Replication

What is Replication?

Replication is the process of copying scheduled content and assets from a source to a destination. It is used to:

• Sync assets across environments (e.g., staging → production)
• Share scheduled content between different apps or websites
• Propagate changes from a master app to child apps on a schedule

What Gets Replicated

Data Type	Path	Notes
Scheduled Content	apps/{source}/banners → apps/{destination}/banners	All scheduled content or a single item
Assets	apps/{source}/contents → apps/{destination}/contents	All assets

Replication performs a direct copy; existing scheduled content and assets at the destination are overwritten with source data.

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Replication Types

1. Manual Replication

A user creates a replication record specifying source, destination, and optionally a single bannerId. The record is stored and triggers execution via Cloud Tasks.

• Full replication: No bannerId → copies all scheduled content and all assets
• Single scheduled content replication: bannerId set → copies only that item and all assets

2. Scheduled Replication

A replication can have a schedule (Unix timestamp). If the schedule is in the future, the job is queued via Cloud Tasks to run at that time. If the schedule is in the past or omitted, execution starts immediately.

3. Automated (Mass) Replication

Automated replication uses:

• massReplication config – Stored at apps/{appId}/config/massReplication. Includes enabled, emails (for notifications), and createdBy.
• autoReplication queue – Stored at apps/{appId}/autoReplication. Each entry references a scheduled content ID to replicate to a destination.
• Daily schedule – A Cloud Task is created to run at a configured time each day and replicate only the scheduled content listed in autoReplication.

When scheduled content is added to autoReplication, it is picked up by the next scheduled run. After replication, those entries are removed from the queue.

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Replication Lifecycle

Statuses

Status	Meaning
Pending	Replication created; Cloud Task queued or scheduled
In Progress	Replication job is running
Successful	Replication completed without errors
Error	Replication failed (see statusMessages)

Flow

1. Create – A replication record is written to replications/{id}.
2. Queue – Firebase trigger (onUpdateReplication or creation handler) creates a Cloud Task.
3. Run – replicationCallback or bannersAutoReplicator HTTP function executes.
4. Copy – Scheduled content and assets are read from source and written to destination in chunks.
5. Publish – After success, scheduled content is published to R2 for both source and destination apps.
6. Complete – Replication record is updated with status, completedAt, replicatedBannerIds, replicatedContentIds, etc.

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Web vs App: Base URL Replacement

When both source and destination are web apps:

• The system fetches baseUrl from apps/{appId}/config/consumer/baseUrl for both apps.
• Before copying, it replaces the source origin with the destination origin in:
  • banner.location
  • banner.locations (array)
  • banner.variants[].location
  • banner.variants[].locations (arrays)

This ensures embedded URLs in scheduled content point to the correct site after replication. If either base URL is missing, the replication records an error.

For app-to-app or mixed web/app replications, no URL replacement is performed.

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Data Model

Replication Record

Stored at replications/{id}:

Field	Type	Description
source	string	Source app ID
destination	string	Destination app ID
bannerId	string (optional)	Single scheduled content item to replicate; omit for full copy
status	enum	Pending, In Progress, Successful, Error
statusMessages	string[]	Error details when status is Error
schedule	number (optional)	Unix timestamp for scheduled run
automated	boolean	true for mass/auto replication
replicationTask	string (optional)	Cloud Task name
completedAt	number (optional)	Unix timestamp when finished
replicatedBannerIds	string[]	IDs of replicated scheduled content
replicatedContentIds	string[]	IDs of replicated assets
archived	boolean	Soft-delete flag
deleted	boolean	Soft-delete flag
createdAt, updatedAt	number	Timestamps
createdBy, updatedBy	string/object	User info

Source and Destination

Source and destination must be different apps. Replicating an app to itself is rejected with an error.

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Webhooks and Hooks

Replication Webhook

Configure a URL at apps/{appId}/config/webhooks.replicationWebhook. It receives HTTP POST requests when:

Operation	When
started	Replication job has started
completed	Replication job completed successfully
failed	Replication job failed

Payload includes replicationId, source, destination, status, bannerId, automated, schedule, and related metadata.

Client Hooks

These run in the Visual Experience Engine UI around scheduled content replication:

Hook	When
bannersReplicationBefore	Before replication runs
bannersReplicationAfter	After replication completes

These hooks are client-side and can be used to purge CDN cache, trigger analytics, etc.

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Technical Implementation

Cloud Tasks

• Replications are executed via Google Cloud Tasks.
• Non-automated replications: onUpdateReplication listens to replications/{id} and creates/updates Cloud Tasks when a replication record is created or changed.
• Automated replications: A daily task is created based on schedule and calls bannersAutoReplicator.

Concurrency

Only one replication runs at a time. If another replication is already executing, new ones are rescheduled 5–10 minutes later. After a maximum retry count, the replication is marked as Error.

Chunking

Firebase limits multi-path writes. Replication writes data in chunks (default 50 paths per update) to stay within limits.

R2 Publishing

After a successful replication, the system publishes scheduled content to R2 for both source and destination apps via the standard scheduled content publish pipeline. Results are stored on the replication record (publishResults, publishError, publishedAt).

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Summary

Concept	Description
Purpose	Copy scheduled content and assets from source app to destination app
Full vs single	Omit bannerId for all; set bannerId for one item
Manual vs automated	Manual = user-initiated; automated = daily mass replication via autoReplication queue
Web URL swap	For web→web, origins in URLs are replaced with destination base URL
Execution	Cloud Tasks invoke HTTP functions; Firebase triggers create tasks on record changes
Post-replication	Scheduled content is published to R2 for both apps