Introduction
Updated at:2025-11-03
Using the example of logs continuously generated by a server, this document introduces the basic concepts and log collection process of Baidu Log Service (BLS).
Basic concepts
- Agent: An agent is a service component provided by the log service, installed within an instance. It ensures safe and reliable log collection, guarantees the normal operation of applications, and includes a comprehensive exception handling mechanism.
- Token: A token is a verification string used to authenticate the user's identity. It is included in the agent's configuration file and must be securely stored.
- Transmission task: A transmission task is a unit for executing and managing log services, allowing the configuration and management of log sources, delivery addresses, collection rules, and more.
Operation process

Log format
The log service supports text-format logs encoded in UTF-8.
Sample log information used in this document
- The server's log files are stored in the /home/work/nginx_logs directory.
- Each day's logs are saved in a separate file. The file being actively written to is named ".log", and a timestamp in the format ".yyyy-mm-dd" is appended to completed log files.
Log information is as follows:
Plain Text
1 #ls -al /home/work/nginx_logs
2 drwxr-xr-x.2 work work 4096 June 16 08:35 .
3 drwxr-xr-x.3 work work 4096 June 5 08:35 .
4 -rw-r--r--.1 work work 3396 June 16 08:35 access.log
5 -rw-r--r--.1 work work 4843 June 12 12:34 access.log.2016-06-12
6 -rw-r--r--.1 work work 9686 June 13 14:21 access.log.2016-06-13
7 -rw-r--r--.1 work work 7322 June 14 10:35 access.log.2016-06-14
8 -rw-r--r--.1 work work 7062 June 15 10:55 access.log.2016-06-15
The file "access.log" refers to logs being written on June 16, 2016, while "access.log.2016-06-15" is a completed log file from June 15.
Subsequent sections will cover the installation of agents and the creation of transmission tasks.
