logagent-js

logagent-js

Smart Log Parser and Log Shipper written in Node.

The parser detects log formats based on a pattern library (yaml file) and converts it to a JSON Object:

• find matching regex in pattern library
• tag it with the recognized type
• extract fields using regex
• parse dates and detect date format (use 'ts' field for date and time combined)
• create ISO timestamp in '@timestamp' field
• transform function to manipulate parsed objects
• unmatched lines end up with timestamp and original line in the message field

To test patterns or convert logs from text to JSON use the command line tool 'logagent'. It reads from stdin and outputs line delemited JSON (or pretty JSON or YAML) to the console. In addtion it can forward the parsed objects directly to Logsene.

Pattern definitions file

The file format is based on JS-YAML, in short:

• • indicates an array
• !js/regexp - indicates a JS regular expression
• !!js/function > - indicates a JS function

Properties:

• patterns - the list of patterns, each pattern starts with "-"
• match: A group of patterns for a specific log source
• regex: a JS regular expression
• fields: the field list of extracted match groups from the regex
• type: the type used in Logsene (Elasticsearch Mapping)
• dateFormat: the format of the special fields 'ts', if the date format matches, a new field @timestamp is generated
• transform: a JS function to manipulate the result of regex and date parsing

Example:

patterns: 
  - # APACHE  Web Logs
  sourceName: httpd
  match: 
    # Common Log Format
    - regex:        !!js/regexp /([0-9a-f.:]+)\s+(-|.+?)\s+(-|.+?)\s+\[([0-9]{2}\/[a-z]{3}\/[0-9]{4}\:[0-9]{2}:[0-9]{2}:[0-9]{2}[^\]]*)\] \"(\S+?)\s(\S*?)\s{0,1}(\S+?)\" ([0-9|\-]+) ([0-9|\-]+)/i
      type: apache_access_common
      fields:       [client_ip,remote_id,user,ts,method,path,http_version,status_code,size]
      dateFormat: DD/MMM/YYYY:HH:mm:ss ZZ
      transform: !!js/function >
        function (p) {
          p.message = p.method + ' ' + p.path
        }

The default patterns are here - contributions are welcome.

Use logagent-js in Node

Install it as local package

npm i sematext/logagent-js

Use the Logparser module in your source code

var Logparser = require('logagent-js')
var lp = new Logparser('./patterns.yml')
lp.parseLine('log message', 'source name', function (err, data) {
    if(err) {
      console.log('line did not match with any pattern')
    }
    console.log(JSON.stringify(data))
})

Test your patterns:

cat some.log | bin/logagent -y -f mypatterns.yml

Installation for the command line tool

Get Node.js (debian/ubuntu)

# Note the new setup script name for Node.js v0.12
curl -sL https://deb.nodesource.com/setup_0.12 | sudo bash -
# Then install with:
sudo apt-get install -y nodejs

Install logagent-js globally

npm i -g sematext/logagent-js
# ship all your logs to logsene, parsed, timestamped - displyed on console in YAML format (-y)
logagent -t LOGSENE_TOKEN -y /var/log/*.log

Parameters:

• -f file with pattern definitions
• -y prints parsed messages in YAML format
• -p pretty json output
• -s silent, print only throughput
• -t token Logsene App Token to insert parsed records into Logsene
• -g use a glob pattern to watch log files e.g. -g "{/var/log/.log,/Users/stefan//*.log}"
• list of files, watched by tail-forver starting at end of file to watch

The default output is line delimited JSON.

Examples:

# Be Evil: parse all logs 
# stream it to Logsene 1-Click ELK stack 
logagent -t LOGSENE_TOKEN /var/log/*.log 

Use a glob pattern to build the file list

logagent -t LOGSENE_TOKEN -g "{/var/log/*.log,/opt/myapp/*.log}" 

Watch selective log output on console by passing logs via stdin and format in YAML

tail -f /var/log/access.log | logagent -y 
tail -f /var/log/system.log | logagent -f my_own_patterns.yml  -y 

Run logagent as system service to monitor all logs e.g. in /var/log/

Upstart script (ubuntu)

Modify this script and place it in /etc/init/logagent.conf

description "Upstart Logagent"

start on (local-filesystems and net-device-up IFACE=eth0)
stop on runlevel [!12345]

respawn

setuid syslog
setgid syslog
env NODE_ENV=production
env LOGSENE_TOKEN=YOUR_LOGSENE_TOKEN
chdir  /var/log

exec /usr/local/bin/logagent -s /var/log/*.log 

Start the service:

sudo service logagent start

Unit file for systemd startup

Create a service file for the logagent, in /etc/systemd/system/logagent.service Set the Logsene Token and file list in "ExecStart" directive.

[Service]
Description=Sematext logagent-js
Environment=NODE_ENV=production
ExecStart=/usr/local/bin/logagent -s -t YOUR_LOGSENE_TOKEN /var/log/*.log
Restart=always
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=logagent
User=syslog
Group=syslog

[Install]
WantedBy=multi-user.target

Start the service

systemctl start logagent

Related packages

• Logsene-CLI - Enables searching Logsene log entries from the command-line.
• SPM Agent for Docker - collects metrics, events and logs from Docker API and CoreOS
• SPM Agent for Node.js - collects performance metrics for Node and io.js applications
• Custom Metrics - Custom Metrics for SPM
• Winston-Logsene - Logging for Node.js - Winston transport layer for Logsene

Support

• Twitter: @sematext
• Blog: blog.sematext.com
• Homepage: www.sematext.com