# nodejsCaptureMode

This is an optional argument that selects how the yc-360 script captures diagnostics from a Node.js application: through the yCrash hook loaded into the process, or through Node's own built in signal based flags.

Type: string

Default: hook

Supported values

Value Description
hook Captures through the yCrash Node.js hook. Full artifact set. Default.
signal Captures through Node's built in --report-on-signal and --trace-gc flags, with no hook required. Reduced artifact set. Linux and macOS only.

Usage:

  • Omitted: the script assumes Hook Mode and expects the target application to have the yCrash Node.js hook loaded.
  • Specified as signal: the script falls back to Signal Mode. Your application must be started with --report-on-signal and, for GC data, --trace-gc.

How it works:

  1. When omitted, the yc-360 script looks for a running hook instance registered by the target Node.js process and captures the full diagnostic set through it.
  2. When set to signal, the script instead sends the configured signal to the target process and reads the resulting diagnostic report, without requiring the hook to be loaded.
  3. This argument only takes effect when appRuntime is set to nodejs.

See Node.js Diagnostic Capture for a full comparison of what each mode captures.

Example (YAML):

options:
  onlyCapture: true
  appRuntime: nodejs
  nodejsCaptureMode: signal
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Example (CLI):

./yc -onlyCapture -p 22534 -appRuntime=nodejs -nodejsCaptureMode=signal
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