Prettify YAML with comments - yaml

Question

1. Summary
I can't find, how I can automatically prettify my YAML files.
2. Data
Example:
    I have SashaPrettifyYAML.yaml file:
sasha_commands:
# Sasha comment
sasha_command_help: {call: sublime.command_help, caption: 'Sasha Command: Command Help'}
3. Expected behavior
I want to delete {braces}:
sasha_commands:
# Sasha comment
sasha_command_help:
call: sublime.command_help
caption: 'Sasha Command: Command Help'
4. Not helped
Pretty YAML (based on PyYAML) and online formatters as YAML Formatter and OnlineYAMLTools delete comments;
I can't find the required option in ruamel.yaml.cmd;
align-yaml align, not prettify YAML file.

Answer 1

There is no option to do this in ruamel.yaml.cmd, but it is fairly straightforward to do this with a small python program and using ruamel.yaml, by loading and dumping in round-trip mode (the default).
The only thing you need to do is make sure the flow-style on the data-structure that is the value for the key sasha_command_help is set to block-style (which is how I interpret your definition of "prettifying YAML"):
import sys
import ruamel.yaml
yaml_str = """\
sasha_commands:
# Sasha comment
sasha_command_help: {call: sublime.command_help, caption: 'Sasha Command: Command Help'}
"""
yaml = ruamel.yaml.YAML()
yaml.preserve_quotes = True
data = yaml.load(yaml_str)
data['sasha_commands']['sasha_command_help'].fa.set_block_style()
yaml.dump(data, sys.stdout)
this will exactly give the output you expect.
A recursive data structure walker can be found in scalarstring.py in the ruamel.yaml source, and adapted to make a generic "make-everything-block-style" routine:
import sys
import ruamel.yaml
def block_style(base):
"""
This routine walks over a simple, i.e. consisting of dicts, lists and
primitives, tree loaded from YAML. It recurses into dict values and list
items, and sets block-style on these.
"""
if isinstance(base, dict):
for k in base:
try:
base.fa.set_block_style()
except AttributeError:
pass
block_style(base[k])
elif isinstance(base, list):
for elem in base:
try:
base.fa.set_block_style()
except AttributeError:
pass
block_style(elem)
yaml = ruamel.yaml.YAML()
yaml.preserve_quotes = True
file_in = sys.argv[1]
file_out = sys.argv[2]
with open(file_in) as fp:
data = yaml.load(fp)
block_style(data)
with open(file_out, 'w') as fp:
yaml.dump(data, fp)
If you store the above in prettifyyaml.py you can call it with:
python prettifyyaml.py SashaPrettifyYAML.yaml Prettified.yaml
Since you are already using single quotes around the scalar that has embedded spaces, you won't see a change if you leave out yaml.preserve_quotes = True. But if you had used a double quoted scalar then that line makes sure the double quotes are preserved.

Answer 2

I had the same problem. I wrote my own YAML beautifier https://github.com/wangkuiyi/yamlfmt. I hope it helps.
I tried top results from Google, but none of them address the requirements of https://sqlflow.org/sqlflow, which I am leading:
https://pypi.org/project/yamlfmt cannot handle a file of multiple YAML documents separated by ---
https://github.com/devopyio/yamlfmt cannot handle multiple files.
https://github.com/miekg/yamlfmt/blob/master/fmt.go cannot replace (inline edit) the input files.

Answer 3

You can use yq tool - it's easy to install and use, and it's well maintained.
Supposing you have example.yml file to format, it can be processed by following ways:
from file: yq r --unwrapScalar -p pv -P example.yml '*'
from stdin: cat example.yml | yq r --unwrapScalar -p pv -P - '*'