Event sources¶
An event source is a Kubernetes custom resource (CR), created by a developer or cluster administrator, that acts as a link between an event producer and an event sink. A sink can be a k8s service, including Knative Services, a Channel, or a Broker that receives events from an event source.
Event sources are created by instantiating a CR from a Source object. The Source object defines the arguments and parameters needed to instantiate a CR.
All Sources are part of the sources category.
You can list existing event sources on your cluster by entering the kn command:
kn source list
You can list existing event sources on your cluster by entering the command:
kubectl get sources
Note
Event Sources that import events from other messaging technologies such as Kafka or RabbitMQ are not responsible for setting Optional Attributes such as the datacontenttype. This is a responsibility of the original event producer; the Source just appends attributes if they exist.
Knative Sources¶
| Name | API Version | Maintainer | Description |
|---|---|---|---|
| APIServerSource | v1 | Knative | Brings Kubernetes API server events into Knative. The APIServerSource fires a new event each time a Kubernetes resource is created, updated or deleted. |
| AWS SQS | v1alpha1 | Knative | Brings AWS Simple Queue Service messages into Knative. The AwsSqsSource fires a new event each time an event is published on an AWS SQS topic. |
| Apache Camel | N/A | Apache Software Foundation | Enables use of Apache Camel components for pushing events into Knative. Camel sources are now provided via Kamelets as part of the Apache Camel K project. |
| Apache CouchDB | v1alpha1 | Knative | Brings Apache CouchDB messages into Knative. |
| Apache Kafka | v1beta1 | Knative | Brings Apache Kafka messages into Knative. The KafkaSource reads events from an Apache Kafka Cluster, and passes these events to a sink so that they can be consumed. See the Kafka Source example for more details. |
| ContainerSource | v1 | Knative | The ContainerSource instantiates container image(s) that can generate events until the ContainerSource is deleted. This may be used, for example, to poll an FTP server for new files or generate events at a set time interval. Given a spec.template with at least a container image specified, the ContainerSource keeps a Pod running with the specified image(s). K_SINK (destination address) and KE_CE_OVERRIDES (JSON CloudEvents attributes) environment variables are injected into the running image(s). It is used by multiple other Sources as underlying infrastructure. Refer to the Container Source example for more details. |
| GitHub | v1alpha1 | Knative | Registers for events of the specified types on the specified GitHub organization or repository, and brings those events into Knative. The GitHubSource fires a new event for selected GitHub event types. See the GitHub Source example for more details. |
| GitLab | v1alpha1 | Knative | Registers for events of the specified types on the specified GitLab repository, and brings those events into Knative. The GitLabSource creates a webhooks for specified event types, listens for incoming events, and passes them to a consumer. See the GitLab Source example for more details. |
| Heartbeats | N/A | Knative | Uses an in-memory timer to produce events at the specified interval. |
| KogitoSource | v1alpha1 | Knative | An implementation of the Kogito Runtime custom resource managed by the Kogito Operator. |
| PingSource | v1beta2 | Knative | Produces events with a fixed payload on a specified Cron schedule. See the Ping Source example for more details. |
| RabbitMQ | Active development | Knative | Brings RabbitMQ messages into Knative. |
| SinkBinding | v1 | Knative | The SinkBinding can be used to author new event sources using any of the familiar compute abstractions that Kubernetes makes available (e.g. Deployment, Job, DaemonSet, StatefulSet), or Knative abstractions (e.g. Service, Configuration). SinkBinding provides a framework for injecting K_SINK (destination address) and K_CE_OVERRIDES (JSON cloudevents attributes) environment variables into any Kubernetes resource which has a spec.template that looks like a Pod (aka PodSpecable). See the SinkBinding example for more details. |
| WebSocket | N/A | Knative | Opens a WebSocket to the specified source and packages each received message as a Knative event. |
Third-Party Sources¶
| Name | API Version | Maintainer | Description |
|---|---|---|---|
| Amazon CloudWatch | Supported | TriggerMesh | Collects metrics from Amazon CloudWatch. (installation) (example) |
| Amazon CloudWatch Logs | Supported | TriggerMesh | Subscribes to log events from an Amazon CloudWatch Logs stream. (installation) (example) |
| AWS CodeCommit | Supported | TriggerMesh | Registers for events emitted by an AWS CodeCommit source code repository. (installation) (example) |
| Amazon Cognito Identity | Supported | TriggerMesh | Registers for events from Amazon Cognito identity pools. (installation) (example) |
| Amazon Cognito User | Supported | TriggerMesh | Registers for events from Amazon Cognito user pools. (installation) (example) |
| Amazon DynamoDB | Supported | TriggerMesh | Reads records from an Amazon DynamoDB stream. (installation) (example) |
| Amazon Kinesis | Supported | TriggerMesh | Reads records from an Amazon Kinesis stream. (installation) (example) |
| Amazon RDS Performance Insights | Supported | TriggerMesh | Subscribes to metrics from Amazon RDS Performance Insights. (installation) (example) |
| Amazon S3 | Supported | TriggerMesh | Subscribes to event notifications from an Amazon S3 bucket. (installation) (example) |
| Amazon SNS | Supported | TriggerMesh | Subscribes to messages from an Amazon SNS topic. (installation) (example) |
| Amazon SQS | Supported | TriggerMesh | Consumes messages from an Amazon SQS queue. (installation) (example) |
| Auto Container Source | Proof of Concept | None | AutoContainerSource is a controller that allows the Source CRDs without needing a controller. It notices CRDs with a specific label and starts controlling resources of that type. It utilizes Container Source as underlying infrastructure. |
| Azure Activity Logs | Supported | TriggerMesh | Capture activity logs from Azure Activity Logs. (installation) (example) |
| Azure Blob Storage | Supported | TriggerMesh | Subscribes to events from an Azure Blob Storage account. (installation) (example) |
| Azure Event Grid | Supported | TriggerMesh | Retrieves events from Azure Event Grid. (installation) (example) |
| Azure Event Hubs | Supported | TriggerMesh | Consumes events from Azure Event Hubs. (installation) (example) |
| Azure IoT Hub | Supported | TriggerMesh | Consumes event from Azure IoT Hub. (installation) (example) |
| Azure Queue Storage | Supported | TriggerMesh | Retrieves messages from Azure Queue Storage. (installation) (example) |
| Azure Service Bus Queues | Supported | TriggerMesh | Consumes messages from an Azure Service Bus queue. (installation) (example) |
| Azure Service Bus Topics | Supported | TriggerMesh | Subscribes to messages from an Azure Service Bus topic. (installation) (example) |
| BitBucket | Proof of Concept | None | Registers for events of the specified types on the specified BitBucket organization/repository. Brings those events into Knative. |
| CloudAuditLogsSource | v1 | Registers for events of the specified types on the specified Google Cloud Audit Logs. Brings those events into Knative. Refer to the CloudAuditLogsSource example for more details. | |
| CloudPubSubSource | v1 | Brings Cloud Pub/Sub messages into Knative. The CloudPubSubSource fires a new event each time a message is published on a Google Cloud Platform PubSub topic. See the CloudPubSubSource example for more details. | |
| CloudSchedulerSource | v1 | Create, update, and delete Google Cloud Scheduler Jobs. When those jobs are triggered, receive the event inside Knative. See the CloudSchedulerSource example for further details. | |
| CloudStorageSource | v1 | Registers for events of the specified types on the specified Google Cloud Storage bucket and optional object prefix. Brings those events into Knative. See the CloudStorageSource example. | |
| Direktiv | Proof of concept | Direktiv | Receive events from Direktiv. |
| DockerHubSource | v1alpha1 | None | Retrieves events from Docker Hub Webhooks and transforms them into CloudEvents for consumption in Knative. |
| FTP / SFTP | Proof of concept | None | Watches for files being uploaded into a FTP/SFTP and generates events for those. |
| GitHub Issue Comments | Proof of Concept | None | Polls a specific GitHub issue for new comments. |
| Google Cloud Audit Logs | Supported | TriggerMesh | Captures audit logs from Google Cloud Audit Logs. (installation) (example) |
| Google Cloud Billing | Supported | TriggerMesh | Captures budget notifications from Google Cloud Billing. (installation) (example) |
| Google Cloud IoT | Supported | TriggerMesh | Subscribes to messages from a Google Cloud IoT registry. (installation) (example) |
| Google Cloud Pub/Sub | Supported | TriggerMesh | Subscribes to messages from a Google Cloud Pub/Sub topic. (installation) (example) |
| Google Cloud Source Repositories | Supported | TriggerMesh | Consumes events from Google Cloud Source Repositories. (installation) (example) |
| Google Cloud Storage | Supported | TriggerMesh | Captures change notifications from a Google Cloud Storage bucket. (installation) (example) |
| HTTP Poller | Supported | TriggerMesh | Periodically pulls events from an HTTP/S URL. (installation) (example) |
| Heartbeat | Proof of Concept | None | Uses an in-memory timer to produce events as the specified interval. Uses AutoContainerSource for underlying infrastructure. |
| K8s | Proof of Concept | None | Brings Kubernetes cluster events into Knative. Uses AutoContainerSource for underlying infrastructure. |
| Konnek | Active Development | None | Retrieves events from cloud platforms (like AWS and GCP) and transforms them into CloudEvents for consumption in Knative. |
| Oracle Cloud Infrastructure | Supported | TriggerMesh | Retrieves metrics from Oracle Cloud Infrastructure. (installation) (example) |
| RedisSource | v1alpha1 | None | Brings Redis Stream into Knative. |
| Salesforce | Supported | TriggerMesh | Consumes events from a Salesforce channel. (installation) (example) |
| Slack | Supported | TriggerMesh | Subscribes to events from Slack. (installation) (example) |
| SNMP | Proof of concept | Direktiv | Receive events via SNMP. |
| Twilio | Supported | TriggerMesh | Receive events from Twilio. (installation) (example) |
| VMware | Active Development | VMware | Brings vSphere events into Knative. |
| Webhook | Supported | TriggerMesh | Ingest events from a webhook using HTTP. (installation) (example) |
| Zendesk | Supported | TriggerMesh | Subscribes to events from Zendesk. (installation) (example) |
Additional resources¶
- If your code needs to send events as part of its business logic and doesn't fit the model of a Source, consider feeding events directly to a Broker.
- For more information about using
knSource related commands, see thekn sourcereference documentation.