Package: pyaml
PyYAML-based python module to produce a bit more pretty and human-readable YAML-serialized data.This module is for serialization only, seeruamel.yamlmodule for literate
YAML parsing (keeping track of comments, spacing, line/column numbers of values, etc).(side-note: to dump stuff parsed by ruamel.yaml with this module, use onlyYAML(typ='safe')there)It’s a small module, and for projects that only need part of its functionality,
I’d recommend copy-pasting that in, instead of adding janky dependency.ContentsWarningWhat this module does and whyFeatures and TricksInstallationRepository URLs:https://github.com/mk-fg/pretty-yamlhttps://codeberg.org/mk-fg/pretty-yamlhttps://fraggod.net/code/git/pretty-yamlWarningPrime goal of this module is to produce human-readable output that can be
easily diff’ed, manipulated and re-used, but maybe with occasional issues.So please do not rely on the thing to produce output that can always be
deserialized exactly to what was exported, at least - use PyYAML directly
for that (but maybe with options from the next section).What this module does and whyYAML is generally nice and easy format to readifit was written by humans.PyYAML can a do fairly decent job of making stuff readable, and the best
combination of parameters for such output that I’ve seen so far is probably this one:>>> m = [123, 45.67, {1: None, 2: False}, 'some text']
>>> data = dict(a='asldnsa\nasldpáknsa\n', b='whatever text', ma=m, mb=m)
>>> yaml.safe_dump( data, sys.stdout,
  width=100, allow_unicode=True, default_flow_style=False )
a: 'asldnsa

  asldpáknsa

  '
b: whatever text
ma: &id001
- 123
- 45.67
- 1: null
  2: false
- some text
mb: *id001pyaml (this module) tries to improve on that a bit, with the following tweaks:Most human-friendly representation options in PyYAML (that I know of)
are used as defaults - unicode, flow-style, width=100 (old default is 80).Dump “null” values as empty values, if possible, which have the same meaning
but reduce visual clutter and are easier to edit.Dicts, sets, OrderedDicts, defaultdicts, namedtuples, enums, dataclasses, etc
are represented as their safe YAML-compatible base (like int, list or mapping),
with mappings key-sorted by default for more diff-friendly output.Use shorter and simplier yes/no for booleans.List items get indented, as they should be.Attempt is made to pick more readable string representation styles, depending
on the value, e.g.:>>> yaml.safe_dump(cert, sys.stdout)
cert: '-----BEGIN CERTIFICATE-----

  MIIH3jCCBcagAwIBAgIJAJi7AjQ4Z87OMA0GCSqGSIb3DQEBCwUAMIHBMRcwFQYD

  VQQKFA52YWxlcm9uLm5vX2lzcDEeMBwGA1UECxMVQ2VydGlmaWNhdGUgQXV0aG9y
...

>>> pyaml.p(cert):
cert: |
  -----BEGIN CERTIFICATE-----
  MIIH3jCCBcagAwIBAgIJAJi7AjQ4Z87OMA0GCSqGSIb3DQEBCwUAMIHBMRcwFQYD
  VQQKFA52YWxlcm9uLm5vX2lzcDEeMBwGA1UECxMVQ2VydGlmaWNhdGUgQXV0aG9y
...“force_embed” option (default=yes) to avoid having &id stuff scattered all
over the output. Might be more useful to disable it in some specific cases though.“&idXYZ” anchors, when needed, get labels from the keys they get attached to,
not just meaningless enumerators, e.g. “&users_-_admin” instead.“string_val_style” option to only apply to strings that are values, not keys,
i.e:>>> pyaml.p(data, string_val_style='"')
key: "value\nasldpáknsa\n"
>>> yaml.safe_dump(data, sys.stdout, allow_unicode=True, default_style='"')
"key": "value\nasldpáknsa\n"Add vertical spacing (empty lines) between keys on different depths,
to separate long YAML sections in the output visually, make it more seekable.Discard end-of-document “…” indicators for simple values.Result for the (rather meaningless) example above:>>> pyaml.p(data, force_embed=False, vspacing=dict(split_lines=10))

a: |
  asldnsa
  asldpáknsa

b: whatever text

ma: &ma
  - 123
  - 45.67
  - 1:
    2: no
  - some text

mb: *ma(force_embed=False enabled deduplication with&maanchor,
vspacing is adjusted to split even this tiny output)Extended example:>>> pyaml.dump(data, vspacing=dict(split_lines=10))

destination:

  encoding:
    xz:
      enabled: yes
      min_size: 5120
      options:
      path_filter:
        - \.(gz|bz2|t[gb]z2?|xz|lzma|7z|zip|rar)$
        - \.(rpm|deb|iso)$
        - \.(jpe?g|gif|png|mov|avi|ogg|mkv|webm|mp[34g]|flv|flac|ape|pdf|djvu)$
        - \.(sqlite3?|fossil|fsl)$
        - \.git/objects/[0-9a-f]+/[0-9a-f]+$

  result:
    append_to_file:
    append_to_lafs_dir:
    print_to_stdout: yes

  url: http://localhost:3456/uri

filter:
  - /(CVS|RCS|SCCS|_darcs|\{arch\})/$
  - /\.(git|hg|bzr|svn|cvs)(/|ignore|attributes|tags)?$
  - /=(RELEASE-ID|meta-update|update)$

http:
  ca_certs_files: /etc/ssl/certs/ca-certificates.crt
  debug_requests: no
  request_pool_options:
    cachedConnectionTimeout: 600
    maxPersistentPerHost: 10
    retryAutomatically: yes

logging:

  formatters:
    basic:
      datefmt: '%Y-%m-%d %H:%M:%S'
      format: '%(asctime)s :: %(name)s :: %(levelname)s: %(message)s'

  handlers:
    console:
      class: logging.StreamHandler
      formatter: basic
      level: custom
      stream: ext://sys.stderr

  loggers:
    twisted:
      handlers:
        - console
      level: 0

  root:
    handlers:
      - console
    level: customNote that unless there are many moderately wide and deep trees of data,
which are expected to be read and edited by people, it might be preferrable
to directly use PyYAML regardless, as it won’t introduce another
(rather pointless in that case) dependency and a point of failure.Features and TricksPretty-print any yaml or json (yaml subset) file from the shell:% python -m pyaml /path/to/some/file.yaml
% pyaml < myfile.yml
% curl -s https://www.githubstatus.com/api/v2/summary.json | pyamlpipx install pyamlcan be a good way to only install “pyaml” command-line script.Process and replace json/yaml file in-place:% python -m pyaml -r mydata.ymlEasier “debug printf” for more complex data (all funcs below are aliases to same thing):pyaml.p(stuff)
pyaml.pprint(my_data)
pyaml.pprint('----- HOW DOES THAT BREAKS!?!?', input_data, some_var, more_stuff)
pyaml.print(data, file=sys.stderr) # needs "from __future__ import print_function"Force all string values to a certain style (see info on these inPyYAML docs):pyaml.dump(many_weird_strings, string_val_style='|')
pyaml.dump(multiline_words, string_val_style='>')
pyaml.dump(no_want_quotes, string_val_style='plain')Usingpyaml.add_representer()(note *p*yaml) as suggested inthis SO thread(orgithub-issue-7) should also work.See also thisamazing reply to StackOverflow#3790454for everything about
the many different string styles in YAML.Control indent and width of the results:pyaml.dump(wide_and_deep, indent=4, width=120)These are actually keywords for PyYAML Emitter (passed to it from Dumper),
see more info on these inPyYAML docs.Dump multiple yaml documents into a file:pyaml.dump_all([data1,data2, data3], dst_file)explicit_start=True is implied, unless overidden by explicit_start=False.Control thresholds for vertical spacing of values (0 = always space stuff out),
and clump all oneliner ones at the top:>>> pyaml.dump( data,
  sort_dicts=pyaml.PYAMLSort.oneline_group,
  vspacing=dict(split_lines=0, split_count=0) )

chart:
  axisCenteredZero: no
  axisColorMode: text
  axisLabel: ''
  axisPlacement: auto
  barAlignment: 0
  drawStyle: line
  ...

  hideFrom:
    legend: no
    tooltip: no
    viz: no

  scaleDistribution:
    type: linear

  stacking:
    group: A
    mode: noneOr same thing with cli tool-v/--vspacingoption:pyaml-v0/0g mydata.yamlInstallationIt’s a regular Python 3.8+ module/package, published on PyPI (aspyaml).Module usesPyYAMLfor processing of the actual YAML files
and should pull it in as a dependency.Dependency onunidecodemodule is optional and should only be useful
with force_embed=False keyword (defaults to True), and same-id objects
or recursion is used within serialized data - i.e. only when generating
&some_key_id anchors is needed.
If module is unavailable at runtime, anchor ids will be less like their
keys and maybe not as nice.Usingpipis how you generally install it, usually coupled withvenvusage
(which will also provide “pip” tool itself):% pip install pyamlCurrent-git version can be installed like this:% pip install git+https://github.com/mk-fg/pretty-yamlpip will default to installing into currently-active venv, then user’s home
directory (under~/.local/lib/python...), and maybe system-wide when running
as root (only useful in specialized environments like docker containers).There are many other python packaging tools -pipenv,poetry,pdm, etc -
use whatever is most suitable for specific project/environment.pipxcan be used to install command-line script without a module.More general info on python packaging can be found atpackaging.python.org.When changing code, unit tests can be run withpython-munittestfrom the local repository checkout.