Developing campaigns

What are campaigns?

Before diving into the technical part of campaigns, make sure to read up on what campaigns are, what they're not and what we want them to be.

1. Start by looking at the campaigns description on about.sourcegraph.com.
2. Read through the campaigns documentation.
   • Especially: "Campaigns design doc" and "How src executes a campaign spec".

Starting up your environment

1. Run ./enterprise/dev/start.sh and wait until all repositories are cloned.
2. Create your first campaign. Remember: If you create a campaign, you're opening real PRs on GitHub. Make sure only testing repositories are affected. If you create a large campaign, it takes a while to preview/create but also helps a lot with finding bugs/errors, etc.

Glossary

The campaigns feature introduces a lot of new names, GraphQL queries and mutations and database tables. This section tries to explain the most common names and provide a mapping between the GraphQL types and their internal counterpart in the Go backend.

GraphQL type	Go type	Database table	Description
Campaign	campaigns.Campaign	campaigns	A campaign is a collection of changesets. The central entity.
ChangesetSpec	campaigns.ChangesetSpec	changeset_specs	A changeset spec describes the desired state of a changeset.
CampaignSpec	campaigns.CampaignSpec	campaign_specs	A campaign spec describes the desired state of a campaign.
ExternalChangeset	campaigns.Changeset	changesets	Changeset is the unified name for pull requests/merge requests/etc. on code hosts.
ChangesetEvent	campaigns.ChangesetEvent	changeset_events	A changeset event is an event on a code host, e.g. a comment or a review on a pull request on GitHub. They are created by syncing the changesets from the code host on a regular basis and by accepting webhook events and turning them into changeset events.

Database layout

Diving into the code as a backend developer

1. Read through ./cmd/frontend/graphqlbackend/campaigns.go to get an overview of the campaigns GraphQL API.
2. Read through ./internal/campaigns/*.go to see all campaigns-related type definitions.
3. Compare that with the GraphQL definitions in ./cmd/frontend/graphqlbackend/schema.graphql.
4. Start reading through ./enterprise/internal/campaigns/resolvers/resolver.go to see how the main mutations are implemented (look at CreateCampaign and ApplyCampaign to see how the two main operations are implemented).
5. Then start from the other end, enterprise/cmd/repo-updater/main.go. enterpriseInit() creates two sets of campaign goroutines:
6. campaigns.NewSyncRegistry creates a pool of syncers to pull changes from code hosts.
7. campaigns.RunWorkers creates a set of reconciler workers to push changes to code hosts as campaigns are applied.

GitHub testing account

Campaigns create changesets (PRs) on code hosts. If you are not part of the Sourcegraph organization, we recommend you create dummy projects to safely test changes on so you do not spam real repositories with your tests. If you are part of the Sourcegraph organization, we have an account set up for this purpose.

To use this account, follow these steps:

1. Find the GitHub sd9 user in 1Password
2. Copy the Campaigns Testing Token
3. Change your dev-private/enterprise/dev/external-services-config.json to only contain a GitHub config with the token, like this:

{
  "GITHUB": [
    {
      "authorization": {},
      "url": "https://github.com",
      "token": "<TOKEN>",
      "repositoryQuery": ["affiliated"]
    }
  ]
}