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After the recent changes to limit the dev-cli watcher to relevant packages, the watcher started logging tons of unnecessary changes, and in some cases breaking based on the state of the repo. I have seen this happen with Chokidar before, and I'm not convinced we'll be able to fix it, so instead I decided to swap it out with `@parcel/watcher`, which is a conceptually simpler implementation that automatically batches changes and watches an entire directory, rather than tons of unique directories/files. This new implementation is conceptually simpler, and because of the design of the `@parcel/watcher` module I was pushed to reuse the `RepoSourceClassifier` to determine if we should restart the server based on a specific change. This means we now have a single source of truth for test files and the like (the classifier will tell us if a file is a test file, regardless of where it exists in the repo). Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com> |
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| index.ts | ||
| jest.config.js | ||
| jest.integration.config.js | ||
| kibana.jsonc | ||
| package.json | ||
| README.mdx | ||
| tsconfig.json | ||
--- id: kibDevDocsOpsCliDevMode slug: /kibana-dev-docs/ops/cli-dev-mode title: "@kbn/cli-dev-mode" description: A package to manage the Kibana cli behavior when in development date: 2022-05-24 tags: ['kibana', 'dev', 'contributor', 'operations', 'cli', 'dev', 'mode'] --- This package exposes a function that manages the alternate behavior of the Kibana cli when using the `--dev` flag. This mode provides several useful features in a single CLI for a nice developer experience: - automatic server restarts when code changes - runs the `@kbn/optimizer` to build browser bundles - runs a base path proxy which helps developers test that they are writing code which is compatible with custom basePath settings while they work - pauses requests when the server or optimizer are not ready to handle requests so that when users load Kibana in the browser it's always using the code as it exists on disk To accomplish this, and to make it easier to test, the `CliDevMode` class manages the following objects. ## `Watcher` The `Watcher` manages a [@parcel/watcher](https://github.com/parcel-bundler/watcher) instance to watch the server files, logs about file changes observed and provides an observable to the `DevServer` via its `serverShouldRestart$()` method. ## `DevServer` The `DevServer` object is responsible for everything related to running and restarting the Kibana server process: - listens to restart notifications from the `Watcher` object, sending `SIGKILL` to the existing server and launching a new instance with the current code - writes the stdout/stderr logs from the Kibana server to the parent process - gracefully kills the process if the SIGINT signal is sent - kills the server if the SIGTERM signal is sent, process.exit() is used, a second SIGINT is sent, or the graceful shutdown times out - proxies SIGHUP notifications to the child process, though the core team is working on migrating this functionality to the KP and making this unnecessary ## `Optimizer` The `Optimizer` object manages a `@kbn/optimizer` instance, adapting its configuration and logging to the data available to the CLI. ## `BasePathProxyServer` This proxy injects a random three character base path in the URL that Kibana is served from to help ensure that Kibana features are written to adapt to custom base path configurations from users. The basePathProxy also has another important job, ensuring that requests don't fail because the server is restarting and that the browser receives front-end assets containing all saved changes. We accomplish this by observing the ready state of the `Optimizer` and `DevServer` objects and pausing all requests through the proxy until both objects report that they aren't building/restarting based on recently saved changes.