item-service.md

Item Service

Manages the description and auction status (created, auction, completed, cancelled) of an item.

Commands handled

External (user)

• createItem - Creates an item - emits ItemUpdated.
• updateItem - Updates user editable properties of an item, if allowed in the current state (eg, currency can't be updated after auction is started), emits ItemUpdated.
• startAuction - Starts the auction if current state allows it, emits AuctionStarted.
• cancelAuction (not supported) - Cancels the auction if current state allows it, emits AuctionCancelled.

Queries handled

• getItem - Gets an item by an ID.
• getItemsForUser - Gets a list of items in a provided status that are owned by a given user.

Events emitted

• AuctionStarted (public) - When the auction is started, in response to startAuction.
• ItemUpdated (public) - When user editable fields on an item are updated in response to createItem or updateItem.
• AuctionCancelled (private) - When the auction is cancelled, in response to cancelAuction.
• AuctionFinished (public) - When the auction is finished, in response to BiddingFinished.

Event emitted publicly are published via a broker topic named item-ItemEvent.

Events consumed

• BidService.BidPlaced - on every accepted bid, Item service will update a copy of the price of the item. This is a denormalized field, Bid Service is the source of truth.
• BidService.BiddingFinished - when Bid Service notifies the auction is over, Item service updates it's copy of the final price and winner (if there was one).