Exec server

Job protocol

A client runs a job on the execserver in two steps:

1. GET /token/{service} reserves a worker slot in the service's waitgroup. The response contains a one-time token, valid for 10 seconds. If all workers are busy, the execserver answers 503 All workers busy and the client retries once per second until its connect timeout is reached.

2. PUT /job/{service}?job={...} presents the token and runs the job. The token is held in memory by the instance that issued it, so this request must reach the same instance.

If tokenResponseSendServerIP is configured on the execserver, the token response also contains a service URL with the instance's own address. A client must then send the job request to that address. This is what makes running multiple load-balanced instances possible — see Scaling the execserver.

File Queue

Action: "metadata"

Runs fylr_metadata