Jsonnet Rules

Rules

• jsonnet_library
• jsonnet_to_json

Overview

These are build rules for working with Jsonnet files with Bazel.

Setup

To use the Jsonnet rules, simply copy the contents of jsonnet.WORKSPACE into your WORKSPACE file.

jsonnet_library

jsonnet_library(name, srcs, deps, imports)

Example

Suppose you have the following directory structure:

[workspace]/
    WORKSPACE
    configs/
      BUILD
      backend.jsonnet
      frontend.jsonnet

You can use the jsonnet_library rule to build a collection of .jsonnet files that can be imported by other .jsonnet files as dependencies:

configs/BUILD:

load("/tools/build_defs/jsonnet/jsonnet", "jsonnet_library")

jsonnet_library(
    name = "configs",
    srcs = [
        "backend.jsonnet",
        "frontend.jsonnet",
    ],
)

jsonnet_to_json

jsonnet_to_json(name, src, deps, outs, multiple_outputs, imports)

{ “foo.json”: foo, } imports List of strings, optional List of import -J flags to be passed to the jsonnet compiler.

Example

Suppose you have the following directory structure:

[workspace]/
    WORKSPACE
    workflows/
        BUILD
        workflow.jsonnet
        wordcount.jsonnet
        intersection.jsonnet

Say that workflow.jsonnet is a base configuration library for a workflow scheduling system and wordcount.jsonnet and intersection.jsonnet both import workflow.jsonnet to define workflows for performing a wordcount and intersection of two files, respectively.

First, create a jsonnet_library target with workflow.jsonnet:

workflows/BUILD:

load("/tools/build_defs/jsonnet/jsonnet", "jsonnet_library")

jsonnet_library(
    name = "workflow",
    srcs = ["workflow.jsonnet"],
)

To compile wordcount.jsonnet and intersection.jsonnet to JSON, define two jsonnet_to_json targets:

jsonnet_to_json(
    name = "wordcount",
    src = "wordcount.jsonnet",
    outs = ["wordcount.json"],
    deps = [":workflow"],
)

jsonnet_to_json(
    name = "intersection",
    src = "intersection.jsonnet",
    outs = ["intersection.json"],
    deps = [":workflow"],
)

Example: Multiple output files

To use Jsonnet's multiple output files, suppose you add a file shell-workflows.jsonnet that imports wordcount.jsonnet and intersection.jsonnet:

workflows/shell-workflows.jsonnet:

local wordcount = import "workflows/wordcount.jsonnet";
local intersection = import "workflows/intersection.jsonnet";

{
  "wordcount-workflow.json": wordcount,
  "intersection-workflow.json": intersection,
}

To compile shell-workflows.jsonnet into the two JSON files, wordcount-workflow.json and intersection-workflow.json, first create a jsonnet_library target containing the two files that shell-workflows.jsonnet depends on:

jsonnet_library(
    name = "shell-workflows-lib",
    srcs = [
        "wordcount.jsonnet",
        "intersection.jsonnet",
    ],
    deps = [":workflow"],
)

Then, create a jsonnet_to_json target and set outs to the list of output files to indicate that multiple output JSON files are generated:

jsonnet_to_json(
    name = "shell-workflows",
    src = "shell-workflows.jsonnet",
    deps = [":shell-workflows-lib"],
    outs = [
        "wordcount-workflow.jsonnet",
        "intersection-workflow.jsonnet",
    ],
)