GitLab Sourcegraph integration

We'd like to have search across all our packages and all our GitLab projects (GitLab advanced search is tracked in #159 (closed)). One of the more advanced options out there would be sourcegraph which provides both, a free basic community version as well as an advanced enterprise version.

• example search: https://sourcegraph.com/search
• Tour: https://docs.sourcegraph.com/getting-started/tour

sourcegraph.com Features:

• Use regular expressions and exact queries to perform full-text searches.
• Perform language-aware structural search on code structure.
• Search any branch and commit, with no indexing required.
• Search commit diffs and commit messages to see how code has changed.
• Narrow your search by repository and file pattern.
• Smart Search query assistant.
• Use search contexts to search across a set of repositories at specific revisions.
• Curate saved searches for yourself or your org.
• Use code monitoring to set up notifications for code changes that match a query.
• View language statistics for search results.

Tasks

• investigate into sourcegraph and its setup plus peak into the enterprise features.
• If we are happy about that solution, the PL should reach out to sourcegraph and try to secure some sponsoring.
  • https://about.sourcegraph.com/pricing

While gitlab can integrate with sourcegraph, it can't use it for its advanced search. That still requires elastisearch. Running an elasticsearch instance in a container shouldn't be too hard, especially since we don't necessarily need to back it up as the data can be rebuilt.

I think sourcegraph should only be considered in addition.

changed title from Advanced GitLab code search to GitLab Sourcegraph integration

changed the description

GitLab is working on Exact Code Search which is powered by Zoekt. Zoekt is maintained by Sourcegraph.

Perhaps this could fulfill our needs? Unfortunately this is months away.