Opinionated saltstack formula dependency resolver

Note: Install libgit2 with libssh2 support before installing this package.

$ brew install libgit2 --with-libssh2

Salt shakers requires an initial config file containing the metadata for the local formula. eg,

formula: my_organisation/local-formula

dependencies:
- some_organisation/test1-formula
- another_organisation/testa-formula>=v1.0.0
- another_organisation/testb-formula<=v4.0.0
- another_organisation/testc-formula==v2.0.0

To generate and download a list of formula requirements, simply run

salt-shaker install

This will also save a list of the requirements and their versions, by default in 'formula-requirements.txt'

If this file exists, you can run

salt-shaker install-pinned-versions

to install the requirements with their versions pinned by the formula requirements file version.

You can also run a check to see what changes would be made to the formula-requirements file if an install were run.

salt-shaker check

This is useful to see if the dependency resolution chain has changed since versions were pinned.

Salt shakers requires an initial config file containing the metadata for the local formula. eg,

formula: my_organisation/local-formula

exports:
- local

dependencies:
- some_organisation/test1-formula
- another_organisation/testa-formula>=v1.0.0
- another_organisation/testb-formula<=v4.0.0
- another_organisation/testc-formula==v2.0.0

Here, the name of the formula is set to be 'local-formula', with an organisation name of 'my_organisation'. This formula will have dependencies on the described formula, based on the format

<organisation>/<formula-name>(constraint)

By default formula organisation/name-formula will be exposed to salt minions as name. So you can later refer to it in your sls files using:

include:
- name

In some cases you might want to overwrite the default export name or even expose multiple exports. In such case add to metadata.yml:

exports:
- name1
- name2

Make sure you have both subdirectories available in formula:

\
+ name1/
| + init.sls
|
+ name2/
| + init.sls
|
+ metadata.yml

And from now on your formula will supply both exports and you can refer to them with:

include:
- name1
- name2

The constraint is optional and can take the form ==, >= or <= followed by a version tag. Salt shaker will use these constraints and the constraints of any sub-dependencies found recursively on these dependencies, handling conflicts to try and resolve them all to a logically satisfiable single constraint.

• '==' Equality takes priority over all other constraints, current equalities override any new ones
• '>=' The highest greater than bound takes precedence over the lower
• '<=' least less-than bound takes precedence over the higher
• '>=, <=' Opposite contraints will throw an exception, although these may be resolvable in practice

Constraints specified in the metadata file are parsed first, then these are sequential processed, with the full dependency tree for that entry being parsed before moving on to the next metadata dependency entry.

Salt shaker consists of two main processes. Firstly, a metadata resolver that can parse config files and generate a set of formulas with resolved dependencies

This dependency list can then be parsed and resolved into actual tags and sha's on github, downloaded into a local directory, and the set of formula requirements and their versions stored in a local file. This local file can be used as the base of future updates, so that the remote formulas versions are in effect 'pinned'.

There are a few flags that can be passed to alter salt-shakers behaviour.

--enable-remote-check: This will force salt-shaker to contact the remote repository when using pinned versions, updating any shas that tags resolve to, meaning that if a tag was moved then the change would be picked up. With the default behaviour tags are assumed to be immutable

--simulate: No operation mode where the full command specified will be run, but no alterations will be made to any config files.

--root_dir: Specify the root directory for salt-shaker to work in

--verbose, --debug: Increase the level of logging output from salt-shaker

It's as simple as running this command:

python setup.py nosetests