Accord

Fast and efficient coordination of distributed processes. Server and client implementation in Go on top of the gRPC framework.

Use Case

Imagine you are processing files within a directory or bucket, you would want to coordinate your workers to pick a file each, lock it for the duration of the processing and then mark it as done once finished so it's not picked up by another worker again.

Architecture

+------------+         +------------+     +--------------+
|            |         |            |     |              |
|   WORKER   | -gRPC-> |   SERVER   | --> |   BACKEND    |
|   Client   | <------ |            | <-- |  PostgreSQL  |
|            |         |            |     |              |
+------------+         +------------+     +--------------+

• Clients are connected to (a cluster of) Accord Servers and communicate via gRPC.
• Servers are using a pluggable backend (currently, PostgreSQL only) to coordinate state.
• Clients maintain a local state cache to avoid hammering the server/backends.

Documentation

Please see the API documentation for package and API descriptions and examples.

Backends

• PostgreSQL - requires version >= 9.5.
• Mock - in-memory backend, for testing only.
• Direct - direct allows to connect clients directy a backend, bypassing the server. Use at your own risk!