Technical Specification - Granular Data Retention

Summary

Adds the ability to configure custom (granular) deletion policies for posts for specific teams and/or channels. When the daily retention job runs it selectively deletes posts by age based on the configuration.

The granular policies completely override the global setting.

The feature requires some new APIs, some new tables, and an edit to the existing data retention job logic.

API

Global Policy (existing API)

GET /api/v4/data_retention/policy retrieves the global retention settings.

{
    "message_deletion_enabled": false,
    "file_deletion_enabled": false,
    "message_retention_cutoff": 0,
    "file_retention_cutoff": 0
}

The JSON object reflects the fields in the DataRetentionSettings config object for:

EnableMessageDeletion
EnableFileDeletion
MessageRetentionDays
FileRetentionDays

Updates to the global retention policy continues to be managed via the config APIs.

Retention Policies

POST /api/v4/retention_policies create a new retention policy.

Request:

{
    "display_name": "foo",
    "post_duration": 4
}

201 response:

{
    "id": "m8zoumpj9pn9zexospoxi5dzoc",
    "display_name": "foo",
    "post_duration": 4
}

PUT /api/v4/retention_policies/:policy_id/patch patches a retention policy.

Request:

200 Response:

GET /api/v4/retention_policies/:policy_id gets a retention policy by id.

DELETE /api/v4/retention_policies/:policy_id deletes a retention policy.

Deleting a RetentionPolicies record also deletes all of the associated RetentionPoliciesChannels and RetentionPoliciesTeams records.

GET /api/v4/retention_policies lists all retention policies, including associated teams and channels.

Retention Policies Teams

POST /api/v4/retention_policies/:policy_id/teams associates a team to a retention policy.

Request:

Response:

Because a teams can only be associated to a single granular retention policy, we must specify which teams failed.

DELETE /api/v4/retention_policies/:policy_id/teams/:team_id removes a team from a retention policy.

Retention Policies Channels

POST /api/v4/retention_policies/:policy_id/channels associates a channel to a retention policy.

Request:

Response:

Because a channel can only be associated to a single granular retention policy, we must specify which channels failed.

DELETE /api/v4/retention_policies/:policy_id/channels/:channel_id deletes a channel from a retention policy.

Database

RetentionPolicies table

Column name	Description

Column name	Description
`Id`	varchar, primary key
`DisplayName`	varchar
`PostDuration`	int, the duration in days to keep posts

RetentionPoliciesChannels table

Column name	Description

Column name	Description
`PolicyId`	varchar, the RetentionPolicies.Id foreign key
`ChannelId`	varchar, the Channels.Id foreign key

TBD: Does ChannelId need to be indexed?

RetentionPoliciesTeams table

Column name	Description

Column name	Description
`PolicyId`	varchar, the RetentionPolicies.Id foreign key
`TeamId`	varchar, the Teams.Id foreign key

TBD: Does TeamId need to be indexed?

Model

Rename DataRetentionPolicy to GlobalDataRetentionPolicy
Add RetentionPolicy representing a record in the RetentionPolicies table.
Add RetentionPolicyChannel representing a record in the RetentionPoliciesChannels table.
Add RetentionPolicyTeam representing a record in the RetentionPoliciesTeams table.

Enterprise

Changes to various methods on DataRetentionWorker in data_retention/worker.go are required.

We need a new query to determine the Posts records to be deleted, the output of which can be a list of post ids to be used to delete Posts records and the following:

Reactions
Preferences (of Category ‘flagged_post’)
Threads
ThreadMemberships
LinkMetadata TBD: these aren’t currently purged via data retention, but they probably should be.

FileInfo (and their associated files on disk) and ChannelMemberHistory continue to be deleted system-wide with no new granularity.

TBD: Why is ChannelMemberHistory currently deleted as part of message retention days settings?

Mobile

No changes. Existing file-deleted and post-deleted UX covers all.