dotdrop/CONTRIBUTING.md

Contents

• Code base
• Config parsing
  • Lower layer
  • Higher layer
  • Precedence
  • Variable resolution
  • Rules
• Testing
  • Testing with unittest
  • Testing with bash scripts
• Documentation

Thanks for helping out!

Feature requests, bug reports, and PRs are always welcome!

This file provides a few pointers on how to contribute to dotdrop and where to find information. For any questions, feel free to open an issue.

For PRs adding new features, I'd be very thankful if you could add either a unittest for the added feature or a bash script test (see testing), thanks!

Code base

Dotdrop's code base is located in the dotdrop directory.

Here's an overview of the different files and their roles:

• action.py: represents the actions and transformations
• cfg_yaml.py: the lower level config parser (see lower layer)
• cfg_aggregator.py: the higher level config parser (see higher layer)
• comparator.py: the class handling the comparison for compare
• dictparser.py: abstract class for parsing dictionaries
• dotdrop.py: the entry point and where the different CLI commands are executed
• dotfile.py: represent a dotfile
• installer.py: the class handling the installation of dotfile for install
• jhelpers.py: list of methods available in templates with Jinja2
• linktypes.py: enum for the three types of linking (none, symlink, children)
• logger.py: the custom logger
• options.py: the class embedding all the different options across dotdrop
• profile.py: represents a profile
• settings.py: represents the config settings
• templategen.py: the Jinja2 templating class
• updater.py: the class handling the update of dotfiles for update
• utils.py: some useful methods used across the code base

Config parsing

The configuration file (YAML) is parsed using two layers:

• First in the lower layer in cfg_yaml.py
• Then in the higher layer in cfg_aggregator.py

Only the higher layer is accessible to other classes of dotdrop.

Lower layer

This is done in cfg_yaml.py.

The lower layer part only takes care of basic types and does the following:

• Normalize all config entries
  • Resolve paths (dotfiles src, dotpath, etc)
  • Refactor actions/transformations to a common format
  • Etc.
• Import any data from external files (configs, variables, etc)
• Apply variable substitutions
• Complete any data if needed (add the "profile" variable, etc)
• Execute intrepreted variables through the shell
• Write new entries (dotfile, profile) into the dictionary and save it to a file
• Fix any deprecated entries (link_by_default, etc)
• Clear empty entries

In the end, it builds a cleaned and normalized dictionary to be accessed by the higher layer.

Higher layer

This is done in cfg_aggregator.py.

The higher layer will transform the dictionary parsed by the lower layer into objects (profiles, dotfiles, actions, transformations, etc). The higher layer has no notion of inclusion (profile included, for example) or file importing (import actions etc.) or even interpreted variables (it only sees variables that have already been interpreted).

It does the following:

• Transform dictionaries into objects
• Patch lists of keys with their corresponding objects (For example, dotfile's actions)
• Provide getters for every dotdrop class that needs to access elements

Note that any changes to the YAML dictionary (adding a new profile or a new dotfile for example) won't be seen by the higher layer until the config is reloaded. Consider the dirty flag as a sign the file needs to be written and its representation in higher levels in not accurate anymore.

Precedence

• dynvariables > variables
• Profile (dyn)variables > any other (dyn)variables
• Profile (dyn)variables > profile's included (dyn)variables
• Imported variables/dynvariables > (dyn)variables

Variable resolution

How variables are resolved (through Jinja2's templating) in the config file.

• Resolve main config file variables
  • Merge variables and dynvariables (allowing cyclic references)
  • Recursively template merged variables and dynvariables
  • dynvariables are executed
  • Profile's variables and dynvariables are merged
• Resolve included entries (see below)
  • Paths and entries are templated (allows using something like include {{@@ os @@}}.variables.yaml)
• included entries are processed
  • dyn-/variables are all resolved in their own file

Potential included entries:

• Entry import_actions
• Entry import_configs
• Entry import_variables
• Profile's import
• Profile's include

Variables are then used to resolve different elements in the config file: see this.

Rules

• dynvariables are executed in their own config file
• Since variables and dynvariables are templated before the dynvariables are executed, this means that dynvariables can safely reference variables; however, variables referencing dynvariables will result in the not-executed value of the referenced dynvariables (see examples below).
• Profiles cannot include profiles defined above in the import tree
• Config files do not have access to variables defined above in the import tree
• Actions/transformations using variables are resolved at runtime (when the action/transformation is executed) and not when loading the config
• The same config file cannot be imported twice

This will result in dvar0 = "test" and var0 = "echo test" (not var0 = test):

variables:
  var0: "{{@@ dvar0 @@}}"
dynvariables:
  dvar0: "echo test"

This will result in dvar0 = "test" and var0 = "test":

variables:
  var0: "test"
dynvariables:
  dvar0: "echo {{@@ var0 @@}}"

Testing

Dotdrop is tested with the use of the tests.sh script.

• Test for PEP8 compliance with pycodestyle and pyflakes
• Run the unittest available in tests directory
• Run the bash script tests in tests-ng directory

Testing with unittest

All unittests are available in the tests directory and use Python's unittest.

The file helpers.py provides different helper methods for the tests.

Testing with bash scripts

The bash scripts are available in tests-ng directory. These test entire workflows by simulating the use of dotdrop from end to end for different use-cases (usually described in their filename or in the file header).

Each script starts with the same boilerplate code that you can paste at the start of your new test (see the head of the file down to # this is the test).

To run the tests on OSX, install following tools with homebrew

brew install coreutils gnu-sed

Documentation

Dotdrop documentation is available under https://dotdrop.readthedocs.io/.