# Nginx Access Logs

You can tail Nginx access logs from Treasure Agent (td-agent), to continuously import the access logs into the cloud.

Continue to the following topics:

## Installing td-agent

‘td-agent’ must 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.

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

| OS | Link |
|  --- | --- |
| MacOS X | [Installing td-agent on MacOS X](https://docs.fluentd.org/installation/install-by-dmg) |
| Ubuntu System | [Installing td-agent for Debian and Ubuntu](https://docs.fluentd.org/installation/install-by-deb) |
| RHEL / CentOS System | [Installing td-agent for Redhat and CentOS](http://docs.fluentd.org/installation/install-by-rpm) |
| AWS Elastic Beanstalk | [Installing td-agent on AWS Elastic Beanstalk](https://github.com/treasure-data/elastic-beanstalk-td-agent) |


## Modifying td-agent.conf

Specify your authentication key by setting the `apikey` option. You can view your API key from the [TD Console](https://console.treasuredata.com/app/users/current).

Access /etc/td-agent/td-agent.conf to set the `apikey` option in your td-agent.conf file.

Note: *YOUR_API_KEY* should be your API key string.


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

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

Restart your agent when the following lines are in place.


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

td-agent keeps tailing the log, buffers the log (*var/log/td-agent/buffer/td*), and automatically uploads the log into the cloud.

## Confirm Data Import

Sending a SIGUSR1 signal flushes td-agent’s buffer; upload starts immediately.


```bash
# 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 follows.


```bash
$ td tables
+------------+------------+------+-----------+
| Database   | Table      | Type | Count     |
+------------+------------+------+-----------+
| production | access     | log  | 1         |
+------------+------------+------+-----------+
```

Check `/var/log/td-agent.log` if it’s not working correctly. `td-agent:td-agent` must have 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, because 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.

- [Schema Management](https://docs.treasuredata.com/articles/project-product-documentation/schema+Management)
- [Hive Query Language](https://docs.treasuredata.com/articles/project-product-documentation/hive-reference)
- [Programmatic Access with REST API and its Bindings](https://docs.treasuredata.com/articles/project-product-documentation/rest-apis-in-treasure-data)