Tailing Nginx Access Logs

This article explains how to tail Nginx access logs from td-agent, to continuously import the access logs into the cloud.

Table of Contents

Installing td-agent

‘td-agent’ needs to be installed on your application servers. td-agent is a daemon program dedicated to the streaming upload of any kind of the time-series data. td-agent is developed and maintained by Treasure Data, Inc.

To set up td-agent, please refer to the following articles; we provide deb/rpm packages for Linux systems.

If you have... Please refer to...
MacOS X Installing td-agent on MacOS X
Ubuntu System Installing td-agent for Debian and Ubuntu
RHEL / CentOS System Installing td-agent for Redhat and CentOS
AWS Elastic Beanstalk Installing td-agent on AWS Elastic Beanstalk
td-agent is fully open-sourced under the fluentd project. td-agent extends fluentd with custom plugins for Treasure Data.

Modifying /etc/td-agent/td-agent.conf

Next, please specify your authentication key by setting the apikey option. You can view your api key from the console. Next, please set the apikey option in your td-agent.conf file.

Note: YOUR_API_KEY should be your actual apikey string.

# Tailing the Apache Log
  type tail
  path /var/log/nginx/access.log
  pos_file /var/log/td-agent/nginx-access.pos
  tag td.production.access
  format nginx

# Treasure Data Input and Output
<match td.*.*>
  type tdlog
  endpoint api.treasuredata.com
  apikey YOUR_API_KEY
  buffer_type file
  buffer_path /var/log/td-agent/buffer/td
  use_ssl true

Please restart your agent once these lines are in place.

$ sudo /etc/init.d/td-agent restart

td-agent will now keep tailing the log, buffer it (var/log/td-agent/buffer/td), and automatically upload it into the cloud.

Confirming Data Import

Sending a SIGUSR1 signal will flush td-agent’s buffer; upload will start immediately.

# generate access logs
$ curl http://host:port/

# flush the buffer
$ kill -USR1 `cat /var/run/td-agent/td-agent.pid`

To confirm that your data has been uploaded successfully, issue the td tables command as shown below.

$ td tables
| Database   | Table      | Type | Count     |
| production | access     | log  | 1         |

Please check /var/log/td-agent.log if it’s not working correctly. td-agent:td-agent needs to have a permission to access the logs.

td-agent handles log-rotation. td-agent keeps a record of the last position of the log, ensuring that each line is read exactly once even if the td-agent process goes down. However, since the information is kept in a file, the "exactly once" guarantee breaks down if the file becomes corrupted.

Next Steps

We offer a schema mechanism that is more flexible than that of traditional RDBMSs. For queries, we leverage the Hive Query Language.

Last modified: May 19 2016 02:28:09 UTC

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