Expvar Receiver

Available in: contrib Maintainers: @jamesmoessis, @MovieStoreGuy Source: opentelemetry-collector-contrib

Supported Telemetry

Overview

Configuration

Default

By default, without any configuration, a request will be sent to http://localhost:8000/debug/vars every 60 seconds. The default configuration is achieved by the following:

receivers:
  expvar:

Customising

The following can be configured:

Configure the HTTP client for scraping the expvar variables. The full set of configuration options for the client can be found in the core repo’s confighttp.
- defaults:
  - endpoint = http://localhost:8000/debug/vars
  - timeout = 3s
collection_interval - Configure how often the metrics are scraped.
- default: 1m
initial_delay (default = 1s): defines how long this receiver waits before starting.
metrics - Enable or disable metrics by name.

Example configuration

receivers:
  expvar:
    endpoint: "http://localhost:8000/custom/path"
    timeout: 1s
    collection_interval: 30s
    metrics:
      process.runtime.memstats.total_alloc:
        enabled: true
      process.runtime.memstats.mallocs:
        enabled: false

Metrics

Metric Name	Description	Unit	Type	Attributes
✅ `process.runtime.memstats.buck_hash_sys`	Bytes of memory in profiling bucket hash tables.	By	UpDownCounter
✅ `process.runtime.memstats.frees`	Cumulative count of heap objects freed.	{objects}	Counter
✅ `process.runtime.memstats.gc_cpu_fraction`	The fraction of this program’s available CPU time used by the GC since the program started.	1	Gauge
✅ `process.runtime.memstats.gc_sys`	Bytes of memory in garbage collection metadata.	By	UpDownCounter
✅ `process.runtime.memstats.heap_alloc`	Bytes of allocated heap objects.	By	UpDownCounter
✅ `process.runtime.memstats.heap_idle`	Bytes in idle (unused) spans.	By	UpDownCounter
✅ `process.runtime.memstats.heap_inuse`	Bytes in in-use spans.	By	UpDownCounter
✅ `process.runtime.memstats.heap_objects`	Number of allocated heap objects.	{objects}	UpDownCounter
✅ `process.runtime.memstats.heap_released`	Bytes of physical memory returned to the OS.	By	UpDownCounter
✅ `process.runtime.memstats.heap_sys`	Bytes of heap memory obtained by the OS.	By	UpDownCounter
✅ `process.runtime.memstats.last_pause`	The most recent stop-the-world pause time.	ns	Gauge
❌ `process.runtime.memstats.lookups`	Number of pointer lookups performed by the runtime.	{lookups}	UpDownCounter
✅ `process.runtime.memstats.mallocs`	Cumulative count of heap objects allocated.	{objects}	Counter
✅ `process.runtime.memstats.mcache_inuse`	Bytes of allocated mcache structures.	By	UpDownCounter
✅ `process.runtime.memstats.mcache_sys`	Bytes of memory obtained from the OS for mcache structures.	By	UpDownCounter
✅ `process.runtime.memstats.mspan_inuse`	Bytes of allocated mspan structures.	By	UpDownCounter
✅ `process.runtime.memstats.mspan_sys`	Bytes of memory obtained from the OS for mspan structures.	By	UpDownCounter
✅ `process.runtime.memstats.next_gc`	The target heap size of the next GC cycle.	By	UpDownCounter
✅ `process.runtime.memstats.num_forced_gc`	Number of GC cycles that were forced by the application calling the GC function.	By	Counter
✅ `process.runtime.memstats.num_gc`	Number of completed GC cycles.	By	Counter
✅ `process.runtime.memstats.other_sys`	Bytes of memory in miscellaneous off-heap runtime allocations.	By	UpDownCounter
✅ `process.runtime.memstats.pause_total`	The cumulative nanoseconds in GC stop-the-world pauses since the program started.	By	Counter
✅ `process.runtime.memstats.stack_inuse`	Bytes in stack spans.	By	UpDownCounter
✅ `process.runtime.memstats.stack_sys`	Bytes of stack memory obtained from the OS.	By	UpDownCounter
✅ `process.runtime.memstats.sys`	Total bytes of memory obtained from the OS.	By	UpDownCounter
❌ `process.runtime.memstats.total_alloc`	Cumulative bytes allocated for heap objects.	By	Counter

Configuration

Example Configuration

# The default, minimal configuration
expvar/default:

# More custom configuration
expvar/custom:
  endpoint: "http://localhost:8000/custom/path"
  timeout: 5s
  collection_interval: 30s
  metrics:
    process.runtime.memstats.total_alloc:
      enabled: true
    process.runtime.memstats.mallocs:
      enabled: false

expvar/bad_hostless_endpoint:
  endpoint: "https:///this/aint/a/good/endpoint"

expvar/bad_invalid_url:
  endpoint: "#$%^&*()_"

expvar/bad_schemeless_endpoint:
  endpoint: "localhost:8000/custom/path"

Last generated: 2026-10-05