#4679 [Core feature] Event Based Sensors for bucket upload events Issue created by ajbeach2 ### Motivation: Why do you think this is important? Processing files uploaded to GCS buckets and triggering processing based on the prefix is a common pattern. Different prefixs may trigger different workflows. Right now, the

FileSensor

supports bucket keys, but not prefixes. This use case is more generically a Pub/Sub sensor because typically you would configure the bucket to send a notification to a PubSub Topic based on the prefix. ### Goal: What should the final outcome look like, ideally? This feature would allow for triggering workflows from pub/sub topics. With this feature, it would be possible to setup workflows to be triggered by events from different prefixes in GCS buckets. ### Describe alternatives you've considered This use case can be satisfied by a custom Sensor class, or by having an external service that subscribes or polls events which triggers the workflows programmatically. These solutions are less convenient. ### Propose: Link/Inline OR Additional context The proposed solution is to create an PubSubSensor. There could also be an SQS or SNS sensor to support S3/AWS. A more generic class to support multiple topic/queue types my also be considered. ### Are you sure this issue hasn't been raised already? • Yes ### Have you read the Code of Conduct? • Yes flyteorg/flyte