README

level-task-runner

What is it?

A task runner for Nx that allows caching of operations such as lint, test, build to be cached using LevelUP.

Right now, Nx will cache the output of operations in the node_modules/.cache/nx directory. With this package, you can use any LevelDOWN driver to cache your build operations. For example, you can save the outputs of each app/lib in Nx in Redis or S3, etc.

This speeds up your CICD process. Like...significantly.

How do I install it?

Install this package and some leveldown driver.

Yarn:

yarn add @smallstack/cached-task-runner redisdown --dev

NPM:

npm install @smallstack/cached-task-runner redisdown --dev

Okay, how do I use it?

In your nx.json file, add the following right after implicitDependencies:

  "tasksRunnerOptions": {
    "default": {
      "runner": "@smallstack/cached-task-runner",
      "options": {
        "cacheableOperations": ["build", "test", "lint"],
        "levelTaskRunnerOptions": {
          "driver": "redisdown",
          "name": "my-build-cache",
          "host": "10.11.12.13",
          "port": 6379
        }
      }
    }
  },

...and that's it.

What if I need to pass additional options for my redisdown/s3down/someOtherDown?

Add whatever you need in the levelTaskRunnerOptions object. For example, with redisdown, you can use options from node_redis. One of these options is in node_redis is password, so:

  "tasksRunnerOptions": {
    "default": {
      "runner": "@smallstack/cached-task-runner",
      "options": {
        "cacheableOperations": ["build", "test", "lint"],
        "levelTaskRunnerOptions": {
          "driver": "redisdown",
          "name": "my-build-cache",
          "host": "10.11.12.13",
          "port": 6379,
          "password": "hunter2"
        }
      }
    }
  },

But I have different options for dev. env. than Jenkins/GithubActions/Gitlab/CICD_Pipeline...

No problem! Anything that you can supply in levelTaskRunnerOptions in nx.json, you can also supply as environment variables. The environment variables take precedence over what is in nx.json. So you can keep levelTaskRunnerOptions empty so that level-task-runner is not even used in dev, but then supply these options as environment variables in your CI environment.

To supply these options using environment variables, prefix any variable with level_task_runner_. For example:

level_task_runner_driver=redisdown level_task_runner_host=10.11.12.13 level_task_runner_port=6379 level_task_runner_time_to_live=1 yarn lint lib-name

Can I supply a name for the DB? Like if you give a name in redisdown, it uses it as the Redis namespace.

Yes, you can use the option name in levelTaskRunnerOptions or level_task_runner_name as an environment variable.

The name parameter will be given as the first argument to the constructor of the leveldown adapter.

For example, for the s3leveldown adapter, the name parameter will get used as the S3 bucket name.

How is cache evicted?

There is an option call time_to_live (in seconds) that tries to set the Redis expiry if the driver is redisdown.

However, you can setup your Redis cache to automatically evict old entries. See https://redis.io/topics/lru-cache.

Usage no npm install needed!