python-matrix-runner 1.2.0

Description:

pythonmatrixrunner 1.2.0

Matrix Runner for Python
Allows easy top level command line interface generation for matrix configurations.

Install
Installation using pip:
pip install python-matrix-runner
The appearance of matrix runner can be configured by placing a copy of the
default.conf into the users Python site base directory (user global
configuration) or next to a build script (local configuration). Figuring out
the right locations is assisted by the following command:
$ python -m matrix_runner config -h

Preferences
The following preferences can be configured:

global
Global settings.

loglevel
The default log level, one of:
DEBUG, INFO, WARNING, ERROR, CRITICAL



colors
Settings for colorized log output.
Colors can be one of: black, red, green, yellow, blue, purple, cyan, white
Style prefix can be one of: bold_, thin_
Background color prefix: bg_

DEBUG
Debug level log output.

INFO
Info level log output.

WARNING
Warning level log output.

ERROR
Error level log output.

CRITICAL
Critical level log output.

config
Matrix configuration column.

action
Action column.

summary_config
Summary table matrix configuration column.

summary_success
Summary table success cell.

summary_unstable
Summary table unstable cell, i.e. failing test cases.

summary_skip
Summary table skip cell.

summary_fail
Summary table fail cell.

summary_error
Summary table error cell.







Example Usage
Writing the following to build.py:
from enum import Enum
from matrix_runner import main, matrix_axis, matrix_action, matrix_command, matrix_filter

@matrix_axis("alpha", "a", "A configuration axis")
class MyAlphaAxisValue(Enum):
Value1 = ('value1', 'v1')
Value2 = ('value2', 'v2')
Value3 = ('value3', 'v3')

@matrix_action
def dump(config):
"""Dump configuration to console"""
yield dump_config(config)

@matrix_command()
def dump_config(config):
return ["sh", "-c", f"echo '{config}'"]

if __name__ == "__main__":
main()
Can be executed as:
$ ./build.py --help
usage: build.py [-h] [--silent | --verbose | --debug] [--pairwise] [--slice <HERE>/<TOTAL>] [--extra-args EXTRA_ARGS]
[--alpha ALPHA] [--dump-args DUMP_ARGS] action [action ...]

positional arguments:
action Action(s) to run: dump

optional arguments:
-h, --help show this help message and exit
--silent Silent mode, only errors are shown.
--verbose Verbose log output.
--debug Debug log output.
--pairwise, -2 Reduce number of combinations using pairwise algorithm.
--slice <HERE>/<TOTAL>
Cut set of combinations into <TOTAL> number of slices and run ony <HERE>th one.
--extra-args EXTRA_ARGS
Extra arguments for all actions.
--alpha ALPHA, -a ALPHA
A configuration axis: value1|v1, value2|v2, value3|v3
--dump-args DUMP_ARGS
Extra arguments for dump action.

$ ./build.py -a v[23] dump
[value2](dump:dump_config) /usr/bin/sh -c echo 'Config(alpha=<MyAlphaAxisValue.Value2: ('value2', 'v2')>)'
[value2](dump:dump_config) (Hello, World): Config(alpha=<MyAlphaAxisValue.Value2: (value2, v2)>)
[value2](dump:dump_config) /usr/bin/sh succeeded with exit code 0
[value3](dump:dump_config) /usr/bin/sh -c echo 'Config(alpha=<MyAlphaAxisValue.Value3: ('value3', 'v3')>)'
[value3](dump:dump_config) Config(alpha=<MyAlphaAxisValue.Value3: (value3, v3)>)
[value3](dump:dump_config) /usr/bin/sh succeeded with exit code 0

Matrix Summary
==============

alpha dump
------- -------
value2 success
value3 success
Matrix Runner automatically generates a comprehensive command line help.
Giving at least one action the commands for all permutations of configured
matrix axes are automatically executed one by one. In this example the
execution is limited by a regex pattern v[23].


Detailed Usage
The Matrix Runner constructs what gets executed by defining these elements:

Axis
Action
Command
Filter


Axis
Axes build up the actual configuration matrix to be rolled out. Each degree
of freedom in ones set of configuration can be mapped to a single axis by
annotating an Enum with @matrix_axis:
@matrix_axis("alpha", abbrev="a", desc="A configuration axis")
class MyAlphaAxisValue(Enum):
Value1 = ('value1', 'v1')
Value2 = ('value2', 'v2')
Value3 = ('value3', 'v3')
This adds an axis named alpha to the current builds configuration matrix.
The optional argument abbrev can be used to specify a shortcut to be
used from the command line, i.e. --alpha or -a. And the optional
argument desc enriches the argument parser with a help string.
The values in such an Enum can either be plain strings or tuples of strings.
Tuples can be used to provide multiple string representations for a single
value. In the example one can provide Value2 on the command line as
--alpha value2 or just as -a v2. Alternatively axis values can be
selected by providing a fnmatch.fnmatch pattern, e.g. -a v[23]. Be aware
that such a pattern selects all values which have at least one matching string
representation in its tuple.
The overall configuration matrix is calculated by permuting all values from all
specified axes. In a typical scenario it easily happens that some combinations
are known to be inappropriate. These can be filtered by specifying Filter’s.

Note
Don’t use the keywords help or pairwise as axis names. Same
applies to abbreviations h and 2 for those keywords. These
are already used for static Command Line arguments.



Action
Actions are used to capture different workflow steps, such as compile and
run for unit tests. A step is simply defined by decorating a function
with @matrix_action:
@matrix_action
def dump(config: Config<, results: List[Result]><, extra_args: List[str] = None>):
"""Dump configuration to console"""
pre_process()
yield dump_config(config, 'Hello', 'World')
post_process(<results>)
The function itself needs to return a Generator generating a list of
Command’s. The function is called once in preparation for each matrix
configuration.
The config argument gives access to the selected _Config permutation. It
can be used to generate the commands depending on the actual configuration.
The optional results argument can be used to gain access to the list of
Command results gathered so far, e.g. for adding post-processing.
The optional extra_args named-argument can be used to receive a list additional
command line arguments provided via –extra-args or –<action>-args.
The function needs to yield Command’s, i.e. dump_config needs to be
an annotated command function. Pre and post processing code can be added
around.


Command
Commands are actual command lines to be executed while forwarding their
standard output and standard error streams. A command is defined by decorating
a function with @matrix_command:
@matrix_command()
def dump_config(*args, **kwargs):
return ["sh", "-c", f"echo '{args}: {kwargs}'"]
The decorator takes optional keyword arguments to fine control how the returned
command line should be executed through subprocess.Popen:


exit_code: Union[int, Iterable[int], Callable[[int], bool]] = 0
Specifies exit codes denoting successful execution of the command, this can
either be

a specific integer exit code, by default 0, or
a sequence of integer exit codes, e.g. a range, or
a function that returns True for successful exit codes.





needs_shell: bool = False
Set this to True if the command requires a shell environment.




encoding: str = 'utf-8'
Set this to another character encoding if the command’s output does not
use an UTF-8 compatible character set.




exclusive: bool = False
Some command are known to be prone to concurrency issues. Setting this to
True will block concurrent invocations of the command, e.g. when using
Matrix Runner concurrently on the same machine.




timeout: Optional[float] = None
Commands prone to hick-ups (i.e. getting stuck) can be automatically killed
when a specified time span has elapsed [in seconds].




retry: Optional[int] = 1
Commands prone to occasional failures can be automatically repeated.
The result will reflect the latest return code. The output from all
tries is captured.




rest_period: Optional[float] = None
Some commands are known to be prone to concurrency issues. Setting this to
a value larger than 0 adds a rest period (i.e. time.sleep) before the
command actually gets executed.




test_report: Optional[ReportFilter] = None
By default the result of a command only depends on the exit_code. The
commands output is captured but not processed by Matrix Runner. By
specifying a “recipe” how to evaluate results the output can be post
processed into a detailed Report.




The actual command function can take arbitrary arguments which can be provided
during the enclosing Action. All arguments bound to a Command instance can
be inspected by reading the according object attribute, e.g.:
cmd = dump_config(*args, **kwargs) # Retrieve the Command object with bound arguments
print(cmd.args, cmd.kwargs) # Inspect the Command object's bound arguments

Command Result
For each single invocation of a Command the entire output is captured in a
CommandResult object. These objects can be used to inspect the details
of the execution using the following properties:


command: Command
A back-reference to the executed Command with bound arguments.




cmdline: List
The actual command line returned from the command function.




exit_status: Optional[Union[int, TimeoutError]]
The exit status returned by the command, or a TimeoutError exception if
occurred. A None indicates the command has run to completion, yet.




success: bool
Indicator for an overall successful execution. This value is calculated
from the actual exit_status and the expected Command’s exit_code.




output: StringIO
The captured stdout and stderr from the execution.




test_report: Optional[ReportFilter.Result]
The generated Report Result from applying the Command’s test_report.




start_time: float
The Unix Epoch the command was launched retrieved from time.time().




end_time: float
The Unix Epoch the command was finished time.time().




start_perf_counter: float
The value retrieved from time.perf_counter() before running the command.




end_perf_counter: float
The value retrieved from time.perf_counter() after running the command.







Report
A report can capture and post process the output of a command after execution.
This can be used to gather a test report from the commands standard output
into a standardized format. Though, this feature is not limit to test reports.
In order to attach report generation to a Command assign a pipe chain of
report generators to test_report. The available report generators are:


ConsoleReport()
Captures the console output of the command.




CropReport(first: AnyStr, last: AnyStr)
Crops a section out of the input. All lines between first and last
(inclusive) are kept, everything else is dropped.




TransformReport(xslt)
Applies the provided XSLT script to the input.




JUnitReport(title)
Treats the input as JUnit XML and provides a detailed summary. Set
title to a static string or a function
lambda(title: str <, result: CommandResult]>) -> str
to update the test suite names.




Report generators can be chained in pipe like manner:
ConsoleReport() |
CropReport("<report>", "</report>") |
TransformReport("tojunit.xsl") |
JUnitReport(title = lambda title, report: title)
This chain

Captures the console output of the command.
Crops all content between <report> and </report>, inclusive.
Transforms the custom XML to JUnit.
Considers the JUnit results for summary.

The Report Result is appended to the Command’s result test_report
property to be accessible, e.g. in Action functions.
The report can
be written to a file using its write(file: AnyStr) function.

Report Result
The ReportFilter.Result gives access to the final output of a Report
filter chain applied to a specific Command result. The following properties
and functions can be used to access the report:


stream -> StringIO
Direct access to the text stream.




getvalue() -> str
Final string output.




write(file: AnyStr)
Write the output into a file.




The mixin ReportFilter.Summary adds a detailed summary output in addition
to the default passed or failed one:


summary -> Tuple[int, int] returns a tuple of passed and executed
test cases.






Custom Reports
Custom report generators can be added by subclassing ReportFilter
overwriting its inner class ReportFilter.Result and giving a custom
stream -> StringIO property. The preceding generator can be accessed
through _other property. In case of an error while processing the report a
RuntimeError should be raised:
class CustomReport(ReportFilter):
class Result(ReportFilter.Result):
@property
def stream(self) -> StringIO:
if not self._stream:
try:
self._stream = StringIO()
input = self._other.stream
args = self._report.args
output = input # add some modification
self._stream.write(output)
except SomeException as e:
self._stream = e
if isinstance(self._stream, Exception):
raise RuntimeError from self._stream
else:
return self._stream

def __init__(self, *args):
super(CustomReport, self).__init__()
self.args = args
Additional report formats can be supported by mixing in ReportFilter.Summary
and providing a custom summary -> Tuple[int, int] property. The summary
shall return a tuple with numbers test cases (passed, executed):
class CustomSummary(ReportFilter):
class Result(ReportFilter.Result, ReportFilter.Summary):
@property
def summary(self) -> Tuple[int, int]:
passed = ... # calculate passed test cases
executed = ... # calculate executed test cases
return passed, executed



Filter
A filter can be used to remove inappropriate Config’s from the configuration
matrix. This is achieved by defining a function annotated with
@matrix_filter returning True for configuration to be dropped:
@matrix_filter
def filter(config):
return config.alpha.match('value3')


Config
A single matrix configuration with specific values for each matrix axis is
denoted by an Config object. The Config object contains a property
for each axis containing the value.
In order to check if an axis value matches a condition one can use the
match function providing a fnmatch.fnmatch pattern.


Command Line
Running one or more configurations from the command line using Matrix Runner is
trivial. The generated interface looks like this:
$ ./build.py --help
usage: build.py [-h] [--silent | --verbose | --debug] [--pairwise] [--slice <HERE>/<TOTAL>]
[--extra-args EXTRA_ARGS] [[--<axis> <AXIS>] ...]
[--<action>-args <ACTION>_ARGS] action [action ...]
The positional argument action can be one or multiple define Action’s to
be executed in the given order, e.g. either build and run separately or
both in a sequence.
The optional arguments are a combination of static ones used to parametrize
Matrix Runner itself and dynamic ones generated from the defined Axis:

-h, --help shows the help message
--silent Silent mode, only errors are shown.
--verbose Verbose log output.
--debug Debug log output.
-2, --pairwise reduces number of combinations using pairwise
algorithm. This enables combinatorial all-pairs testing to reduce the
overall number of configuration in logarithmic manner while retaining a high
probability of detecting issues.
--slice <HERE>/<TOTAL> cuts the set of combinations into TOTAL number
of slices and executes only the HERE’th one. This can be used to run the
overall set of combinations in parallel. Slicing is applied after
--pairwise reduction.
--extra-args EXTRA_ARGS can be used to provide custom arguments passed
on to all action functions taking an extra_args` named-argument.
-<a> <AXIS>, --<axis> <AXIS> reduce number of combinations to
selected AXIS values for axis Axis values can be given as one of
their string representations or an fnmatch.fnmatch pattern matching at
least one of these. In case of pattern matching all matching values are
selected. This argument can be given multiple time which adds the values in a
cumulative way.
--<action>-args <ACTION>_ARGS can be used to provide custom arguments passed
specifically to the <action> functions taking an extra_args` named-argument.

The console output has two parts. While executing the actions the output from
the associated commands is forwarded like this:
[<AXIS>](<ACTION>) <pre processing log>
[<AXIS>](<ACTION>:<COMMAND>) <command line>
[<AXIS>](<ACTION>:<COMMAND>) <stdout/stderr from command>
[<AXIS>](<ACTION>) <post processing log>
Each line of output is prefixed with a [<AXIS>] per axis giving the
matrix configuration values the output belongs to. Followed by a
(<ACTION>:<COMMAND>) tag denoting the action and command currently
executed. On a color terminal there is a clear distinction between stdout
(green) and stderr (red) output. Intermediate warning messages from Python
are colored as yellow.
After all actions have been executed for all selected configurations a
comprehensive summary is displayed like this:
Matrix Summary
==============

<axis> <ACTION>
------- -------
<AXIS> success
<AXIS> FAILED
<AXIS> (skip)
... ...
The Matrix Summary gives a table with a column per axis and action. Each line
denotes all actions result for a specific configuration:

success (green) denotes all commands have been executed successfully (i.e. with expected exit codes)
FAILED (red) denotes a command has returned a failure exit code and execution got stalled

(skip) (yellow) denotes that this action has not been performed for that configuration.
Skipping configuration happens due to Filter’s.





Note
By default Matrix Runner scripts are expected to be run from their
local directory. Calling a script from anywhere else will create a
warning and the execution is likely to fail.




Utilities
Inspector
The command line utility matrix-runner-inspect can be used to inspect a
Matrix Runner build:
$ matrix-runner-inspect -h
usage: matrix-runner-inspect [-h] script
It takes only a single positional argument denoting the script to be inspected,
for example:
$ matrix-runner-inspect -- example.py
{
"axes": {
"alpha": {"abbrev": "a", "values": ["value1", "value2", "value3"],
"desc": "A configuration axis"}
},
"matrix": [{"alpha": "value1"}, {"alpha": "value2"}, {"alpha": "value3"}]
}
The output gives the axes definition and the actual configuration matrix. The
script take all the usual axis arguments as shown above. These can be used to
reduce the matrix reported by inspect:
$ matrix-runner-inspect -- demo/example.py -a v[23]
{
"axes": {"alpha": {"abbrev": "a", "values": ["value1", "value2", "value3"],
"desc": "A configuration axis"}},
"matrix": [{"alpha": "value2"}, {"alpha": "value3"}]
}