can write your own program, for example in C or Java.
• cUrl is a very common tool. Handy for small tasks.
• HTTPie is an easy tool to generate one of commands. The output comes back nicely formatted, with colour. HTTPie is written in Python.
• Python has good support for TLS and working with back send-servers. You can capture the data in a dictionary to make it easy to process.
• You can use zowe Command Level Interface (CLI). This uses the best bits of all of the above.

Which is best?

The answer is the old phrase “horses for courses”.

If you want to do a one-of then the above tools are all very similar.

If you want to use multiple back ends, for example production and test, then you need to have code which selects the host, port, certificates, and applications within a z/OSMF or Zowe instance, then you will need to have code which handles this. Zowe CLI has this code built in.

I could write some basic code in about 100 lines of Python to do this – but why bother?

A Zowe developer’s view

I asked a developer what is good about zowe CLI.

The most common use case I see with Zowe CLI is for use in automation/Jenkins. It saves you the trouble of having to write code to handle the REST requests. It also supports the use of plug-ins for other products or services running on z/OS, like Endeavor, ChangeMan, Db2, CICS, etc. to do more than just download/upload files or submit jobs (e.g., you could also interact with a version control system, issue Db2 queries, deploy changes to a CICS region, and so on). 

Regarding output/data types, Zowe CLI commands can also provide json output (by specifying the `–response-format-json` or `–rfj` flag on commands), which is pretty easy to work with in bash scripts using something jq on Linux to parse the output and extract fields that you need.

For example

With –response-format-json

zowe zos-files list data-set ‘COLIN.Z*’ … –response-format-json

Generated

{
  "success": true,
  "exitCode": 0,
  "message": "",
  "stdout": "COLIN.ZCONNECT.BETA.ZFS\nCOLIN.ZCONNECT.BETA.ZFS.DATA\nCOLIN.ZFS\n...
  "stderr": "",
  "data": {
    "success": true,
    "commandResponse": null,
    "apiResponse": {
      "items": [
        {
          "dsname": "COLIN.ZCONNECT.BETA.ZFS"
        },
        {
          "dsname": "COLIN.ZCONNECT.BETA.ZFS.DATA"
        },
     ...
    "returnedRows": 44,
      "JSONversion": 1
    }
  }

Without –response-format-json

COLIN.ZCONNECT.BETA.ZFS
COLIN.ZCONNECT.BETA.ZFS.DATA
COLIN.ZFS
COLIN.ZFS.DATA
COLIN.ZFS.DSFS
COLIN.ZFS.DSFS.DATA
...

The first output is easier to post-process.

Some articles on Zowe CLI

• Better Mainframe Automation using Zowe CLI and Python
• Running Zowe CLI on Jenkins with Docker
• A first step for merging Mainframe into Enterprise DevOps with CA Endevor® and Zowe CLI