Public API for jq
## jq
jq(name, srcs, filter, filter_file, args, out, kwargs)
Invoke jq with a filter on a set of json input files.
For jq documentation, see https://stedolan.github.io/jq/.
Usage examples:
```starlark
load("@aspect_bazel_lib//lib:jq.bzl", "jq")
# Create a new file bazel-out/.../no_srcs.json
jq(
name = "no_srcs",
srcs = [],
filter = ".name = "Alice"",
)
# Remove fields from package.json.
# Writes to bazel-out/.../package.json which means you must refer to this as ":no_dev_deps"
# since Bazel doesn't allow a label for the output file that collides with the input file.
jq(
name = "no_dev_deps",
srcs = ["package.json"],
filter = "del(.devDependencies)",
)
# Merge bar.json on top of foo.json, producing foobar.json
jq(
name = "merged",
srcs = ["foo.json", "bar.json"],
filter = ".[0] * .[1]",
args = ["--slurp"],
out = "foobar.json",
)
# Long filters can be split over several lines with comments
jq(
name = "complex",
srcs = ["a.json", "b.json"],
filter = """
.[0] as $a
# Take select fields from b.json
| (.[1] | {foo, bar, tags}) as $b
# Merge b onto a
| ($a * $b)
# Combine 'tags' array from both
| .tags = ($a.tags + $b.tags)
# Add new field
+ {\"aspect_is_cool\": true}
""",
args = ["--slurp"],
)
# Load filter from a file
jq(
name = "merged",
srcs = ["foo.json", "bar.json"],
filter_file = "filter.txt",
args = ["--slurp"],
out = "foobar.json",
)
# Convert genquery output to json
genquery(
name = "deps",
expression = "deps(//some:target)",
scope = ["//some:target"],
)
jq(
name = "deps_json",
srcs = [":deps"],
args = [
"--raw-input",
"--slurp",
],
filter = "{ deps: split("\n") | map(select(. | length > 0)) }",
)
# With --stamp, causes properties to be replaced by version control info.
jq(
name = "stamped",
srcs = ["package.json"],
filter = "|".join([
# Don't directly reference $STAMP as it's only set when stamping
# This 'as' syntax results in $stamp being null in unstamped builds.
"$ARGS.named.STAMP as $stamp",
# Provide a default using the "alternative operator" in case $stamp is null.
".version = ($stamp[0].BUILD_EMBED_LABEL // "<unstamped>")",
]),
)
```
You could also use it directly from a `genrule` by referencing the toolchain, and the `JQ_BIN`
"Make variable" it exposes:
```
genrule(
name = "case_genrule",
srcs = ["a.json"],
outs = ["genrule_output.json"],
cmd = "$(JQ_BIN) '.' $(location a.json) > $@",
toolchains = ["@jq_toolchains//:resolved_toolchain"],
)
```
**PARAMETERS**
| Name | Description | Default Value |
| :------------- | :------------- | :------------- |
| name | Name of the rule | none |
| srcs | List of input files. May be empty. | none |
| filter | Filter expression (https://stedolan.github.io/jq/manual/#Basicfilters). Subject to stamp variable replacements, see [Stamping](./stamping.md). When stamping is enabled, a variable named "STAMP" will be available in the filter.
Be careful to write the filter so that it handles unstamped builds, as in the example above. | None |
| filter_file | File containing filter expression (alternative to filter) | None |
| args | Additional args to pass to jq | [] |
| out | Name of the output json file; defaults to the rule name plus ".json" | None |
| kwargs | Other common named parameters such as tags or visibility | none |