Node.js runtime metrics

The SkyWalking Node.js agent reports runtime metrics (process memory and CPU) through the MeterReportService gRPC protocol—the same pipeline used by the Go and Python agents. OAP analyzes raw meters via meter-analyzer-config/nodejs-runtime.yaml and stores meter_instance_nodejs_* metrics at the service instance level.

Platform support

Runtime meters are collected on Linux, macOS, and Windows via Node.js built-in APIs (process.memoryUsage(), process.cpuUsage(), process.uptime(), v8.getHeapStatistics(), v8.getHeapSpaceStatistics()).

Data flow

On each report interval (default 20 seconds), the agent samples Node.js runtime APIs and maps them into MeterData protobuf messages.
The latest gauge snapshot is sent to OAP over gRPC port 11800 via MeterReportService.collect (independent from trace export on the same address).
OAP applies MAL rules in nodejs-runtime.yaml and exposes meter_instance_nodejs_* metrics.
Horizon UI renders widgets on General Service → Instance → Dashboard when the corresponding meter_instance_nodejs_* metrics exist.

Agent setup

Runtime metric reporting is on by default. Relevant environment variables:

Variable	Description	Default
`SW_AGENT_NODEJS_RUNTIME_METRICS_REPORTER_ACTIVE`	Master switch for runtime metric export	`true`
`SW_AGENT_NODEJS_RUNTIME_METRICS_REPORT_PERIOD`	Sample + report interval in milliseconds	`20000`

Deprecated aliases SW_AGENT_RUNTIME_METRICS_* / SW_AGENT_NVM_* for reporter active and report period are still accepted.

See the Node.js agent README for startup examples and the full field mapping from Node.js APIs to meter names.

OAP setup

Ensure the gRPC receiver is reachable on the port configured in SW_AGENT_COLLECTOR_BACKEND_SERVICES (default 11800). The nodejs-runtime meter analyzer file is included in the default meterAnalyzerActiveFiles list—no extra configuration is required for current Node.js agents.

Meter rules live in oap-server/server-starter/src/main/resources/meter-analyzer-config/nodejs-runtime.yaml.

UI location

Layer: General Service (GENERAL)

Path: select a Node.js service → Instance → Dashboard

Widgets appear only when runtime data is present (visibleWhen checks each meter_instance_nodejs_* expression).

Runtime metrics

The agent reports twelve raw meter names; OAP prefixes them with meter_ when exposing queryable metrics:

Unit	Agent meter name	OAP / UI metric name	Description	Data Source
%	`instance_nodejs_process_cpu`	`meter_instance_nodejs_process_cpu`	Process CPU (user + system) over the report interval	SkyWalking Node.js Agent
bytes	`instance_nodejs_heap_used`	`meter_instance_nodejs_heap_used`	V8 heap used	SkyWalking Node.js Agent
bytes	`instance_nodejs_heap_total`	`meter_instance_nodejs_heap_total`	V8 heap total	SkyWalking Node.js Agent
bytes	`instance_nodejs_heap_limit`	`meter_instance_nodejs_heap_limit`	V8 max heap size	SkyWalking Node.js Agent
bytes	`instance_nodejs_rss`	`meter_instance_nodejs_rss`	Resident set size	SkyWalking Node.js Agent
bytes	`instance_nodejs_external_memory`	`meter_instance_nodejs_external_memory`	External memory	SkyWalking Node.js Agent
bytes	`instance_nodejs_array_buffers`	`meter_instance_nodejs_array_buffers`	ArrayBuffer / SharedArrayBuffer memory	SkyWalking Node.js Agent
s	`instance_nodejs_uptime`	`meter_instance_nodejs_uptime`	Process uptime	SkyWalking Node.js Agent
bytes	`instance_nodejs_peak_malloced_memory`	`meter_instance_nodejs_peak_malloced_memory`	Peak V8 malloced memory	SkyWalking Node.js Agent
bytes	`instance_nodejs_malloced_memory`	`meter_instance_nodejs_malloced_memory`	Current V8 malloced memory	SkyWalking Node.js Agent
bytes	`instance_nodejs_old_space_used`	`meter_instance_nodejs_old_space_used`	V8 old generation heap used	SkyWalking Node.js Agent
bytes	`instance_nodejs_new_space_used`	`meter_instance_nodejs_new_space_used`	V8 new generation heap used	SkyWalking Node.js Agent

Customizations

You can customize MAL expressions or dashboard panels. Metric definitions and expression rules are in meter-analyzer-config/nodejs-runtime.yaml. Instance dashboard widget templates ship from the SkyWalking Horizon UI bundle (general.json in apache/skywalking-horizon-ui).