Glossary of Terms

Event

All data passing through the Dispatch is in the form of events.

An Event has the following properties:

• id
• namespace/name - fully qualified name of the event type (kind). There will probably be a few globally defined, like errors
• timestamp
• source, which can be
  • function invocation (ref) - if the event's payload is a function return value/object (if any)
  • direct - if the event was created directly using the API
• data - the event payload, can be empty

Function

Functions are the application code that is deployed onto the Dispatch by developers (the primary users).

A Function has the following properties:

• id (unique, even across versions of the same entity)
• namespace/name
• version
• base image (ref)
• input schema (ref)
• output schema (ref)
• impl - (TBD) reference to the function implementation (source code, JAR, etc.)

Base Image

Base Image is a container image into which the function code gets injected at deploy time.

A Base Image has the following properties:

• id (unique, even across versions of the same entity)
• namespace/name
• version
• ... TBD

Invocation

An Invocation is a record that represents a single invocation of a Function on Dispatch.

An Invocation has the following properties:

• id
• function (ref)
• timestamp
• input event (ref) - the source event payload is the function argument
• state records - an ordered (by timestamp) list of the invocation states filled as the invocation progresses. A single state record contains:
  • timestamp
  • state - one of the following (incomplete) list:
    • validation-input
    • input-error:
      • input-invalid
    • running
    • validation-output
    • runtime-error:
      • internal-error
      • output-invalid
      • timed-out
    • success
• output event (ref) - on the function termination (successful or not), ref to the output (result/error) event

Schema

A schema is a formal definition of a type of data objects to be used as event payloads.

A schema has the following properties:

• id (unique, even across versions of the same entity)
• namespace/name
• version
• data - the schema data (can be represented in JSON or YAML)