TOML processor - jq wrapper for YAML, XML, TOML documents¶

Installation¶

pip install yq

Before using yq, you also have to install its dependency, jq. See the jq installation instructions for details and directions specific to your platform.

On macOS, yq is also available on Homebrew: use brew install python-yq.

Synopsis¶

yq takes YAML input, converts it to JSON, and pipes it to jq:

cat input.yml | yq .foo.bar

Like in jq, you can also specify input filename(s) as arguments:

yq .foo.bar input.yml

By default, no conversion of jq output is done. Use the --yaml-output/-y option to convert it back into YAML:

cat input.yml | yq -y .foo.bar

Mapping key order is preserved. By default, custom YAML tags and styles in the input are ignored. Use the --yaml-roundtrip/-Y option to preserve YAML tags and styles by representing them as extra items in their enclosing mappings and sequences while in JSON:

yq -Y .foo.bar input.yml

yq can be called as a module if needed. With -y/-Y, files can be edited in place like with sed -i:

python -m yq -Y --indentless --in-place '.["current-context"] = "staging-cluster"' ~/.kube/config

Use the --width/-w option to pass the line wrap width for string literals; --width 0 disables wrapping. Use --explicit-start/--explicit-end to emit YAML start/end markers even when processing a single document. YAML output preserves an explicit leading --- from the input and emits one for multidocument streams. All other command line arguments are forwarded to jq. yq forwards the exit code jq produced, unless there was an error in YAML parsing, in which case the exit code is 1. See the jq manual for more details on jq features and options.

Because YAML treats JSON as a dialect of YAML, you can use yq to convert JSON to YAML: yq -y . < in.json > out.yml.

Preserving tags, styles, and comments using the `-Y` (`--yaml-roundtrip`) option¶

The -Y option helps preserve custom string styles and tags in your document. For example, consider the following document (an AWS CloudFormation template fragment):

Resources:
  ElasticLoadBalancer:
    Type: 'AWS::ElasticLoadBalancing::LoadBalancer'
    Properties:
      AvailabilityZones: !GetAZs ''
      Instances:
        - !Ref Ec2Instance1
        - !Ref Ec2Instance2
      Description: >-
        Load balancer for Big Important Service.

        Good thing it's managed by this template.

Passing this document through yq -y .Resources.ElasticLoadBalancer will drop custom tags, such as !Ref, and styles, such as the folded style of the Description field:

Type: AWS::ElasticLoadBalancing::LoadBalancer
Properties:
  AvailabilityZones: ''
  Instances:
    - Ec2Instance1
    - Ec2Instance2
  Description: 'Load balancer for Big Important Service.

    Good thing it''s managed by this template.'

By contrast, passing it through yq -Y .Resources.ElasticLoadBalancer will preserve tags, styles, and comments:

Type: 'AWS::ElasticLoadBalancing::LoadBalancer'
Properties:
  AvailabilityZones: !GetAZs ''
  Instances:
    - !Ref 'Ec2Instance1'
    - !Ref 'Ec2Instance2'
  Description: >-
    Load balancer for Big Important Service.

    Good thing it's managed by this template.

To accomplish this in -Y mode, yq carries extra metadata (mapping pairs and sequence values) in the JSON representation of your document for any custom tags or styles that it finds. When converting the JSON back into YAML, it parses this metadata, re-applies the tags and styles, and discards the extra pairs and values.

YAML comment metadata is attached to entries in mappings and sequences. Comments on a document whose root is a scalar (a string, number, boolean, or null) cannot currently roundtrip through -Y: there is no enclosing collection to carry their metadata through jq. For example, a Markdown heading after a YAML document separator is treated as a comment on a root string and is lost. Use --yaml-frontmatter/-F for these files to preserve the entire body.

Warning

The -Y option is incompatible with jq filters that do not expect the extra information injected into the document to preserve the YAML formatting. For example, a jq filter that counts entries in the Instances array will come up with 4 entries instead of 2. A filter that expects all array entries to be mappings may break due to the presence of string metadata keys. Check your jq filter for compatibility/semantic validity when using the -Y option.

YAML frontmatter¶

Use --yaml-frontmatter/-F to process a YAML header followed by Markdown or other text:

yq -Y --yaml-frontmatter '.draft = false' post.md
yq -iYF '.draft = false' post.md another-post.md

Only the first document is sent to jq. An initial --- opens the header; an unindented --- or ... document marker closes it. With -y or -Y, the closing delimiter and everything after it pass through unchanged, including comments, whitespace, and line endings. The filter must produce exactly one document, and each invocation accepts one input file (or multiple files with --in-place). A header without a closing delimiter is processed as ordinary YAML. Without -y/-Y, only the JSON query result is emitted, allowing queries such as yq -F .title post.md. The -f option still means jq’s --from-file.

XML support¶

yq also supports XML. The yq package installs an executable, xq, which transcodes XML to JSON using xmltodict and pipes it to jq. Roundtrip transcoding is available with the xq --xml-output/xq -x option. Multiple XML documents can be passed in separate files/streams as xq a.xml b.xml. Use --xml-item-depth to descend into large documents, streaming their contents without loading the full doc into memory (for example, stream a Wikipedia database dump with cat enwiki-*.xml.bz2 | bunzip2 | xq . --xml-item-depth=2). Entity expansion and DTD resolution is disabled to avoid XML parsing vulnerabilities. Use python -m yq.xq if you want to ensure a specific Python runtime.

TOML support¶

yq supports TOML as well. The yq package installs an executable, tomlq, which uses the tomlkit library to transcode TOML to JSON, then pipes it to jq. Roundtrip transcoding is available with the tomlq --toml-output/tomlq -t option. Use tomlq --toml-roundtrip/tomlq -T to preserve TOML comments, whitespace, and formatting metadata while editing. Use python -m yq.tomlq if you want to ensure a specific Python runtime.

Compatibility note

This package’s release series available on PyPI begins with version 2.0.0. Versions of yq prior to 2.0.0 are distributed by https://github.com/abesto/yq and are not related to this package. No guarantees of compatibility are made between abesto/yq and kislyuk/yq. This package follows the Semantic Versioning 2.0.0 standard. To ensure proper operation, declare dependency version ranges according to SemVer.

Authors¶

Andrey Kislyuk

Links¶

Project home page (GitHub)
Documentation
Package distribution (PyPI)
Change log
jq - the command-line JSON processor utility powering yq

Bugs¶

Please report bugs, issues, feature requests, etc. on GitHub.

License¶

Licensed under the terms of the Apache License, Version 2.0.

CLI usage¶

yq¶

usage: yq [options] <jq filter> [input file...]
          [--indentless-lists] [--explicit-start] [--explicit-end]
          [--in-place] [--version]
          [jq_filter] [files ...]

yq: Command-line YAML processor - jq wrapper for YAML documents

yq transcodes YAML documents to JSON and passes them to jq.
See https://github.com/kislyuk/yq for more information.

positional arguments:
  jq_filter
  files

options:
  -h, --help            show this help message and exit
  --yaml-output, --yml-output, -y
                        Transcode jq JSON output back into YAML and emit it
  --yaml-roundtrip, --yml-roundtrip, -Y
                        Transcode jq JSON output back into YAML and emit it. Preserve YAML tags and styles by representing them as extra items in their enclosing mappings and sequences while in JSON. This option is incompatible with jq filters that do not expect these extra items.
  --yaml-output-grammar-version {1.1,1.2}, --yml-out-ver {1.1,1.2}
                        When using --yaml-output, specify output grammar (the default is 1.1 and will be changed to 1.2 in a future version). Setting this to 1.2 will cause strings like 'on' and 'no' to be emitted unquoted.
  --width WIDTH, -w WIDTH
                        When using --yaml-output, specify string wrap width (0 disables wrapping)
  --indentless-lists, --indentless
                        When using --yaml-output, indent block style lists (sequences) with 0 spaces instead of 2
  --explicit-start      When using --yaml-output, always emit explicit document start ("---")
  --explicit-end        When using --yaml-output, always emit explicit document end ("...")
  --in-place, -i        Edit files in place (no backup - use caution)
  --version             show program's version number and exit

jq - commandline JSON processor [version 1.6]

Usage:	jq [options] <jq filter> [file...]
	jq [options] --args <jq filter> [strings...]
	jq [options] --jsonargs <jq filter> [JSON_TEXTS...]

jq is a tool for processing JSON inputs, applying the given filter to
its JSON text inputs and producing the filter's results as JSON on
standard output.

The simplest filter is ., which copies jq's input to its output
unmodified (except for formatting, but note that IEEE754 is used
for number representation internally, with all that that implies).

For more advanced filters see the jq(1) manpage ("man jq")
and/or https://stedolan.github.io/jq

Example:

	$ echo '{"foo": 0}' | jq .
	{
		"foo": 0
	}

Some of the options include:
  -c               compact instead of pretty-printed output;
  -n               use `null` as the single input value;
  -e               set the exit status code based on the output;
  -s               read (slurp) all inputs into an array; apply filter to it;
  -r               output raw strings, not JSON texts;
  -R               read raw strings, not JSON texts;
  -C               colorize JSON;
  -M               monochrome (don't colorize JSON);
  -S               sort keys of objects on output;
  --tab            use tabs for indentation;
  --arg a v        set variable $a to value <v>;
  --argjson a v    set variable $a to JSON value <v>;
  --slurpfile a f  set variable $a to an array of JSON texts read from <f>;
  --rawfile a f    set variable $a to a string consisting of the contents of <f>;
  --args           remaining arguments are string arguments, not files;
  --jsonargs       remaining arguments are JSON arguments, not files;
  --               terminates argument processing;

Named arguments are also available as $ARGS.named[], while
positional arguments are available as $ARGS.positional[].

See the manpage for more options.

xq¶

usage: xq [options] <jq filter> [input file...]
          [--xml-short-empty-elements] [--in-place] [--version]
          [jq_filter] [files ...]

xq: Command-line XML processor - jq wrapper for XML documents

xq transcodes XML documents to JSON and passes them to jq.
See https://github.com/kislyuk/xq for more information.

positional arguments:
  jq_filter
  files

options:
  -h, --help            show this help message and exit
  --xml-output, -x      Transcode jq JSON output back into XML and emit it
  --xml-item-depth 123  Specify depth of items to emit (default 0; use a positive integer to stream large docs)
  --xml-dtd             Preserve XML Document Type Definition (disables streaming of multiple docs)
  --xml-root XML_ROOT   When transcoding back to XML, envelope the output in an element with this name
  --xml-force-list ELT  Emit a list for elements with this name even if they occur only once (option can repeat)
  --xml-short-empty-elements
                        When transcoding back to XML, emit empty tags as self-closing tags
  --in-place, -i        Edit files in place (no backup - use caution)
  --version             show program's version number and exit

jq - commandline JSON processor [version 1.6]

Usage:	jq [options] <jq filter> [file...]
	jq [options] --args <jq filter> [strings...]
	jq [options] --jsonargs <jq filter> [JSON_TEXTS...]

jq is a tool for processing JSON inputs, applying the given filter to
its JSON text inputs and producing the filter's results as JSON on
standard output.

The simplest filter is ., which copies jq's input to its output
unmodified (except for formatting, but note that IEEE754 is used
for number representation internally, with all that that implies).

For more advanced filters see the jq(1) manpage ("man jq")
and/or https://stedolan.github.io/jq

Example:

	$ echo '{"foo": 0}' | jq .
	{
		"foo": 0
	}

Some of the options include:
  -c               compact instead of pretty-printed output;
  -n               use `null` as the single input value;
  -e               set the exit status code based on the output;
  -s               read (slurp) all inputs into an array; apply filter to it;
  -r               output raw strings, not JSON texts;
  -R               read raw strings, not JSON texts;
  -C               colorize JSON;
  -M               monochrome (don't colorize JSON);
  -S               sort keys of objects on output;
  --tab            use tabs for indentation;
  --arg a v        set variable $a to value <v>;
  --argjson a v    set variable $a to JSON value <v>;
  --slurpfile a f  set variable $a to an array of JSON texts read from <f>;
  --rawfile a f    set variable $a to a string consisting of the contents of <f>;
  --args           remaining arguments are string arguments, not files;
  --jsonargs       remaining arguments are JSON arguments, not files;
  --               terminates argument processing;

Named arguments are also available as $ARGS.named[], while
positional arguments are available as $ARGS.positional[].

See the manpage for more options.

tomlq¶

usage: tomlq [options] <jq filter> [input file...]

tomlq: Command-line TOML processor - jq wrapper for TOML documents

tomlq transcodes TOML documents to JSON and passes them to jq.
See https://github.com/kislyuk/tomlq for more information.

positional arguments:
  jq_filter
  files

options:
  -h, --help            show this help message and exit
  --toml-output, -t     Transcode jq JSON output back into TOML and emit it
  --toml-roundtrip, -T  Transcode jq JSON output back into TOML and emit it. Preserve TOML comments, whitespace, and other formatting metadata by representing them as extra items while in JSON.
  --in-place, -i        Edit files in place (no backup - use caution)
  --version             show program's version number and exit

jq - commandline JSON processor [version 1.6]

Usage:	jq [options] <jq filter> [file...]
	jq [options] --args <jq filter> [strings...]
	jq [options] --jsonargs <jq filter> [JSON_TEXTS...]

jq is a tool for processing JSON inputs, applying the given filter to
its JSON text inputs and producing the filter's results as JSON on
standard output.

The simplest filter is ., which copies jq's input to its output
unmodified (except for formatting, but note that IEEE754 is used
for number representation internally, with all that that implies).

For more advanced filters see the jq(1) manpage ("man jq")
and/or https://stedolan.github.io/jq

Example:

	$ echo '{"foo": 0}' | jq .
	{
		"foo": 0
	}

Some of the options include:
  -c               compact instead of pretty-printed output;
  -n               use `null` as the single input value;
  -e               set the exit status code based on the output;
  -s               read (slurp) all inputs into an array; apply filter to it;
  -r               output raw strings, not JSON texts;
  -R               read raw strings, not JSON texts;
  -C               colorize JSON;
  -M               monochrome (don't colorize JSON);
  -S               sort keys of objects on output;
  --tab            use tabs for indentation;
  --arg a v        set variable $a to value <v>;
  --argjson a v    set variable $a to JSON value <v>;
  --slurpfile a f  set variable $a to an array of JSON texts read from <f>;
  --rawfile a f    set variable $a to a string consisting of the contents of <f>;
  --args           remaining arguments are string arguments, not files;
  --jsonargs       remaining arguments are JSON arguments, not files;
  --               terminates argument processing;

Named arguments are also available as $ARGS.named[], while
positional arguments are available as $ARGS.positional[].

See the manpage for more options.