Announcing forth-keystoneclient

Over the past few weeks I’ve been working on a new client implementation for keystone. Python is a bit bloated for nimble CLIs like keystone, and so I went back to a language I used at my first job back in 1999, Forth. Forth is interpreted like python but it’s also very simple and memory efficient. And unlike python, forth can fit on a floppy disk. This allows this client to be installed onto satellites and other memory constrained environments. For embedded systems, forth also makes a great alternative to C. Now, onto the client.

Mastering Forth

Mastering Forth

As you probably know, forth is stack-based, and no real programmer likes someone else managing the stack for them. I’ve taken this paradigm into the client design. So let’s dive in. Below is an example usage so you can see how simple it is:

First we remember the definition of what user-role-list does. Python offers the “help” and “dir” for introspection, forth has ‘ and DUMP which work just as well. First let’s make sure user-role-list is defined:

' user-role-list  ok

Then let’s see what it’s doing:

' user-role-list 64 cells dump
7F0A31F7F300: D5 44 40 00  00 00 00 00 - 00 00 00 00  00 00 00 00  .D@.............
7F0A31F7F310: 25 46 40 00  00 00 00 00 - 20 DE F2 31  0A 7F 00 00  %F@..... ..1....
7F0A31F7F320: 88 46 40 00  00 00 00 00 - 99 99 99 99  99 99 99 99  .F@.............

As you can simply tell from the above, we need to pass in the tenant-id and user-id, so let’s make the call.

S" de4442c6e54a43459eaab97e26dc21bc2"  ok
S" 2ebadab9148d421287eee6d264f29736d"  ok
user-role-list 33  
| id | name | user_id | tenant_id |
| 006eaf0730e44756bc679038477d3bbd | Member | 2ebadab9148d421287eee6d264f29736d | de4442c6e54a43459eaab97e26dc21bc2 |
| 03e83b65036a4e0cbd7cff5bff858c76 | admin | 2ebadab9148d421287eee6d264f29736d | de4442c6e54a43459eaab97e26dc21bc2 |

I’ll be handing this out on floppy disks at the OpenStack conference in Atlanta if you’re interested, come find me and I’ll make you a copy.

Prepping for distribution at the conference

Prepping for distribution at the conference

A note on debugging, if you plan on installing this on satellites remember how the speed of light can interact with your token expiration timeout.

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