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syslog-ng Premium Edition 7.0.20 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng The syslog-ng PE quick-start guide The syslog-ng PE configuration file Collecting log messages — sources and source drivers
How sources work default-network-drivers: Receive and parse common syslog messages internal: Collecting internal messages file: Collecting messages from text files wildcard-file: Collecting messages from multiple text files linux-audit: Collecting messages from Linux audit logs network: Collecting messages using the RFC3164 protocol (network() driver) office365: Fetching logs from Office 365 osquery: Collect and parse osquery result logs pipe: Collecting messages from named pipes program: Receiving messages from external applications python: writing server-style Python sources python-fetcher: writing fetcher-style Python sources snmptrap: Read Net-SNMP traps syslog: Collecting messages using the IETF syslog protocol (syslog() driver) system: Collecting the system-specific log messages of a platform systemd-journal: Collecting messages from the systemd-journal system log storage systemd-syslog: Collecting systemd messages using a socket tcp, tcp6, udp, udp6: Collecting messages from remote hosts using the BSD syslog protocol udp-balancer: Receiving UDP messages at very high rate unix-stream, unix-dgram: Collecting messages from UNIX domain sockets windowsevent: Collecting Windows event logs
Sending and storing log messages — destinations and destination drivers
elasticsearch2: Sending messages directly to Elasticsearch version 2.0 or higher (DEPRECATED) elasticsearch-http: Sending messages to Elasticsearch HTTP Event Collector file: Storing messages in plain-text files hdfs: Storing messages on the Hadoop Distributed File System (HDFS) http: Posting messages over HTTP kafka: Publishing messages to Apache Kafka logstore: Storing messages in encrypted files mongodb: Storing messages in a MongoDB database network: Sending messages to a remote log server using the RFC3164 protocol (network() driver) pipe: Sending messages to named pipes program: Sending messages to external applications python: writing custom Python destinations sentinel: Sending logs to the Microsoft Azure Sentinel cloud snmp: Sending SNMP traps smtp: Generating SMTP messages (email) from logs splunk-hec: Sending messages to Splunk HTTP Event Collector sql: Storing messages in an SQL database stackdriver: Sending logs to the Google Stackdriver cloud syslog: Sending messages to a remote logserver using the IETF-syslog protocol syslog-ng(): Forward logs to another syslog-ng node tcp, tcp6, udp, udp6: Sending messages to a remote log server using the legacy BSD-syslog protocol (tcp(), udp() drivers) unix-stream, unix-dgram: Sending messages to UNIX domain sockets usertty: Sending messages to a user terminal — usertty() destination Client-side failover
Routing messages: log paths, flags, and filters Global options of syslog-ng PE TLS-encrypted message transfer Advanced Log Transfer Protocol Reliability and minimizing the loss of log messages Manipulating messages parser: Parse and segment structured messages Processing message content with a pattern database Correlating log messages Enriching log messages with external data Monitoring statistics and metrics of syslog-ng Multithreading and scaling in syslog-ng PE Troubleshooting syslog-ng Best practices and examples The syslog-ng manual pages Glossary

wildcard-file: Collecting messages from multiple text files

The wildcard-file() source collects log messages from multiple plain-text files from multiple directories. The wildcard-file() source is available in syslog-ng PE version 7.0.3 and later.

The syslog-ng PE application notices if a file is renamed or replaced with a new file, so it can correctly follow the file even if logrotation is used. When syslog-ng PE is restarted, it records the position of the last sent log message in the /opt/syslog-ng/var/syslog-ng.persist file, and continues to send messages from this position after the restart.

Declaration
wildcard-file(
    base-dir("<pathname>")
    filename-pattern("<filename>")
);

Note the following important points:

  • You can use the * and ? wildcard characters in the filename (the filename-pattern() option), but not in the path (the base-dir() option).

  • When using the wildcard-file() source, always set how often syslog-ng PE should check the files for new messages using the follow-freq() parameter.

  • If you use multiple wildcard-file() sources in your configuration, make sure that the files and folders that match the wildcards do not overlap. That is, every file and folder should belong to only one file source. Monitoring a file from multiple wildcard sources can lead to data loss.

  • When using wildcards, syslog-ng PE monitors every matching file (up to the limit set in the max-files() option), and can receive new log messages from any of the files. However, monitoring (polling) many files (that is, more than ten) has a significant overhead and may affect performance. On Linux this overhead is not so significant, because syslog-ng PE uses the inotify feature of the kernel. Set the max-files() option at least to the number of files you want to monitor. If the wildcard-file source matches more files than the value of the max-files() option, it is random which files will syslog-ng PE actually monitor. The default value of max-files() is 100.

  • If the message does not have a proper syslog header, syslog-ng PE treats messages received from files as sent by the kern facility. Use the default-facility() and default-priority() options in the source definition to assign a different facility if needed.

Required parameters: base-dir(), filename-pattern(). For the list of available optional parameters, see wildcard-file() source options.

Example: Using the wildcard-file() driver

The following example monitors every file with the .log extension in the /var/log directory for log messages.

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