Datastream is a gRPC service definition that provides a consistent interface for requesting, propagating and receiving real-time data updates. It aims to be a simple interface for a common set of problems around use cases such as configuration management, real-time data such as exchange rates, notification subscribers, file management and similar.
ListCapabilities: lists available keys for subscriptionSync: sync with a server and receive the current stateSubscribe: subscribe to the data stream and receive updates, initially syncs all keysPushUpdate: if supported, update and push a value update back on the server
Note: Make sure you have installed protoc and the Go protobuf plugin on your system.
A storage interface and datastream grpc implementation example exists for
- git repository - key=file path, value=file content
- sqlite3 - key=table column, value=table column
- postgresql - key=table column, value=table column
- S3/minio compatible storage - key=path, valu=file content
There is also a freestanding settings server implementation example using
sqlite3 with a local gRPC service implementation under examples/server/ and a
self-communication example.
The example setting service shows how a datastream service can be used to requesting, subscribing and push updates.
make
./server &
./client &
./updater
kill %1 # also terminates the clientserver
2023/01/17 18:58:05 Starting gRPC server on :8080
2023/01/17 18:58:08 method: /datastream.DataService/ListCapabilities, duration: 190.625µs, error: <nil>
2023/01/17 18:58:12 method: /datastream.DataService/PushUpdate, duration: 1.05157ms, error: <nil>
client
2023/01/17 18:58:08 Capabilities: [key:"max_connections" value_type:"int" key:"rate_limit" value_type:"int" key:"debug_enabled" value_type:"bool"]
2023/01/17 18:58:08 Subscribing to key: max_connections
2023/01/17 18:58:08 Received update for key max_connections value [49 48], stringified data 10
2023/01/17 18:58:12 Received update for key max_connections value [50 48], stringified data 20