Adds a new subcomponent of the agent for queueing up logs until they can be sent over the Agent API.
Subsequent PR will change the agent to use this instead of the HTTP API for posting logs.
Relates to #10534
Fixes#12141Fixes#11750
PGCoord shutdown was uncoordinated, so an update at an inopportune time during shutdown would be rejected because the coordinator row was already deleted.
This PR ensures that the PGCoord subcomponents that write updates are shut down before we take down the heartbeats, which is responsible for deleting the coordinator row.
I noticed a possible race where tailnet.Conn can try to dial the embedded region before we've set our custom dialer that send the DERP in-memory. This closes that race and adds a test case for servertailnet with no STUN and an embedded relay
I think this will resolve#12136 but lets get a proper test at the system level before closing.
Before this change, we only register the node callback at start of day for the server tailnet. If the coordinator changes, like we know happens when we are licensed for the PGCoordinator, we close the connection to the old coord, and open a new one to the new coord.
The callback is designed to direct the updates to the new coordinator, but there is nothing that specifically triggers it to fire after we connect to the new coordinator.
If we have STUN, then period re-STUNs will generally get it to fire eventually, but without STUN it we could go indefinitely without a callback.
This PR changes the servertailnet to re-register the callback each time we reconnect to the coordinator. Registering a callback (even if it's the same callback) triggers an immediate call with our node information, so the new coordinator will have it.
Adds some debug endpoints for looking into the DERP server.
The `api/v2/debug/derp/traffic` endpoint requires the `ss` utility to be present in order to function. I have *not* added the `iproute2` package to our base image as it adds 11MB, so this endpoint won't be useful by default. However, in a debugging situation, we could exec into the container and then `apk add iproute2`, or build a special debug image.
The `api/v2/debug/expvar` handler contains DERP metrics as well as commandline and memstats.
Example:
```
{
"alert_failed": 0,
"alert_generated": 0,
"cmdline": ["/Users/spike/repos/coder/build/coder_darwin_arm64","--global-config","/Users/spike/repos/coder/.coderv2","server","--http-address","0.0.0.0:3000","--swagger-enable","--access-url","http://127.0.0.1:3000","--dangerous-allow-cors-requests=true"],
"derp": {"accepts": 1, "average_queue_duration_ms": 0, "bytes_received": 0, "bytes_sent": 0, "counter_packets_dropped_reason": {"gone_disconnected": 0, "gone_not_here": 0, "queue_head": 0, "queue_tail": 0, "unknown_dest": 0, "unknown_dest_on_fwd": 0, "write_error": 0}, "counter_packets_dropped_type": {"disco": 0, "other": 0}, "counter_packets_received_kind": {"disco": 0, "other": 0}, "counter_tcp_rtt": {}, "counter_total_dup_client_conns": 0, "gauge_clients_local": 1, "gauge_clients_remote": 0, "gauge_clients_total": 1, "gauge_current_connections": 1, "gauge_current_dup_client_conns": 0, "gauge_current_dup_client_keys": 0, "gauge_current_file_descriptors": 0, "gauge_current_home_connections": 1, "gauge_memstats_sys0": 20874504, "gauge_watchers": 0, "got_ping": 0, "home_moves_in": 0, "home_moves_out": 0, "multiforwarder_created": 0, "multiforwarder_deleted": 0, "packet_forwarder_delete_other_value": 0, "packets_dropped": 0, "packets_forwarded_in": 0, "packets_forwarded_out": 0, "packets_received": 0, "packets_sent": 0, "peer_gone_disconnected_frames": 0, "peer_gone_not_here_frames": 0, "sent_pong": 0, "unknown_frames": 0, "version": "1.47.0-dev20240214-t64db8c604"},
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"warning_failed": 0,
"warning_generated": 0
}
```
If we find the DERP metrics useful we could consider how to include them in Prometheus scrapes based on the tailnet `varz` package. That's for a later PR if at all.
Adds documentation on port requirements and a short overview of STUN with some example scenarios.
Co-authored-by: Dean Sheather <dean@deansheather.com>
Co-authored-by: Spike Curtis <spike@coder.com>
When we exceed the db-imposed limit of logs, we need to communicate that back to the agent. In v1 we did it with a 4xx-level HTTP status, but with dRPC, the errors are delivered as strings, which feels fragile to me for something we want to gracefully handle.
So, this PR adds the log limit exceeded as a field on the response message, and fixes the API handler to set it as appropriate instead of an error.
Spike Curtis