crankshaft/CONTRIBUTING.md

# Development process

Please read the Working Process/Quickstart Guide in [README.md](https://github.com/CartoDB/crankshaft/blob/master/README.md) first.

For any modification of crankshaft, such as adding new features,
refactoring or bug-fixing, topic branch must be created out of the `develop`
branch and be used for the development process.

Modifications are done inside `src/pg/sql` and `src/py/crankshaft`.

Take into account:

*  Tests must be added for any new functionality
   (inside `src/pg/test`, `src/py/crankshaft/test`) as well as to
   detect any bugs that are being fixed.
*  Add or modify the corresponding documentation files in the `doc` folder.
   Since we expect to have highly technical functions here, an extense
   background explanation would be of great help to users of this extension.
*  Convention: snake case(i.e. `snake_case` and not `CamelCase`)
   shall be used for all function names.
   Prefix function names intended for public use with `cdb_`
   and private functions (to be used only internally inside
   the extension)  with `_cdb_`.

Once the code is ready to be tested, update the local development installation
with `sudo make install`.
This will update the 'dev' version of the extension in `src/pg/` and
make it available to PostgreSQL.
It will also install the python package (crankshaft) in a virtual
environment `env/dev`.

The version number of the Python package, defined in
`src/pg/crankshaft/setup.py` will be overridden when
the package is released and always match the extension version number,
but for development it shall be kept as '0.0.0'.

Run the tests with `make test`.

To use the python extension for custom tests, activate the virtual
environment with:

```
source envs/dev/bin/activate
```

Update extension in a working database with:

* `ALTER EXTENSION crankshaft UPDATE TO 'current';`
  `ALTER EXTENSION crankshaft UPDATE TO 'dev';`

Note: we keep the current development version install as 'dev' always;
we update through the 'current' alias to allow changing the extension
contents but not the version identifier. This will fail if the
changes involve incompatible function changes such as a different
return type; in that case the offending function (or the whole extension)
should be dropped manually before the update.

If the extension has not previously been installed in a database,
it can be installed directly with:

* `CREATE EXTENSION IF NOT EXISTS plpythonu;`
  `CREATE EXTENSION IF NOT EXISTS postgis;`
  `CREATE EXTENSION crankshaft WITH VERSION 'dev';`

Note: the development extension uses the development python virtual
environment automatically.

Before proceeding to the release process peer code reviewing of the code is
a must.

Once the feature or bugfix is completed and all the tests are passing
a Pull-Request shall be created on the topic branch, reviewed by a peer
and then merged back into the `develop` branch when all CI tests pass.

When the changes in the `develop` branch are to be released in a new
version of the extension, a PR must be created on the `develop` branch.

The release manage will take hold of the PR at this moment to proceed
to the release process for a new revision of the extension.

## Relevant development tasks available in the Makefile

```
* `make help` show a short description of the available targets

* `sudo make install` will generate the extension scripts for the development
  version ('dev'/'current') and install the python package into the
  development virtual environment `envs/dev`.
  Intended for use by developers.

* `make test` will run the tests for the installed development extension.
  Intended for use by developers.
```