duplicate metrics collector registration panic when using remotecfg

[tpaschalis]

What's wrong?

I ran Alloy with the remotecfg block and got a panic: duplicate metrics collector registration attempted

Steps to reproduce

Not sure yet, will update the issue accordingly.

System information

macOS

Software version

Grafana Alloy v1.5.1

Configuration

remotecfg {
	url            = "URL"
	id             = sys.env("GCLOUD_FM_COLLECTOR_ID")
	poll_frequency = "60s"

	basic_auth {
		username = "USER"
		password = "PASS"
	}
}

Logs

ts=2025-02-21T10:29:28.28662Z level=info msg="finished complete graph evaluation" controller_path=/ controller_id=remotecfg trace_id=bc9d6fe592c45275f8fc59bf129fc7f6 duration=2.47425ms
panic: duplicate metrics collector registration attempted

goroutine 59 [running]:
github.com/prometheus/client_golang/prometheus.(*Registry).MustRegister(0x11504e240, {0x14003cbddb0?, 0xa?, 0x14001ea156a?})
	github.com/prometheus/[email protected]/prometheus/registry.go:406 +0x78
github.com/grafana/alloy/internal/runtime/internal/controller.NewLoader({{0x1400046f810, {0x10fd81250, 0x14001e4ce80}, {0x10bf89fcd, 0xb}, 0x2, 0x14003cbdb60, 0x14003cbdb20, {0x10fde02d0, 0x11504e240}, ...}, ...})
	github.com/grafana/alloy/internal/runtime/internal/controller/loader.go:110 +0x5e8
github.com/grafana/alloy/internal/runtime.newController({{{0x14001ea1560, 0x2c}, 0x1400046f810, 0x14001e4ce80, {0x10bf89fcd, 0xb}, {0x10fde02d0, 0x11504e240}, 0x2, 0x14003cbdb20, ...}, ...})
	github.com/grafana/alloy/internal/runtime/alloy.go:196 +0x56c
github.com/grafana/alloy/internal/runtime.newModule(0x1400207a930)
	github.com/grafana/alloy/internal/runtime/module.go:133 +0x28c
github.com/grafana/alloy/internal/runtime.(*moduleController).NewCustomComponent(0x14002a28a80, {0x0, 0x0}, 0x14003cbdb10)
	github.com/grafana/alloy/internal/runtime/module.go:76 +0x164
github.com/grafana/alloy/internal/runtime/internal/controller.(*CustomComponentNode).evaluate(0x1400361c340, 0x14003cbdb00)
	github.com/grafana/alloy/internal/runtime/internal/controller/node_custom_component.go:192 +0x198
github.com/grafana/alloy/internal/runtime/internal/controller.(*CustomComponentNode).Evaluate(0x1400361c340, 0x107ef37c4?)
	github.com/grafana/alloy/internal/runtime/internal/controller/node_custom_component.go:167 +0x20
github.com/grafana/alloy/internal/runtime/internal/controller.(*Loader).evaluate(0x1400341e340, {0x10fd58fa0, 0x140042fbcc0}, {0x10fe097a0, 0x1400361c340})
	github.com/grafana/alloy/internal/runtime/internal/controller/loader.go:837 +0x50
github.com/grafana/alloy/internal/runtime/internal/controller.(*Loader).Apply.func2({0x10fd5b480, 0x1400361c340})
	github.com/grafana/alloy/internal/runtime/internal/controller/loader.go:207 +0xd34
github.com/grafana/alloy/internal/runtime/internal/dag.WalkTopological(0x140034aa500, {0x140001c8680, 0x6, 0x114b16c30?}, 0x14006357980)
	github.com/grafana/alloy/internal/runtime/internal/dag/walk.go:83 +0x194
github.com/grafana/alloy/internal/runtime/internal/controller.(*Loader).Apply(0x1400341e340, {0x0, {0x140034aa4e0, 0x3, 0x4}, {0x0, 0x0, 0x0}, {0x140034aa4c0, 0x3, ...}, ...})
	github.com/grafana/alloy/internal/runtime/internal/controller/loader.go:190 +0x894
github.com/grafana/alloy/internal/runtime.(*Runtime).applyLoaderConfig(0x1400345c000, {0x0, {0x140034aa4e0, 0x3, 0x4}, {0x0, 0x0, 0x0}, {0x140034aa4c0, 0x3, ...}, ...})
	github.com/grafana/alloy/internal/runtime/alloy.go:334 +0x108
github.com/grafana/alloy/internal/runtime.(*Runtime).LoadSource(0x1400345c000, 0x1400344ea10, 0x0, {0x16af134bc, 0x24})
	github.com/grafana/alloy/internal/runtime/alloy.go:307 +0x2b4
github.com/grafana/alloy/internal/runtime.ServiceController.LoadSource({0x14003755de8?}, {0x1400634e000?, 0x1?, 0x14010ea4ab0?}, 0x0, {0x16af134bc, 0x24})
	github.com/grafana/alloy/internal/runtime/alloy_services.go:101 +0x80
github.com/grafana/alloy/internal/service/remotecfg.(*Service).parseAndLoad(0x14002631680, {0x1400634e000, 0xfb5, 0x1000})
	github.com/grafana/alloy/internal/service/remotecfg/remotecfg.go:471 +0x11c
github.com/grafana/alloy/internal/service/remotecfg.(*Service).fetchRemote(0x14002631680)
	github.com/grafana/alloy/internal/service/remotecfg/remotecfg.go:392 +0x230
github.com/grafana/alloy/internal/service/remotecfg.(*Service).Run(0x14002631680, {0x10fe08728, 0x14003410370}, {0x10fe18b40?, 0x140027ddc00?})
	github.com/grafana/alloy/internal/service/remotecfg/remotecfg.go:270 +0x134
github.com/grafana/alloy/internal/runtime/internal/controller.(*ServiceNode).Run(0x0?, {0x10fe08728?, 0x14003410370?})
	github.com/grafana/alloy/internal/runtime/internal/controller/node_service.go:124 +0x3c
github.com/grafana/alloy/internal/runtime/internal/controller.newTask.func1()
	github.com/grafana/alloy/internal/runtime/internal/controller/scheduler.go:150 +0x3c
created by github.com/grafana/alloy/internal/runtime/internal/controller.newTask in goroutine 225
	github.com/grafana/alloy/internal/runtime/internal/controller/scheduler.go:149 +0x12c