The Oracle Cloud Infrastructure Notifications service broadcasts messages to distributed components through a publish-subscribe pattern, delivering secure, highly reliable, low latency and durable messages for applications hosted on Oracle Cloud Infrastructure and externally. Use Notifications to get notified when event rules are triggered or alarms are breached, or to directly publish a message.
How Notifications Works
The Notifications service enables you to set up communication channels for publishing messages using topics and subscriptions . When a message is published to a topic, the Notifications service sends the message to all of the topic's subscriptions.
When a subscriber’s endpoint does not acknowledge receipt of the message, the Notifications service retries delivery. This situation can occur when the endpoint is offline. For example, the email server for an email address may be down.
Notifications retries delivery following these steps until either (a) acknowledgement is received or (b) the subscription's retry duration is over. By default, the retry duration is two hours.
- Immediate retry.
- Exponential backoff retry for the period of the subscription's retry duration, using the following timing:
- 1 minute
- 2 minutes
- 4 minutes
- 8 minutes
- 16 minutes
- 32 minutes
- Discarding of the message at the end of the retry duration.
You can change the retry duration for a subscription. For instructions using the Console, see To update the retry duration for a subscription. For the API, use the following operation: UpdateSubscription.
The following concepts are essential to working with Notifications.
- The content that is published to a topic. Each message is delivered at least once per subscription. Every message sent out as email contains a link to unsubscribe from the related topic.
- An endpoint for a topic. Published messages are sent to each subscription for a topic. For supported subscription protocols, see To create a subscription.
- A communication channel for sending messages to the subscriptions in the topic. Each topic name is unique across the tenancy.
Messages sent out as email by the Oracle Cloud Infrastructure Notifications service are processed and delivered through Oracle resources in U.S.-based regions.
Flow of Message Publication
Notifications publishes messages when event rules are triggered, alarms are breached, or someone directly publishes a message.
Event rules: Notifications sends messages when rules are triggered. The message is sent to the topic specified in the rule. For example, a message might be configured for new databases. See Managing Rules for Events.
Alarms: Notifications sends alarm messages when alarms are breached. The alarm message is sent to the topic specified in the alarm. For example, an alarm message might be configured for high CPU usage. See Managing Alarms.
Direct publication: Notifications sends messages when you (or a service or app) publish the messages directly. The message is sent to the topic you specify. See Publishing Messages.
Service Comparison for Sending Email Messages
Consider the following service features when deciding whether to use the Notifications service or the Email Delivery service to send your email messages. For more information about Email Delivery, see Overview of the Email Delivery Service.
|Service Feature||Notifications service||Email Delivery service|
|Requires confirmation before sending email.||Yes||No|
|Allows email decorations, such as signatures.||Yes||No|
|Allows raw email messages.||No||Yes|
|Supports MIME attachments.||No||
|Supports special handling for failed email delivery.||No||
|Priced for small messages (less than 32 KB, with a 64-KB limit).||Yes||No|
|Priced for large messages (greater than 32 KB, with a 2-MB limit).||No||Yes|
Most types of Oracle Cloud Infrastructure resources have a unique, Oracle-assigned identifier called an Oracle Cloud ID (OCID). For information about the OCID format and other ways to identify your resources, see Resource Identifiers.
Moving Topics and Subscriptions to a Different Compartment
You can move topics and subscriptions from one compartment to another. When you move a topic to a new compartment, its associated subscriptions remain in their existing compartment. The same consideration applies when moving a subscription: its associated topic remains in its existing compartment.
After you move the topic or subscription to the new compartment, inherent policies apply immediately and affect access to the moved topic or subscription through the Console. For more information, see To move a resource to a different compartment.
To move resources between compartments, resource users must have sufficient access permissions on the compartment that the resource is being moved to, as well as the current compartment. For more information about permissions for Notifications resources, see Details for the Notifications Service.
Ways to Access Notifications
You can access the Notifications service using the Console (a browser-based interface) or the REST API. Instructions for the Console and API are included in topics throughout this guide. For a list of available SDKs, see Software Development Kits and Command Line Interface.
Console: To access Notifications using the Console, you must use a supported browser. You can use the Console link at the top of this page to go to the sign-in page. You will be prompted to enter your cloud tenant, your user name, and your password. Open the navigation menu. Under Solutions and Platform, go to Application Integration and click Notifications.
API: To access Notifications through API, use Notifications API.
Authentication and Authorization
Each service in Oracle Cloud Infrastructure integrates with IAM for authentication and authorization, for all interfaces (the Console, SDK or CLI, and REST API).
An administrator in your organization needs to set up groups , compartments , and policies that control which users can access which services, which resources, and the type of access. For example, the policies control who can create new users, create and manage the cloud network, launch instances, create buckets, download objects, etc. For more information, see Getting Started with Policies. For specific details about writing policies for each of the different services, see Policy Reference.
If you’re a regular user (not an administrator) who needs to use the Oracle Cloud Infrastructure resources that your company owns, contact your administrator to set up a user ID for you. The administrator can confirm which compartment or compartments you should be using.
Administrators: For common policies that give groups access to Notifications, see Allow a group to manage topics, Allow a group to manage topic subscriptions, and Allow a group to publish messages to topics.
Limits on Notifications
See Service Limits for a list of applicable limits and instructions for requesting a limit increase. To set compartment-specific limits on a resource or resource family, administrators can use compartment quotas.
Limits for publishing messages (PublishMessage operation)
All limits are per tenancy.
|Limit type||Limit amount|
|Message size per request||64KB|
|Message delivery rate per endpoint for HTTP-based protocols (endpoints that begin with "http:" or "https:")||60 messages per minute|
|Message delivery rate per endpoint for Email protocol||10 messages per minute|
|Messages per minute (also known as Transactions Per Minute, or TPM)||60 per topic|