Installation(MAC)

Run EventStoreDB and PostgreSQL

docker-compose up -d 

Run Application

cargo run --bin web

• Install sqlx-cli

cargo install sqlx-cli

• To migrate, run below command

cargo sqlx migrate run --database-url postgres://frustacean:abc123@localhost:5434/community

• After adding queries, run below command

cargo sqlx prepare --database-url postgres://frustacean:abc123@localhost:5434/community 

EventStoreDB Admin UI

• Admin UI

Snapshoting

• EventStoreDB doesn't support snapshotting.

How to implement snapshoting

1. Events are appended to the stream post-123
2. Every nth event, a snapshot is appended to the stream e.g. post_snapshot-123
   • use _ instead of - in the suffix _snapshot, - is used by the system projection
3. Read backwards a single result from post_snapshot-123 stream

   ReadStreamOptions options = ReadStreamOptions.get()
       .backwards()
       .fromEnd();
   
   ReadResult result = client.readStream("post_snapshot-123", 1 /*maxCount*/, options)
       .get();
   
   List<ResolvedEvent> events = result.getEvents();

4. Read forwards from nth revisino from post-123 stream

   ReadStreamOptions options = ReadStreamOptions.get()
       .forwards()
       .fromRevision(n);
   
   ReadResult result = client.readStream("post-123", options)
       .get();
   
   List<ResolvedEvent> events = result.getEvents();

Links

• Event Sourcing with EventStoreDB
• EventStoreDB Rust Client