Logging

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This article is part of the Advanced User's Guide. It describes how client operations are logged by the server. The server logs can e.g. be used to get an overview of all processes executed on your server, trace any errors or compile performance statistics.

Introduction

The server logs are written in plain text. In your Database Directory, you can find a folder named .logs in which all log files are stored with the according date. Note that, depending on your OS and configuration, files and folders beinning with a . may be hidden. The log directory can be changed via the LOGPATH option.

If BaseX is used in a Web Application, all trace output (generated via fn:trace, prof:dump and similar functions) will be stored in the logs as well.

Some more notes on the logging facility:

  • HTTP requests are included in the log files.
  • Logging can be turned on/off via the LOG option.
  • The maximum length of logging messages can be changed via LOGMSGMAXLEN.
  • The Admin Module provides access to the log files from XQuery.

RESTXQ

By default, RESTXQ code is executed with the admin user. As a result, this user will be displayed in the logs for all RESTXQ requests. In a web application with a custom user management, however, the name of the actual user who has sent a request is often more relevant.

When log data is written during the processing of a RESTXQ function, the following is looked up as follows:

  1. The current request is checked for an id attribute. The attribute can be assigned via RESTXQ and the request:set-attribute function, and it is the recommended approach for stateless requests as all request attributes will be dropped after the finalization of a request.
  2. If none is found, the id attribute is looked up in the current user session. The attribute can be assigned via session:set (see e. g. the DBA code for sessions and user handling). If the request path contains a dba segment, a dba session attribute will be looked up instead.
  3. If none is found, the default path will be taken, and the user of the current database context will be included in the logs.

Format

Example 1

<syntaxhighlight> 01:18:12.892 SERVER admin OK Server was started (port: 1984) 01:18:15.436 127.0.0.1:4722 jack REQUEST XQUERY for $i in 1 to 5 return random:double() 01:18:15.446 127.0.0.1:4722 jack OK Query executed in 2.38 ms. 2.72 ms 01:18:15.447 127.0.0.1:4722 jack REQUEST EXIT 01:18:15.447 127.0.0.1:4722 jack OK 0.39 ms </syntaxhighlight>

A server has been started and a user jack has connected to the server to perform a query and exit properly.

Example 2

<syntaxhighlight> 01:23:33.251 127.0.0.1:4736 john OK QUERY[0] 'hi' 0.44 ms 01:23:33.337 127.0.0.1:4736 john OK ITER[0] 1.14 ms 01:23:33.338 127.0.0.1:4736 john OK INFO[0] 0.36 ms 01:23:33.339 127.0.0.1:4736 john OK CLOSE[0] 0.21 ms 01:23:33.359 127.0.0.1:4736 john REQUEST EXIT 01:23:33.359 127.0.0.1:4736 john OK 0.14 ms </syntaxhighlight>

A user john has performed an iterative query, using one of the client APIs.

Example 3

<syntaxhighlight> 01:31:51.888 127.0.0.1:4803 admin REQUEST [GET] http://localhost:8984/rest/factbook 01:31:51.892 127.0.0.1:4803 admin 200 4.43 ms </syntaxhighlight>

An admin user has accessed the factbook database via REST.

Changelog

Version 9.3
  • Updated: Store trace output in database logs
  • Updated: RESTXQ: The request attributes will be checked for a user id.
Version 8.6
  • Added: The log directory can be changed with the LOGPATH option.
  • Updated: Include session attributes in log data.