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Understanding commands

EventCatalog supports different message types, this includes commands, events (and soon queries).

Commands are messages that represent intent, commands can be rejected in distributed systems.

Example of a command

An example of a command would be PlaceOrder message over HTTP.

  • This message is used to place an order in a system
  • Commands can be rejected, the PlaceOrder may be rejected by the service that processes it.

Commands in EventCatalog

  • Commands in EventCatalog can be accepted by services or invoked by services.
  • Commands in EventCatalog are blue (following EventStorming conventions)
  • Commands live in the /commands folder.

Example