Using Perforce depots with Sourcegraph

Sourcegraph supports Perforce Helix depots using p4-fusion. This creates an equivalent Git repository from a Perforce depot, which can then be indexed by Sourcegraph.

Screenshot of a Perforce repository in a Sourcegraph

Configure experimental features

As of Sourcegraph 5.1, there are new features for Perforce depots that need to be enabled.

Changelist ID in URLs

Note: When enabling changelist IDs in URLs for the first time, Perforce depots can be unavailable for a few minutes on the Sourcegraph instance, due to the initial mapping of changelist IDs to generated commit ID happening in the background. If you have a large number of Perforce depots, we recommend proceeding with the following steps in a maintenance window in which you don't expect large amounts of traffic on your Sourcegraph instance.

Add "perforceChangelistMapping": "enabled", to experimentalFeatures in the site configuration:

{
  "experimentalFeatures": {
    "perforceChangelistMapping": "enabled"
  }
}

When enabled, URLs for Perforce code hosts will use the Changelist (CL) ID instead of commit SHAs. Areas that benefit from this at the moment are:

  • Viewing a specific CL
  • Viewing the files of a depot at a specific CL
  • Viewing a specific file added / removed / modified in a specific CL
  • Viewing the list of CLs

Limitations

  • After a depot is cloned or fetched, Sourcegraph computes and stores mappings of CL IDs to commit SHAs. This mapping can take several minutes for large clones/fetches. When a background mapping job is running, the depot won't be serviceable as URLs referring to CL IDs may not resolve and users may see an error while interacting with the depot.
  • This experimental configuration can not be selectively enabled for a specific perforce depot.

Mechanism

To support CLs natively in the URLs, Sourcegraph performs background computation after syncing the contents of a depot. That's done by parsing each generated commit to retrieve the corresponding CL ID and store it in the repo_commits_changelists table. This is currently performed on only one depot at a time and we are working to support this for multiple depots in parallel in an upcoming release.

Additionally, while removing a depot from a code host config will mark it as "deleted", the mapped information will not be deleted to prevent forced re-computation after an accidental removal of depot from a code host config. Similarly recloning a depot will not trigger a computation of all the CLs from the beginning of the depot's source control history. If site admins are recloning or deleting and re-adding a depot to Sourcegraph as a result of history rewrite of a depot in Perforce, they should get in touch with us for next steps.

Batch Changes support for Perforce depots

Add "batchChanges.enablePerforce": true to experimentalFeatures in the site configuration:

{
  "experimentalFeatures": {
   "batchChanges.enablePerforce": true,
  }
}

Batch Changes does not support repos that use sub-repo permissions, so in order to use batch changes with Perforce depots, the code host cannot use file-level permissions.

When a Batch Change is published, it is sent as a shelved changelist to the server configured in the code host. The Changelist Id is displayed in the UI for the user to use for managing the shelved changelist.

Add a Perforce code host connection

Perforce depots can be added to a Sourcegraph instance by adding the appropriate code host connection.

To enable Perforce code host connections, a site admin must:

  1. Go to Site admin > Manage code hosts > Add code host

  2. Scroll down the list of supported code hosts and select Perforce.

  3. Configure which depots are mirrored/synchronized as Git repositories to Sourcegraph:

    • depots

      A list of depot paths that can be either a depot root or an arbitrary subdirectory. Note: Only "local" type depots are supported.

    • p4.user

      The user to be authenticated for p4 CLI, and should be capable of performing:

      • p4 login
      • p4 trust
      • and any p4 commands involved with git p4 clone and git p4 sync for listed depots.

      If repository permissions are mirrored, the user needs additional ability (aka. "super" access level) to perform the commands:

      • p4 protects
      • p4 groups
      • p4 group
      • p4 users

    • p4.passwd

      The ticket to be used for authenticating the p4.user. It is recommended to create tickets of users in a group that never expire. Use the command p4 -u <p4.user> login -p -a to obtain a ticket value.

    • See the configuration documentation below for other fields you can configure.

  4. Configure fusionClient:

    {
  "fusionClient": {
    "enabled": true,
    "lookAhead": 2000
  }
}

    Details of all p4-fusion configuration fields can be seen here.

  5. Click Add repositories.

Sourcegraph will now talk to the Perforce host and sync the configured depots to the Sourcegraph instance.

It's worthwhile to note some limitations of this process:

  • When syncing depots either git p4 or p4-fusion (recommended) are used to convert Perforce depots into git repositories so that Sourcegraph can index them.
  • Rename of a Perforce depot, including changing the depot on the Perforce server or the repositoryPathPattern config option, will cause a re-import of the depot.
  • Unless permissions syncing is enabled, Sourcegraph is not aware of the depot permissions, so it can't enforce access restrictions.

Repository permissions

To enforce file-level permissions for Perforce depots using the Perforce protects file, include the authorization field in the configuration of the Perforce code host connection you created above:

{
  "authorization": {}
}

Adding the authorization field to the code host connection configuration will enable partial parsing of the protects file. Learn more about the partial support of protects file parsing.

Syncing subdirectories to match permission boundaries

By default Sourcegraph only supports repository-level permissions and does not match the granularity of the Perforce protects file.

If you don't activate file-level permissions you should sync subdirectories of a depot using the depots configuration that best describes the most concrete path of your permissions boundary.

For example, if your Perforce depot //depot/Talkhouse has different permissions for //depot/Talkhouse/main-dev and subdirectories //depot/Talkhouse/rel1.0/front, //depot/Talkhouse/rel1.0/back we recommend setting the following depots:

{
  "depots": [
    "//depot/Talkhouse/main-dev/",
    "//depot/Talkhouse/rel1.0/front/",
    "//depot/Talkhouse/rel1.0/back/"
  ]
}

By configuring each subdirectory that has unique permissions, Sourcegraph is able to recognize and enforce permissions for the sub-directories. You can NOT define these permissions as:

{
  "depots": [
    "//depot/Talkhouse/main-dev/",
    "//depot/Talkhouse/rel1.0/",
    "//depot/Talkhouse/rel1.0/back/"
  ]
}

Since that would override the permissions for the //depot/Talkhouse/rel1.0/back depot.

Wildcards

File-level permissions can handle wildcards in the protects file. If file-level permissions is not enabled, Sourcegraph provides limited support for * and ... paths, so the workaround of adding sub-folders as separate repositories for the paths that employ wildcards needs to be followed.

File-level permissions

File-level permissions make the syncing of subdirectories to match permission boundaries unnecessary.

To enable file-level permissions:

  1. Enable the feature in the site config:

    {
  "experimentalFeatures": {
    "subRepoPermissions": { "enabled": true }
  }
}

  2. Enable the feature in the code host configuration by adding subRepoPermissions to the authorization object:

    {
  "authorization": {
    "subRepoPermissions": true
  }
}

  3. Save the configuration. Permissions will be synced in the background based on your Perforce protects file.

Handling Host rules in the protects file

When file-level permissions are enabled, Sourcegraph will read the Perforce protects file to determine what users can access. Because Sourcegraph originates all depot access from one host, protects rules with a Host field cannot be followed exactly. By default, they are parsed as if they apply to all hosts, which can result in users losing access when they should have access. If you have protects rules with hosts that are causing lost access for users, you can set ignoreRulesWithHost to true in the code host configuration.

    {
      "authorization": {
        "subRepoPermissions": true,
        "ignoreRulesWithHost": true
      }
    }

Notes about permissions

  • Sourcegraph users are mapped to Perforce users based on their verified email addresses.
  • As long as a user has been granted at least Read permissions in Perforce they will be able to view content in Sourcegraph.
  • As a special case, commits in which a user does not have permissions to read any files are hidden. If a user can read a subset of files in a commit, only those files are shown.
  • The host field from protections are not supported.
  • file-level permissions must be disabled for Batch Changes to work.
  • Setting authz.enforceForSiteAdmins to true in the site configuration will enforce permissions for admin users. They may not be able to see repositories and their contents if their Sourcegraph user account email does not match with their email on the Perforce server.

Configuration

admin/external_service/perforce.schema.json 

{
	// If non-null, enforces Perforce depot permissions.
	"authorization": null,

	// Depots can have arbitrary paths, e.g. a path to depot root or a subdirectory.
	"depots": null,
	// Other example values:
	// - [
	//     "//Sourcegraph/",
	//     "//Engineering/Cloud/"
	//   ]

	// Configuration for the experimental p4-fusion client
	"fusionClient": null,

	// Only import at most n changes when possible (git p4 clone --max-changes).
	"maxChanges": 1000,

	// Client specified as an option for p4 CLI (P4CLIENT, also enables '--use-client-spec')
	"p4.client": null,

	// The ticket value for the user (P4PASSWD). You can get this by running `p4 login -p` or `p4 login -pa`. It should look like `6211C5E719EDE6925855039E8F5CC3D2`.
	"p4.passwd": null,

	// The Perforce Server address to be used for p4 CLI (P4PORT).
	"p4.port": null,
	// Other example values:
	// - "ssl:111.222.333.444:1666"

	// The user to be authenticated for p4 CLI (P4USER).
	"p4.user": null,
	// Other example values:
	// - "admin"

	// The pattern used to generate the corresponding Sourcegraph repository name for a Perforce depot. In the pattern, the variable "{depot}" is replaced with the Perforce depot's path.
	//
	// For example, if your Perforce depot path is "//Sourcegraph/" and your Sourcegraph URL is https://src.example.com, then a repositoryPathPattern of "perforce/{depot}" would mean that the Perforce depot is available on Sourcegraph at https://src.example.com/perforce/Sourcegraph.
	//
	// It is important that the Sourcegraph repository name generated with this pattern be unique to this Perforce Server. If different Perforce Servers generate repository names that collide, Sourcegraph's behavior is undefined.
	"repositoryPathPattern": "{depot}"
}

Known issues and limitations

We are actively working to significantly improve Sourcegraph's Perforce support. Please file an issue to help us prioritize any specific improvements you'd like to see.

  • Sourcegraph was initially built for Git repositories only, so it stores Perforce depots as Git repositories when syncing. Perforce concepts and languages are expressed in the UI, but under the hood, Git tools are used.
  • The host field in protections is not supported.
  • Batch Changes does not support file-level permissions (also known as sub-repo permissions)
  • Batch Changes does not handle the shelved changelist other than to query the Perforce server for its status.
  • Permalinks with Changelist Id do not work yet