bazel-lib/docs/yq.md

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<!-- Generated with Stardoc: http://skydoc.bazel.build -->
Public API for yq
<a id="yq"></a>
## yq
<pre>
yq(<a href="#yq-name">name</a>, <a href="#yq-srcs">srcs</a>, <a href="#yq-expression">expression</a>, <a href="#yq-args">args</a>, <a href="#yq-outs">outs</a>, <a href="#yq-kwargs">kwargs</a>)
</pre>
Invoke yq with an expression on a set of input files.
For yq documentation, see https://mikefarah.gitbook.io/yq.
To use this rule you must register the yq toolchain in your WORKSPACE:
```starlark
load("@aspect_bazel_lib//lib:repositories.bzl", "register_yq_toolchains")
register_yq_toolchains()
```
Usage examples:
```starlark
load("@aspect_bazel_lib//lib:yq.bzl", "yq")
```
```starlark
# Remove fields
yq(
name = "safe-config",
srcs = ["config.yaml"],
expression = "del(.credentials)",
)
```
```starlark
# Merge two yaml documents
yq(
name = "ab",
srcs = [
"a.yaml",
"b.yaml",
],
expression = ". as $item ireduce ({}; . * $item )",
)
```
```starlark
# Split a yaml file into several files
yq(
name = "split",
srcs = ["multidoc.yaml"],
outs = [
"first.yml",
"second.yml",
],
args = [
"-s '.a'", # Split expression
"--no-doc", # Exclude document separator --
],
)
```
```starlark
# Convert a yaml file to json
yq(
name = "convert-to-json",
srcs = ["foo.yaml"],
args = ["-o=json"],
outs = ["foo.json"],
)
```
```starlark
# Convert a json file to yaml
yq(
name = "convert-to-yaml",
srcs = ["bar.json"],
args = ["-P"],
outs = ["bar.yaml"],
)
```
```starlark
# Call yq in a genrule
genrule(
name = "generate",
srcs = ["farm.yaml"],
outs = ["genrule_output.yaml"],
cmd = "$(YQ_BIN) '.moo = "cow"' $(location farm.yaml) > $@",
toolchains = ["@yq_toolchains//:resolved_toolchain"],
)
```
```starlark
# With --stamp, causes properties to be replaced by version control info.
yq(
name = "stamped",
srcs = ["package.yaml"],
expression = "|".join([
"load(strenv(STAMP)) as $stamp",
# Provide a default using the "alternative operator" in case $stamp is empty dict.
".version = ($stamp.BUILD_EMBED_LABEL // "<unstamped>")",
]),
)
```
yq is capable of parsing and outputting to other formats. See their [docs](https://mikefarah.gitbook.io/yq) for more examples.
**PARAMETERS**
| Name | Description | Default Value |
| :------------- | :------------- | :------------- |
| <a id="yq-name"></a>name | Name of the rule | none |
| <a id="yq-srcs"></a>srcs | List of input file labels | none |
| <a id="yq-expression"></a>expression | yq expression (https://mikefarah.gitbook.io/yq/commands/evaluate). Defaults to the identity expression ".". Subject to stamp variable replacements, see [Stamping](./stamping.md). When stamping is enabled, an environment variable named "STAMP" will be available in the expression.<br><br>Be careful to write the filter so that it handles unstamped builds, as in the example above. | <code>"."</code> |
| <a id="yq-args"></a>args | Additional args to pass to yq. Note that you do not need to pass _eval_ or _eval-all_ as this is handled automatically based on the number <code>srcs</code>. Passing the output format or the parse format is optional as these can be guessed based on the file extensions in <code>srcs</code> and <code>outs</code>. | <code>[]</code> |
| <a id="yq-outs"></a>outs | Name of the output files. Defaults to a single output with the name plus a ".yaml" extension, or the extension corresponding to a passed output argment (e.g., "-o=json"). For split operations you must declare all outputs as the name of the output files depends on the expression. | <code>None</code> |
| <a id="yq-kwargs"></a>kwargs | Other common named parameters such as <code>tags</code> or <code>visibility</code> | none |