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lsif

README.md

LSIF code intelligence

LSIF is a file format that stores code intelligence information such as hover docstrings, definitions, and references.

Sourcegraph receives LSIF data via src-cli, usually from a build running within CI, then uses that information to provide fast and precise code intelligence when viewing files.

The HTTP server runs behind Sourcegraph (for auth) and services requests for relevant LSP queries. LSIF dump uploads received by the server are stored in a temporary file to be asynchronously processed by the worker. The server and worker communicate via node-resque, a work broker powered by Redis.

Usage documentation

See the usage documentation on Sourcegraph.com.

Database Configuration

The LSIF processes store most of its data in SQLite repositories on a shared disk that are written once by a worker on LSIF dump upload, and read many times by the APIs to answer LSIF/LSP queries. Cross-repository and commit graph data is stored in Postgres, as this database requires many concurrent writers (which is an unsafe operation for SQLite in a networked application). The LSIF processes retrieve PostgreSQL connection configuration from the frontend process on startup.

We rely on the Sourcegraph frontend to apply our DB migrations. These live in the /migrations folder. This means:

  • The server and worker wait for the frontend to apply the migration version it cares about before starting.
  • We (and more importantly, site admins) only have to care about a single set of DB schema migrations. This is the primary property we benefit from by doing this.

Migrations

To add a new migration for the tables used by the LSIF processes, create a new migration in the frontend according to the instructions in the migration documentation. Then, update the value of MINIMUM_MIGRATION_VERSION in connection.ts to be the timestamp from the generated filename.

API

/upload

Receives an LSIF dump encoded as JSON lines.

URL query parameters:

  • repository: the name of the repository (e.g. github.com/sourcegraph/codeintellify)
  • commit: the 40 character hash of the commit

The request body must be HTML form data with a single file (e.g. curl -F "[email protected]" ...).

/request

Performs a hover, a definitions, or a references request for the given repository@commit and returns the result. Fails if there is no LSIF data for the given repository@commit.

The request body must be a JSON object with these properties:

  • repository: the name of the repository (e.g. github.com/sourcegraph/codeintellify)
  • commit: the 40 character hash of the commit
  • method: hover, definitions, or references
  • path: the file path in the repository.
  • position: the zero-based { line, character } in the file at which the request is being made

Service documentation

See the docs/ directory.