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Trying Glean

We provide a Docker image containing a pre-built set of Glean binaries that you can try out. These images are built automatically by a Github Action.

Pull the latest demo Docker image (warning, this is around 7GB):

docker pull ghcr.io/facebookincubator/glean/demo:latest

Run it:

docker run -it -p 8888:8888 ghcr.io/facebookincubator/glean/demo:latest
info

What's in the image?

  • A build of Glean, in /glean-code
  • The flow binary, in /usr/local/bin/flow
  • A checkout of react in /react-code
  • A Glean database containing the Flow index of React in /gleandb

Start the Glean shell:

glean shell --db-root /glean-demo/db --schema /glean-demo/schema/source

You should see:

Glean Shell, built on <time>, from rev <unknown>
type :help for help.
>

The demo image contains a pre-generated database containing the results of running the Flow indexer on the React repository:

> :list
react/0 (complete)
  Created: 2021-05-24T02:42:33Z (30 days, 9 hours ago)

We can look at the contents:

react> :db react
using database react/0
react> :stat
flow.Declaration.3
  count: 26756
  size:  888756 (867.93 kB) 4.8248%
...
Total size: 17.57 MB

Running the server​

Above we showed the shell reading the database from the filesystem directly. Instead we can run a server that the clients will interact with to make queries:

glean-server --db-root /glean-demo/db --schema /glean-demo/schema/source --port 12345

And now the shell can connect to the server:

glean shell --service localhost:12345

The commands work exactly the same as with local databases, but now it would also work over the network.

We have a small demo showing how Glean can enable code navigation. The glean-hyperlink tool creates a webserver that serves hyperlinked source code using data from a specified Glean database.

We can navigate the React source code as follows. First start the Glean server:

glean-server --db-root /glean-demo/db --schema /glean-demo/schema/source --port 12345

Next start the Hyperlink server:

glean-hyperlink --service localhost:12345 --db react --root /react-code --http 8888

Now navigate to http://localhost:8888 in your browser, and you should see a list of source files. Click on a file, and navigate around the code by clicking on a symbol reference to jump to its definition. Try something substantial like react-dom/src/client/ReactDOMComponent.js (http://localhost:8888/packages/react-dom/src/client/ReactDOMComponent.js) - note how Glean is accurately linking both local and imported symbols.