lib/connections: Add syncthing_connections_active metric (fixes #9527) (#9528)

### Purpose

Adds a new metric `syncthing_connections_active` which equals to the
amount of active connections per device.

Fixes #9527 

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### Testing

I've manually tested it by running syncthing with these changes locally
and examining the returned metrics from `/metrics`.
I've done the following things:
- Connect & disconnect a device
- Increase & decrease the number of connections and verify that the
value of the metric matches with the amount displayed in the GUI.

### Documentation

https://github.com/syncthing/docs/blob/main/includes/metrics-list.rst
needs to be regenerated with
[find-metrics.go](https://github.com/syncthing/docs/blob/main/_script/find-metrics/find-metrics.go)

## Authorship

Your name and email will be added automatically to the AUTHORS file
based on the commit metadata.

---------

Co-authored-by: Jakob Borg <jakob@kastelo.net>
This commit is contained in:
DerRockWolf 2024-05-04 22:31:37 +02:00 committed by GitHub
parent ec3e474a53
commit debbe726e0
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GPG Key ID: B5690EEEBB952194
3 changed files with 37 additions and 0 deletions

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@ -0,0 +1,27 @@
// Copyright (C) 2024 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package connections
import (
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
)
var (
metricDeviceActiveConnections = promauto.NewGaugeVec(prometheus.GaugeOpts{
Namespace: "syncthing",
Subsystem: "connections",
Name: "active",
Help: "Number of currently active connections, per device. If value is 0, the device is disconnected.",
}, []string{"device"})
)
func registerDeviceMetrics(deviceID string) {
// Register metrics for this device, so that counters & gauges are present even
// when zero.
metricDeviceActiveConnections.WithLabelValues(deviceID)
}

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@ -846,6 +846,7 @@ func (s *service) CommitConfiguration(from, to config.Configuration) bool {
newDevices := make(map[protocol.DeviceID]bool, len(to.Devices))
for _, dev := range to.Devices {
newDevices[dev.DeviceID] = true
registerDeviceMetrics(dev.DeviceID.String())
}
for _, dev := range from.Devices {
@ -853,6 +854,7 @@ func (s *service) CommitConfiguration(from, to config.Configuration) bool {
warningLimitersMut.Lock()
delete(warningLimiters, dev.DeviceID)
warningLimitersMut.Unlock()
metricDeviceActiveConnections.DeleteLabelValues(dev.DeviceID.String())
}
}
@ -1378,6 +1380,9 @@ func (c *deviceConnectionTracker) accountAddedConnection(conn protocol.Connectio
c.wantConnections[d] = int(h.NumConnections)
l.Debugf("Added connection for %s (now %d), they want %d connections", d.Short(), len(c.connections[d]), h.NumConnections)
// Update active connections metric
metricDeviceActiveConnections.WithLabelValues(d.String()).Inc()
// Close any connections we no longer want to retain.
c.closeWorsePriorityConnectionsLocked(d, conn.Priority()-upgradeThreshold)
}
@ -1399,6 +1404,10 @@ func (c *deviceConnectionTracker) accountRemovedConnection(conn protocol.Connect
delete(c.connections, d)
delete(c.wantConnections, d)
}
// Update active connections metric
metricDeviceActiveConnections.WithLabelValues(d.String()).Dec()
l.Debugf("Removed connection for %s (now %d)", d.Short(), c.connections[d])
}

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@ -58,5 +58,6 @@ func registerDeviceMetrics(deviceID string) {
metricDeviceSentUncompressedBytes.WithLabelValues(deviceID)
metricDeviceSentMessages.WithLabelValues(deviceID)
metricDeviceRecvBytes.WithLabelValues(deviceID)
metricDeviceRecvDecompressedBytes.WithLabelValues(deviceID)
metricDeviceRecvMessages.WithLabelValues(deviceID)
}