Livegrep

Livegrep is a tool, partially inspired by Google Code Search, for interactive regex search of ~gigabyte-scale source repositories. You can see a running instance at http://livegrep.com/.

Building

livegrep builds using bazel. You will need to install with a version matching that in .bazelversion. Running bazel via bazelisk will download the right version automatically.

livegrep vendors and/or fetches all of its dependencies using bazel, and so should only require a relatively recent C++ compiler to build.

Once you have those dependencies, you can build using

bazel build //...

Note that the initial build will download around 100M of dependencies. These will be cached once downloaded.

Invoking

To run livegrep, you need to invoke both the codesearch backend index/search process, and the livegrep web interface.

To run the sample web interface over livegrep itself, once you have built both codesearch and livegrep:

In one terminal, start the codesearch server like so:

bazel-bin/src/tools/codesearch -grpc localhost:9999 doc/examples/livegrep/index.json

In another, run livegrep:

bazel-bin/cmd/livegrep/livegrep_/livegrep

In a browser, now visit http://localhost:8910/, and you should see a working livegrep.

Using Index Files

The codesearch binary is responsible for reading source code, maintaining an index, and handling searches. livegrep is stateless and relies only on the connection to codesearch over a TCP connection.

By default, codesearch will build an in-memory index over the repositories specified in its configuration file. You can, however, also instruct it to save the index to a file on disk. This has the dual advantages of allowing indexes that are too large to fit in RAM, and of allowing an index file to be reused. You instruct codesearch to generate an index file via the -dump_index flag and to not launch a search server via the -index_only flag:

bazel-bin/src/tools/codesearch -index_only -dump_index livegrep.idx doc/examples/livegrep/index.json

Once codeseach has built the index, this index file can be used for future runs. Index files are standalone, and you no longer need access to the source code repositories, or even a configuration file, once an index has been built. You can just launch a search server like so:

bazel-bin/src/tools/codesearch -load_index livegrep.idx -grpc localhost:9999

The schema for the codesearch configuration file defined using protobuf in src/proto/config.proto.

livegrep

The livegrep frontend accepts an optional position argument indicating a JSON configuration file; See doc/examples/livegrep/server.json for an example, and server/config/config.go for documentation of available options.

By default, livegrep will connect to a single local codesearch instance on port 9999, and listen for HTTP connections on port 8910.

github integration

livegrep includes a helper driver, livegrep-github-reindex, which can automatically update and index selected github repositories. To download and index all of my repositories (except for forks), storing the repos in repos/ and writing nelhage.idx, you might run:

bazel-bin/cmd/livegrep-github-reindex/livegrep-github-reindex -user=nelhage -forks=false -name=github.com/nelhage -out nelhage.idx

You can now use nelhage.idx as an argument to codesearch -load_index.

Local repository browser

livegrep provides the ability to view source files directly in livegrep, as an alternative to linking files to external viewers. This was initially implemented by @jboning here. There are a few ways to enable this. The most important steps are to

1. Generate a config file that livegrep can use to figure out where your source files are (locally).
2. Pass this config file as an argument to the frontend (-index-config)

Generating index manually

See doc/examples/livegrep/server.json for an example config file, and server/config/config.go for documentation on available options. To enable the file viewer, you must include an IndexConfig block inside of the config file. An example IndexConfig block can be seen at doc/examples/livegrep/index.json.

Tip: For each repository included in your IndexConfig, make sure to include metadata.url_pattern if you would like the file viewer to be able to link out to the external host. You'll see a warning in your browser console if you don't do this.

Generating index with livegrep-github-reindex

If you are already using the livegrep-github-reindex tool, an IndexConfig index file is generated for you, by default named "livegrep.json".

Run the indexer

bazel-bin/cmd/livegrep-github-reindex/livegrep-github-reindex_/livegrep-github-reindex -user=xvandish -forks=false -name=github.com/xvandish -out xvandish.idx ```

The indexer will have done these main things:

1. Clone (or update) all repositories for user=xvandish to/in repos/xvandish
2. Create an IndexConfig file - repos/livegrep.json
3. Create a code index, this is whats used to search - ./xvandish.idx

Here's an abbreviated version of what your directory might look like after running the indexer.

livegrep
│   xvandish.idx
└───repos
│   │   livegrep.json
│   └───xvandish
│       └───repo1
│       └───repo2
│       └───repo3

Using your generated index

Now that you generated an index file, it's time to run livegrep with it.

Run the backend:

bazel-bin/src/tools/codesearch -load_index xvandish.idx -grpc localhost:9999

Run the frontend in another shell instance with the path to the index file located at repos/livegrep.json.

bazel-bin/cmd/livegrep/livegrep_/livegrep -index-config ./repos/livegrep.json

In a browser, now visit http://localhost:8910 and you should see a working livegrep. Search for something, and once you get a result, click on the file name or a line number. You should now be taken to the file browser!

Docker images

Livegrep's CI builds Docker images into the livegrep organization docker repository on every merge to main. They should be generally usable. For instance, to build+run a livegrep index of this repository, you could run:

docker run -v $(pwd):/data ghcr.io/livegrep/livegrep/indexer /livegrep/bin/livegrep-github-reindex -repo livegrep/livegrep -http -dir /data
docker network create livegrep
docker run -d --rm -v $(pwd):/data --network livegrep --name livegrep-backend ghcr.io/livegrep/livegrep/base /livegrep/bin/codesearch -load_index /data/livegrep.idx -grpc 0.0.0.0:9999
docker run -d --rm --network livegrep --publish 8910:8910 ghcr.io/livegrep/livegrep/base /livegrep/bin/livegrep -docroot /livegrep/web -listen=0.0.0.0:8910 --connect livegrep-backend:9999

And then access http://localhost:8910/

You can also find the docker-compose config powering livegrep.com in the livegrep/livegrep.com repository.

Resource Usage

livegrep builds an index file of your source code, and then works entirely out of that index, with no further access to the original git repositories.

The index file will vary somewhat in size, but will usually be 3-5x the size of the indexed text. livegrep memory-maps the index file into RAM, so it can work out of index files larger than (available) RAM, but will perform better if the file can be loaded entirely into memory. Barring that, keeping the disk on fast SSDs is recommended for optimal performance.

Regex Support

Livegrep uses Google's re2 regular expression engine, and inherits its supported syntax.

RE2 is mostly PCRE-compatible, but with some mostly-deliberate exceptions

LICENSE

Livegrep is open source. See COPYING for more information.