Stitches is a task runner for GRASS GIS, an alternative to running BASH and
Python scripts with Grass’s
- Session support: no need to start GRASS GIS before running any tasks.
- Caching: task state is tracked to skip tasks when possible to do so.
- Composability: tasks may be organised into pipelines and used as tasks.
- Pipelines may be called with custom variables and use Jinja2 in their definitions for more generic data processing.
- Custom tasks may be written as simple python functions.
Stitches works on Python 2.7 and Python 3.7 or later with GRASS GIS 7.4+. It is currently only tested on Linux (other platforms may follow).
$ pip install stitches-gis
$ firstname.lastname@example.org:davebrent/stitches.git $ cd stitches $ python setup.py install
Once stitches is installed, the
stitches command should become available in
Create a simple pipeline file
Save this file as
pipeline.toml (or any name you like).
Then run the pipeline with stitches in verbose mode
$ stitches --verbose pipeline.toml
This should print the following to the console
: Hello world Completed
Please see the examples folder for more advanced uses of pipelines.
Stitches. Usage: stitches [--gisdbase=<path>] [--location=<name>] [--mapset=<name>] [[--skip=<task>]... [--force] | --only=<task>] [--log=<path>] [--verbose] [--nocolor] [--vars=<vars>] <pipeline> Options: -h --help Show this screen. -v --verbose Show more output. --log=<path> Task log output path. --nocolor Disable colorized output. --gisdbase=<path> Initial GRASS GIS database directory. --location=<name> Initial GRASS location. --mapset=<name> Initial GRASS Mapset. --skip=<task> Comma-separated list of tasks to skip. --only=<task> Run a single task. --force Force all tasks to run. --vars=<vars> Initial pipeline variables.
Run a pipeline with custom variables
$ stitches --vars="foo='hello' bar='world'" pipeline.toml
Skip the 2nd and 4th tasks in a pipeline
$ stitches --skip=1,3 pipeline.toml
Although there is no hard restriction, it is expected that a pipeline be run multiple times (such as during development) so it is suggested that they be indempotent with respect to its inputs and outputs.
A pipeline may declare the GRASS GIS database, location and mapset that it should be run against, or these values may be passed in via the command line.
A task may consist of one of the following:
- One of the provided Built-in Tasks.
- Another pipeline.
- An importable python callable, in the form of
importable.module:function. The referenced function is called with the task definition’s
paramsfield as keyword arguments.
Resources may consist of GRASS GIS maps or regular files, their references should
follow the format
<type>/(<filepath> | <grassref>). Examples of valid
'file/foobar/baz.tif' # Relative path 'file//foobar/baz.tif' # Absolute path 'vector/map@gisdbase/location/mapset' # Map in specific database 'vector/map@location/mapset' # Map in a specific location 'vector/map@mapset' # Map in a specific mapset 'vector/map' # Map in this mapset
Its recommended to reference the resources used by a task to make the most of Caching.
The current state of resources used in a pipeline is tracked. If the following conditions are met the task will be skipped:
- The task is executed in the same region as its previous execution.
- The tasks
- No input files have been modified.
- Tasks that created any input maps were also skipped.
- Its output resources already exist.
A task will not be skipped if it is not possible for stitches to track the creation of any mapset used by the task.
The state of the initial pipeline’s execution is stored in a file called
stitches.state.json in the pipeline’s initial mapset. This may lead to
unexpected results when running different initial pipelines against the same
Toml configuration options¶
||str||Initial grass database directory.|
||str||Initial grass location.|
||str||Initial grass mapset (default:
||List[Task]||Tasks to run against the mapset.|
||str||Text to display when the task is run.|
||str||Path to a pipeline file.|
||str||Built-in task name (see Built-in Tasks) or a reference to an importable python function eg.
||List[str]||List of input resources.|
||List[str]||List of output resources.|
||List[str]||List of resources removed by the task.|
||bool||Option to always run the task/pipeline.|
||dict||Task/pipeline keyword arguments.|
taskmust be defined.
||str||Grass database directory (not implemented).|
||str||Grass location (not implemented).|
||str||Grass mapset (not implemented).|
||dict||Variables passed into the pipeline.|
- Switching database, location and mapset automatically, when calling another pipeline, is not yet implemented.
Run a GRASS GIS command.
Please refer to the relevant version of documentation for
grass.pygrass.modules.Modulefor more information.
- module (str) – GRASS GIS command name
- **kwargs – Keyword arguments passed to
Run an arbitrary shell command.
Keyword Arguments: cmd (list) – A sequence of program arguments