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https://github.com/yahoo/monitr
A Node.js process monitoring tool.
https://github.com/yahoo/monitr
cpp nodejs process-monitoring web
Last synced: about 2 months ago
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A Node.js process monitoring tool.
- Host: GitHub
- URL: https://github.com/yahoo/monitr
- Owner: yahoo
- License: bsd-3-clause
- Created: 2013-09-23T17:54:25.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2023-10-19T08:23:02.000Z (11 months ago)
- Last Synced: 2024-07-11T21:33:36.972Z (2 months ago)
- Topics: cpp, nodejs, process-monitoring, web
- Language: C++
- Homepage:
- Size: 177 KB
- Stars: 318
- Watchers: 29
- Forks: 39
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-repositories - yahoo/monitr - A Node.js process monitoring tool. (C++)
README
# monitr
Nodejs process monitoring module
This package is tested only with Node.js LTS versions.
_Note: This module currently works only on Linux operating systems_.
## External statistics reporting
This module starts a separate thread within the Nodejs runtime that
monitors and collects statistics about the running nodejs process.
These statistics are then sent as JSON messages via UDP datagrams over
a local domain socket.
Here is the list of data the module reports periodically:
```
{ status:
{ pid: ,
ts: ,
cluster: ,
reqstotal: ,
utcstart: ,
events: ,,
cpu: ,
mem: ,
cpuperreq: ,
oreqs: ,
sys_cpu: ,
oconns: ,
user_cpu: ,
rps: ,
kbs_out: ,
elapsed:
## GC introspection
It provides the running nodejs application with the ability to
introspect garbage collection activity by creating read-only
properties at `process.monitor.gc` that reports:
1. `count`: number of times GC stop-the-world events occurred
2. `elapsed`: cumulative time (in milliseconds) spent in GC
# Installation
With [npm](http://npmjs.org) do:
```
npm install monitr
```
# Usage
```js
var monitor = require('monitr');
```
## start()
```js
monitor.start();
```
Spawns a thread and monitors the process. Writes process stats every second to the socket path.
## stop()
```js
monitor.stop();
```
Terminates the thread and closes the socket.
## setIpcMonitorPath(socketPath)
```js
monitor.setIpcMonitorPath('/tmp/my-process-stats.mon');
```
Sets the datagram socket name to write the stats. Defaults to /tmp/nodejs.mon
# Health Status
Monitr supports custom health functionality whereby the app can report its own health.
The following methods are added to process.monitor to set and get the health information.
```js
setHealthStatus(isDown, statusCode)
isDown()
getStatusCode()
getStatusTimestamp() - Return seconds when setHealthStatus was last called
getStatusDate() - Return Date object
```
Once setHealthStatus is invoked, the status json, described above, will have following additional fields.
```js
health_status_timestamp: ,
health_is_down: ,
health_status_code:
```
# Handling HUP events
`Monitr` installs a custom `SIGHUP` handler which will optionally
print out a NodeJS stack backtrace of the Javascript currently being
executed. This can be useful for debugging where a NodeJS process may
be _stuck_.
# Implementation
It looks up /proc/* files on the system to report CPU Usage. It looks
up /proc/pid/* files on the system to report its own stats.
`process.monitor.*` methods are set by `lib/monitor.js`.
It calls the process.monitor.* methods to report total requests since
monitoring started (`reqstotal`), current requests in flight
(`oreqs`), current open connections (`oconns`) and total data returned
since monitoring started (`kb_trans`). _Note: `oreqs` may be greater
than `oconns` when keepalive is enabled_.
It attaches to the v8 garbage collection hooks to instrument (for each
GC type) the following stats for each reporting interval.
1. `count` : number of times GC type invoked
2. `elapsed_ms`: total elapsed time nodejs thread is blocked
3. `max_ms`: maximum time spent blocked by any one GC event
# Example
Please refer to examples/README.md for examples showing the use of these functions.
# Build Status
[](http://travis-ci.org/yahoo/monitr)
# Node Badge
[](https://nodei.co/npm/monitr/)