Event sources

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

kubectl

You can list existing event sources on your cluster by entering the command:

kubectl get sources

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 will instantiate 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, ContainerSource will keep 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	None	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
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.
Amazon CloudWatch	Supported	TriggerMesh	Collects metrics from Amazon CloudWatch.
Amazon CloudWatch Logs	Supported	TriggerMesh	Subscribes to log events from an Amazon CloudWatch Logs stream.
Amazon CodeCommit	Supported	TriggerMesh	Registers for events emitted by an Amazon CodeCommit source code repository.
Amazon Cognito Identity	Supported	TriggerMesh	Registers for events from Amazon Cognito identity pools.
Amazon Cognito User	Supported	TriggerMesh	Registers for events from Amazon Cognito user pools.
Amazon DynamoDB	Supported	TriggerMesh	Reads records from an Amazon DynamoDB stream.
Amazon Kinesis	Supported	TriggerMesh	Reads records from an Amazon Kinesis stream.
Amazon SNS	Supported	TriggerMesh	Subscribes to messages from an Amazon SNS topic.
Amazon SQS	Supported	TriggerMesh	Consumes messages from an Amazon SQS queue.
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	Google	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	Google	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	Google	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	Google	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.
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.
Heartbeat	Proof of Concept	None	Uses an in-memory timer to produce events as the specified interval. 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.
K8s	Proof of Concept	None	Brings Kubernetes cluster events into Knative. Uses AutoContainerSource for underlying infrastructure.
RedisSource	v1alpha1	None	Brings Redis Stream into Knative.
Slack	v1alpha1	TriggerMesh	Subscribes to events from Slack.
VMware	Active Development	VMware	Brings vSphere events into Knative.
Zendesk	v1alpha1	TriggerMesh	Subscribes to events from Zendesk.

Additional resources

For information about creating your own Source type, see the tutorial on writing a Source with a Receive Adapter.
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 kn Source related commands, see the kn source reference documentation.