Set up a development environment manually¶
This document describes getting the source from watcher Git repository for development purposes.
To install Watcher from packaging, refer instead to Watcher User Documentation.
This document assumes you are using Ubuntu or Fedora, and that you have the following tools available on your system:
Python 2.7 and 3.5
msgfmt (part of the gettext package)
virtualenv and virtualenvwrapper
Reminder: If you’re successfully using a different platform, or a different version of the above, please document your configuration here!
Getting the latest code¶
Make a clone of the code from our Git repository:
$ git clone https://opendev.org/openstack/watcher.git
When that is complete, you can:
$ cd watcher
Watcher maintains two lists of dependencies:
The first is the list of dependencies needed for running Watcher, the second list includes dependencies used for active development and testing of Watcher itself.
However, your system may need additional dependencies that pip (and by extension, PyPi) cannot satisfy. These dependencies should be installed prior to using pip, and the installation method may vary depending on your platform.
$ sudo apt-get install python-dev libssl-dev libmysqlclient-dev libffi-dev
$ sudo dnf install redhat-rpm-config gcc python-devel libxml2-devel
$ sudo yum install gcc python-devel libxml2-devel libxslt-devel mariadb-devel
PyPi Packages and VirtualEnv¶
We recommend establishing a virtualenv to run Watcher within. virtualenv limits the Python environment to just what you’re installing as dependencies, useful to keep a clean environment for working on Watcher.
$ mkvirtualenv watcher $ git clone https://opendev.org/openstack/watcher.git # Use 'python setup.py' to link Watcher into Python's site-packages $ cd watcher && python setup.py install # Install the dependencies for running Watcher $ pip install -r ./requirements.txt # Install the dependencies for developing, testing, and running Watcher $ pip install -r ./test-requirements.txt
This will create a local virtual environment in the directory
The virtual environment can be disabled using the command:
You can re-activate this virtualenv for your current shell using:
$ workon watcher
Verifying Watcher is set up¶
Once set up, either directly or within a virtualenv, you should be able to invoke Python and import the libraries. If you’re using a virtualenv, don’t forget to activate it:
$ workon watcher
You should then be able to import watcher using Python without issue:
$ python -c "import watcher"
If you can import watcher without a traceback, you should be ready to develop.
Run Watcher tests¶
Build the Watcher documentation¶
You can easily build the HTML documentation from
doc/source files, by using
$ workon watcher (watcher) $ cd watcher (watcher) $ tox -edocs
The HTML files are available into
Configure the Watcher services¶
Watcher services require a configuration file. Use tox to generate a sample configuration file that can be used to get started:
$ tox -e genconfig $ cp etc/watcher.conf.sample etc/watcher.conf
Most of the default configuration should be enough to get you going, but you still need to configure the following sections:
[database]section to configure the Watcher database
[keystone_authtoken]section to configure the Identity service i.e. Keystone
[watcher_messaging]section to configure the OpenStack AMQP-based message bus
watcher_clients_authsection to configure Keystone client to access related OpenStack projects
So if you need some more details on how to configure one or more of these sections, please do have a look at Configuring Watcher before continuing.
Create Watcher SQL database¶
When initially getting set up, after you’ve configured which databases to use, you’re probably going to need to run the following to your database schema in place:
$ workon watcher (watcher) $ watcher-db-manage create_schema
Running Watcher services¶
To run the Watcher API service, use:
$ workon watcher (watcher) $ watcher-api
To run the Watcher Decision Engine service, use:
$ workon watcher (watcher) $ watcher-decision-engine
To run the Watcher Applier service, use:
$ workon watcher (watcher) $ watcher-applier
Default configuration of these services are available into
directory. See Configuring Watcher for details on how Watcher is
configured. By default, Watcher is configured with SQL backends.
Interact with Watcher¶
You can also interact with Watcher through its REST API. There is a Python Watcher client library python-watcherclient which interacts exclusively through the REST API, and which Watcher itself uses to provide its command-line interface.
There is also an Horizon plugin for Watcher watcher-dashboard which allows to interact with Watcher through a web-based interface.
Exercising the Watcher Services locally¶
If you would like to exercise the Watcher services in isolation within a local virtual environment, you can do this without starting any other OpenStack services. For example, this is useful for rapidly prototyping and debugging interactions over the RPC channel, testing database migrations, and so forth.
You will find in the watcher-tools project, Ansible playbooks and Docker template files to easily play with Watcher services within a minimal OpenStack isolated environment (Identity, Message Bus, SQL database, Horizon, …).