Long Refactoring: First New Unit Test

The heart of the code is the call to solve a single puzzle; the function tree_to_solution_string. We want to write a test that runs just this function. Getting there is not so easy.

This method is buried deep within the class SudokuSolver. But creating one of these essentially runs the entire code. In fact, we can redo our original test to run the code as a python call as opposed to a subprocess call. Lets’ start with that.

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Long Refactoring: Call a Unit Test

Our test takes 5 seconds to run. That is not horrible, but it does not bode well for when we write more tests. We don’t want to explode that number, and we want to be able to write more focused test. I’m going to do some project setup that will enable us to do more development, including fine grained unit tests.

I’m going to start by using tox.

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Running Ironic Standalone on RHEL

This is only going to work if you have access to the OpenStack code. If you are not an OpenStack customer, you are going to need an evaluation entitlement. That is beyond the scope of this article.

For me, I had to enable the repo openstack-16-for-rhel-8-x86_64-rpms. With that enabled I was able to install via yum:

yum install openstack-ironic-api mariadb-server python3-openstackclient python3-ironicclient openstack-ironic-conductor

Set up Maria DB

systemctl enable mariadb 
Created symlink /etc/systemd/system/mysql.service → /usr/lib/systemd/system/mariadb.service.
Created symlink /etc/systemd/system/mysqld.service → /usr/lib/systemd/system/mariadb.service.
Created symlink /etc/systemd/system/multi-user.target.wants/mariadb.service → /usr/lib/systemd/system/mariadb.service.
[root@nuzleaf ~]# systemctl start mariadb 
mysql -u root 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 8
Server version: 10.3.17-MariaDB MariaDB Server
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> create database ironic;
Query OK, 1 row affected (0.001 sec)
MariaDB [(none)]> CREATE USER 'ironic'@'localhost' IDENTIFIED BY 'ironic';
Query OK, 0 rows affected (0.001 sec)
MariaDB [(none)]> GRANT ALL PRIVILEGES ON ironic.* TO 'ironic'@'localhost';
Query OK, 0 rows affected (0.001 sec)
MariaDB [(none)]> \q

Make sure I can log in as the ironic user

mysql ironic -u ironic -p

Back up the config file:

cp /etc/ironic/ironic.conf /etc/ironic/ironic.conf.orig

I’ll use these values:

auth_strategy = noauth
enabled_hardware_types = ipmi
enabled_power_interfaces = ipmitool
rpc_transport = json-rpc

Now let me see if I can sync the database:

INFO  [alembic.runtime.migration] Context impl MySQLImpl.
INFO  [alembic.runtime.migration] Will assume non-transactional DDL.
INFO  [alembic.runtime.migration] Running upgrade  -> 2581ebaf0cb2, initial migration
INFO  [alembic.runtime.migration] Running upgrade 2581ebaf0cb2 -> 21b331f883ef, Add provision_updated_at
INFO  [alembic.runtime.migration] Running upgrade 28c44432c9c3 -> 2aac7e0872f6, Create deploy_templates and deploy_template_steps tables.
INFO  [alembic.runtime.migration] Running upgrade 2aac7e0872f6 -> 1e15e7122cc9, add extra column to deploy_templates

Seemed to work. Let’s start conductor:

systemctl status openstack-ironic-conductor
# systemctl status openstack-ironic-conductor
● openstack-ironic-conductor.service - OpenStack Ironic Conductor service
   Loaded: loaded (/usr/lib/systemd/system/openstack-ironic-conductor.service; disabled; vendor preset: disabled)
   Active: active (running) since Thu 2020-10-15 17:11:36 EDT; 1s ago
 Main PID: 491085 (ironic-conducto)
    Tasks: 1 (limit: 99656)
   Memory: 40.0M
   CGroup: /system.slice/openstack-ironic-conductor.service
           └─491085 /usr/bin/python3 /usr/bin/ironic-conductor
Oct 15 17:11:36 nuzleaf.home.younglogic.net systemd[1]: Started OpenStack Ironic Conductor service.

So far so good.

The API server is going to be an interesting piece. For a first run, I’ll try the command line version I ran on the upstream. However, my longer term approach will be to run it as a wsgi App behind the Apache server that is already running on this host.

Run the API server in one terminal


and open up a second one to try to hit it with curl.

$ curl
{"name": "OpenStack Ironic API", "description": "Ironic is an OpenStack project which aims to provision baremetal machines.", "versions": [{"id": "v1", "links": [{"href": "", "rel": "self"}], "status": "CURRENT", "version": "1.58", "min_version": "1.1"}], "default_version": {"id": "v1", "links": [{"href": "", "rel": "self"}], "status": "CURRENT", "version": "1.58", "min_version": "1.1"}}

Excellent. let’s try the command line. The python3-ironicclient RPM does not ship the baremetal executable, but using the openstack common client, we can see all of the baremetal sub-commands. To list the drivers and the nodes, we can use the following.

openstack baremetal driver list
| Supported driver(s) | Active host(s)              |
| ipmi                | nuzleaf.home.younglogic.net |
$ openstack baremetal node list

Edit: Next up was going to be configuring Apache to run the Ironic API as a WSGI App, but I decided to use the systemd files to enable and run Ironic for the time being. Here’s all the commands together.

systemctl start mariadb 
systemctl start openstack-ironic-conductor
systemctl start openstack-ironic-api
systemctl enable mariadb 
systemctl enable openstack-ironic-conductor
systemctl enable openstack-ironic-api

Edit 2: Seems I am having trouble connecting. I’m back to running the API from the command line. More to come.

Introduction to Ironic

“I can do any thing. I can’t do everything.”

The sheer number of projects and problem domains covered by OpenStack was overwhelming. I never learned several of the other projects under the big tent. One project that is getting relevant to my day job is Ironic, the bare metal provisioning service. Here are my notes from spelunking the code.

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Recovering Audio off an Old Tape Using Audacity

One of my fiorends wrote a bunch of music back in high school. The only remainig recordings are on a casette tape that he produced. Time has not been kind to the recordings, but they are audible…barely. He has a device that produces MP3s from the tape. My job has been to try and get them so that we can understand them well enough to recover the original songs.

I have the combined recording on a single MP3. I’ve gone through and noted the times where each song starts and stops. I am going to go through the steps I’ve been using to go from that single long MP3 to an individual recording.

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