1e3fef6ab0
It's possible (quite common on Kubernetes) to have a service discovery return thousands of targets then drop most of them in relabel rules. The main place this data is used is to display in the web UI, where you don't want thousands of lines of display. The new limit is `keep_dropped_targets`, which defaults to 0 for backwards-compatibility. Signed-off-by: Bryan Boreham <bjboreham@gmail.com> |
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| .. | ||
| module | ||
| react-app | ||
| static | ||
| .gitignore | ||
| .nvmrc | ||
| README.md | ||
| assets_embed.go | ||
| build_ui.sh | ||
| embed.go.tmpl | ||
| package-lock.json | ||
| package.json | ||
| ui.go | ||
README.md
Overview
The ui directory contains static files and templates used in the web UI. For
easier distribution they are compressed (c.f. Makefile) and statically compiled
into the Prometheus binary using the embed package.
During development it is more convenient to always use the files on disk to
directly see changes without recompiling.
To make this work, remove the builtinassets build tag in the flags entry
in .promu.yml, and then make build (or build Prometheus using
go build ./cmd/prometheus).
This will serve all files from your local filesystem. This is for development purposes only.
React-app
Introduction
The react application is a monorepo composed by multiple different npm packages. The main one is react-app which
contains the code of the react application.
Then you have different npm packages located in the folder modules. These packages are supposed to be used by the
react-app and also by others consumers (like Thanos)
Pre-requisite
To be able to build the react application you need:
- npm >= v7
- node >= v16
Installing npm dependencies
The React UI depends on a large number of npm packages. These are not checked in, so you will
need to move to the directory web/ui and then download and install them locally via the npm package manager:
npm install
npm consults the package.json and package-lock.json files for dependencies to install. It creates a node_modules
directory with all installed dependencies.
NOTE: Do not run npm install in the react-app folder or in any sub folder of the module directory.
Upgrading npm dependencies
As it is a monorepo, when upgrading a dependency, you have to upgrade it in every packages that composed this monorepo (
aka, in all sub folder of module and in react-app)
Then you have to run the command npm install in web/ui and not in a sub folder / sub package. It won't simply work.
Running a local development server
You can start a development server for the React UI outside of a running Prometheus server by running:
npm start
This will open a browser window with the React app running on http://localhost:3000/. The page will reload if you make edits to the source code. You will also see any lint errors in the console.
NOTE: It will reload only if you change the code in react-app folder. Any code changes in the folder module is
not considered by the command npm start. In order to see the changes in the react-app you will have to
run npm run build:module
Due to a "proxy": "http://localhost:9090" setting in the package.json file, any API requests from the React UI are
proxied to localhost on port 9090 by the development server. This allows you to run a normal Prometheus server to
handle API requests, while iterating separately on the UI.
[browser] ----> [localhost:3000 (dev server)] --(proxy API requests)--> [localhost:9090 (Prometheus)]
Running tests
To run the test for the react-app and for all modules, you can simply run:
npm test
if you want to run the test only for a specific module, you need to go to the folder of the module and run
again npm test.
For example, in case you only want to run the test of the react-app, go to web/ui/react-app and run npm test
To generate an HTML-based test coverage report, run:
CI=true npm test:coverage
This creates a coverage subdirectory with the generated report. Open coverage/lcov-report/index.html in the browser
to view it.
The CI=true environment variable prevents the tests from being run in interactive / watching mode.
See the Create React App documentation for more information about running tests.
Building the app for production
To build a production-optimized version of the React app to a build subdirectory, run:
npm run build
NOTE: You will likely not need to do this directly. Instead, this is taken care of by the build target in the main
Prometheus Makefile when building the full binary.
Integration into Prometheus
To build a Prometheus binary that includes a compiled-in version of the production build of the React app, change to the root of the repository and run:
make build
This installs dependencies via npm, builds a production build of the React app, and then finally compiles in all web assets into the Prometheus binary.