yq

yq: Command-line YAML/XML/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 <https://stedolan.github.io/jq/download/>_ for details and directions specific to your platform.

On macOS, yq is also available on Homebrew <https://brew.sh/>_: use brew install python-yq.

Synopsis

yq takes YAML input, converts it to JSON, and pipes it to jq <https://stedolan.github.io/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 <http://www.yaml.org/spec/1.2/spec.html#id2764295>_ and styles <https://yaml.org/spec/1.2.2/#3231-node-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 <https://stedolan.github.io/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 <https://yaml-multiline.info/>`_ and
`tags <https://camel.readthedocs.io/en/latest/yamlref.html#tags>`_ in your document. For example, consider the following
document (an `AWS CloudFormation <https://aws.amazon.com/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 <https://yaml-multiline.info/>`_ 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 <https://www.xml.com/pub/a/2006/05/31/converting-between-xml-and-json.html>`_ using
`xmltodict <https://github.com/martinblech/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 <https://dumps.wikimedia.org>`_ 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 <https://toml.io/>`_ as well. The ``yq`` package installs an executable, ``tomlq``, which uses the
`tomlkit library <https://github.com/sdispater/tomlkit>`_ 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.

.. admonition:: 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 <http://semver.org/>`_
 standard. To ensure proper operation, declare dependency version ranges according to SemVer.

Authors
-------
* Andrey Kislyuk

Links
-----
* `Project home page (GitHub) <https://github.com/kislyuk/yq>`_
* `Documentation <https://kislyuk.github.io/yq/>`_
* `Package distribution (PyPI) <https://pypi.python.org/pypi/yq>`_
* `Change log <https://github.com/kislyuk/yq/blob/master/Changes.rst>`_
* `jq <https://stedolan.github.io/jq/>`_ - the command-line JSON processor utility powering ``yq``

Bugs
~~~~
Please report bugs, issues, feature requests, etc. on `GitHub <https://github.com/kislyuk/yq/issues>`_.

License
-------
Licensed under the terms of the `Apache License, Version 2.0 <http://www.apache.org/licenses/LICENSE-2.0>`_.