Pino GELF HTTP

Pino GELF (pino-gelf-http) is a transport for the Pino logger. Pino GELF receives Pino logs from stdin and transforms them into GELF format before sending them to a remote Graylog server via HTTP.

Contents

• Installation
• Usage
• Example I/O
• GELF
• Log Level Mapping
• Acknowledgements

Installation

Pino GELF should be installed globally so it can be used as a utility:

npm i -g pino-gelf-http

Usage

The recommended pipeline to run Pino GELF as a transform for Pino logs is as follows:

node your-app.js | pino-gelf-http log

The host, port and maximum chunk size of your Graylog server can be specified using options. Fields logged by express-pino-middleware or any other custom fields included with Pino requests will be converted into strings (if they aren't already) and their keys will be prefixed with an underscore, according to the GELF spec. Also, you can choose to enable verbose mode which outputs all GELF messages locally, this can be useful for initial configuration.

Finally, you can enable passthrough mode which will output the original input back to stdout. That enables you to make pino-gelf-http part of a chain of commands and use the original input for further processing (for example pino-pretty).

// Set Graylog URL
node your-app.js | pino-gelf-http log -h https://graylog.server.com/gelf

// Enable local output
node your-app.js | pino-gelf-http log -v

// Enable passthrough mode
node your-app.js | pino-gelf-http log -t

Note: The defaults for these options are:

Property	Default
Host	127.0.0.1
Port	12201
Maximum Chunk Size	1420
Verbose Logging	false
Passthrough	false

Example

Given the Pino log message (formatted as JSON for readability):

{
  "pid":16699,
  "hostname":"han",
  "name":"pino-gelf-http-test-app",
  "level":30,
  "time":1481840140708,
  "msg":"request completed",
  "res":{
    "statusCode":304,
    "header":"HTTP/1.1 304 Not Modified\r\nX-Powered-By: Express\r\nETag: W/\"d-bNNVbesNpUvKBgtMOUeYOQ\"\r\nDate: Thu, 15 Dec 2016 22:15:40 GMT\r\nConnection: keep-alive\r\n\r\n"
  },
  "responseTime":8,
  "environment":"dev",
  "colour":"black",
  "req":{
    "id":1,
    "method":"GET",
    "url":"/",
    "headers":{
      "host":"localhost:3000",
      "connection":"keep-alive",
      "if-none-match":"W/\"d-bNNVbesNpUvKBgtMOUeYOQ\"",
      "upgrade-insecure-requests":"1",
      "accept":"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
      "user-agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/602.2.14 (KHTML, like Gecko) Version/10.0.1 Safari/602.2.14",
      "accept-language":"en-gb",
      "dnt":"1",
      "accept-encoding":"gzip, deflate"
    },
    "remoteAddress":"::1",
    "remotePort":52829
  },
  "v":1
}

And the usage:

node server.js | pino-gelf-http log

Pino GELF will send the following message to your Graylog server (formatted here as JSON for readability):

Formatted JSON Data
{  
  "version":"1.1",
  "host":"han",
  "short_message":"request completed",
  "full_message":"request completed",
  "timestamp":1481840140.708,
  "level":6,
  "_name":"pino-gelf-http-test-app",
  "_res":"{\"statusCode\":304,\"header\":\"HTTP/1.1 304 Not Modified\\r\\nX-Powered-By: Express\\r\\nETag: W/\\\"d-bNNVbesNpUvKBgtMOUeYOQ\\\"\\r\\nDate: Thu, 15 Dec 2016 22:15:40 GMT\\r\\nConnection: keep-alive\\r\\n\\r\\n\"}",
  "_responseTime":"8",
  "_environment":"dev",
  "_colour":"black",
  "_req":"{\"id\":1,\"method\":\"GET\",\"url\":\"/\",\"headers\":{\"host\":\"localhost:3000\",\"connection\":\"keep-alive\",\"if-none-match\":\"W/\\\"d-bNNVbesNpUvKBgtMOUeYOQ\\\"\",\"upgrade-insecure-requests\":\"1\",\"accept\":\"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\",\"user-agent\":\"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/602.2.14 (KHTML, like Gecko) Version/10.0.1 Safari/602.2.14\",\"accept-language\":\"en-gb\",\"dnt\":\"1\",\"accept-encoding\":\"gzip, deflate\"},\"remoteAddress\":\"::1\",\"remotePort\":52829}"
}

GELF

At present the mapping from standard Pino log messages to GELF messages is as follows:

GELF Property	Pino Log Property	Notes
version	-	Hardcoded to 1.1 per GELF docs
host	hostname	-
short_message	msg	msg is truncated to 64 characters
full_message	msg	msg is not truncated
timestamp	time	-
level	level	Pino level is mapped to SysLog levels1

Log Level Mapping

The mapping from Pino log levels to SysLog levels used by GELF are as follows:

Pino Log Level	SysLog Level
Trace	Debug
Debug	Debug
Info	Info
Warn	Warning
Error	Error
Fatal	Critical

Note: Pino log messages without a level map to SysLog Critical

Acknowledgements

The implementation of Pino GELF is based in large part on pino-gelf.