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syslog-ng Premium Edition 7.0.34 - Administration Guide

Preface Introduction to syslog-ng The concepts of syslog-ng Installing syslog-ng PE 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 google-pubsub: collecting messages from the Google Pub/Sub messaging service wildcard-file: Collecting messages from multiple text files linux-audit: Collecting messages from Linux audit logs mssql, oracle, sql: collecting messages from an SQL database 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 google_bigquery(): Sending logs to a Google BigQuery table google_bigquery_managedaccount(): Sending logs to a Google BigQuery table authenticated by Google Cloud managed service account google_pubsub(): Sending logs to the Google Cloud Pub/Sub messaging service google_pubsub-managedaccount(): Sending logs to the Google Cloud Pub/Sub messaging service authenticated by Google Cloud managed service account hdfs: Storing messages on the Hadoop Distributed File System (HDFS) http: Posting messages over HTTP kafka(): Publishing messages to Apache Kafka (Java implementation) (DEPRECATED) kafka-c(): Publishing messages to Apache Kafka using the librdkafka client (C implementation) 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 Transport 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

logstore() destination options

The logstore driver stores log messages in binary files that can be encrypted, compressed, checked for integrity, and timestamped by an external Timestamping Authority (TSA). Otherwise, it is very similar to the file() destination.

Caution:

When creating several thousands separate log files, syslog-ng might not be able to open the required number of files. This might happen for example, when using the ${HOST} macro in the filename while receiving messages from a large number of hosts. To overcome this problem, adjust the --fd-limit command-line parameter of syslog-ng or the global ulimit parameter of your host. For setting the --fd-limit command-line parameter of syslog-ng see the The syslog-ng manual page manual page. For setting the ulimit parameter of the host, see the documentation of your operating system.

NOTE:

When using this destination, update the configuration of your log rotation program to rotate these files. Otherwise, the log files can become very large.

Also, after rotating the log files, reload syslog-ng PE using the syslog-ng-ctl reload command, or use another method to send a SIGHUP to syslog-ng PE.

The logstore() has a single required parameter that specifies the filename that stores the log messages.

Declaration
logstore(filename options());

The logstore() destination has the following options:

cipher()
Type: string
Default: aes-128-cbc

Description: Set the cipher method used to encrypt the logstore. The following cipher methods are available: aes-128-cbc, aes-128-cfb, aes-128-cfb1, aes-128-cfb8, aes-128-ecb, aes-128-ofb , aes-192-cbc, aes-192-cfb, aes-192-cfb1, aes-192-cfb8, aes-192-ecb, aes-192-ofb , aes-256-cbc, aes-256-cfb, aes-256-cfb1, aes-256-cfb8, aes-256-ecb, aes-256-ofb , aes128 , aes192 , aes256, bf , bf-cbc , bf-cfb, bf-ecb , bf-ofb , blowfish, cast , cast-cbc , cast5-cbc , cast5-cfb, cast5-ecb, cast5-ofb , des, des-cbc, des-cfb , des-cfb1 , des-cfb8 , des-ecb , des-ede, des-ede-cbc, des-ede-cfb , des-ede-ofb, des-ede3 , des-ede3-cbc, des-ede3-cfb, des-ede3-ofb, des-ofb , des3 , desx , desx-cbc, rc2, rc2-40-cbc , rc2-64-cbc, rc2-cbc, rc2-cfb, rc2-ecb , rc2-ofb, rc4, and rc4-40. By default, syslog-ng PE uses the aes-128-cbc method.

Note that the size of the digest hash must be equal to or larger than the key size of the cipher method. For example, to use the aes-256-cbc cipher method, the digest method must be at least SHA-256.

chunk-size()
Type: number (kilobytes)
Default: 128

Description: This option is obsolete. Use the journal-block-size() option instead.

Size of a logstore chunk in kilobytes. Note that this size refers to the compressed size of the chunk. Also, the gzip library used for compressing the messages has a 32k long buffer, so messages may not appear in the actual logfile until this buffer is not filled. Logstore chunks are closed when they reach the specified size, or when the time limit set in chunk-time() expires.

chunk-time()
Type: number (seconds)
Default: 5

Description: This option is obsolete.

Time limit in seconds: syslog-ng PE closes the chunk if no new messages arrive until the time limit expires. Logstore chunks are closed when the time limit expires, or when they reach the size specified in the chunk-size() parameter. If the time limit set in the time-reap() parameter expires, the entire file is closed.

compress()
Type: number (between 0-9)
Default: 3

Description: Compression level. 0 means uncompressed files, while 1-9 is the compression level used by gzip (9 means the highest but slowest compression, 3 is usually a good compromise).

create-dirs()
Type: yes or no
Default: no

Description: Enable creating non-existing directories when creating files or socket files.

digest()
Type: string
Default: SHA1

Description: Set the digest method to use. The following digest methods are available: MD4, MD5, SHA0 (SHA), SHA1, RIPEMD160, SHA224, SHA256, SHA384, and SHA512. By default, syslog-ng PE uses the SHA1 method.

Note that the size of the digest hash must be equal to or larger than the key size of the cipher method. For example, to use the aes-256-cbc cipher method, the digest method must be at least SHA256.

dir-group()
Type: string
Default: Use the global settings

Description: The group of the directories created by syslog-ng. To preserve the original properties of an existing directory, use the option without specifying an attribute: dir-group().

dir-owner()
Type: string
Default: Use the global settings

Description: The owner of the directories created by syslog-ng. To preserve the original properties of an existing directory, use the option without specifying an attribute: dir-owner().

Starting with version 7.0.9, the default value of this option is -1, so syslog-ng PE does not change the ownership, unless explicitly configured to do so.

dir-perm()
Type: number
Default: Use the global settings

Description: The permission mask of directories created by syslog-ng. Log directories are only created if a file after macro expansion refers to a non-existing directory, and directory creation is enabled (see also the create-dirs() option). For octal numbers prefix the number with 0, for example, use 0755 for rwxr-xr-x.

To preserve the original properties of an existing directory, use the option without specifying an attribute: dir-perm(). Note that when creating a new directory without specifying attributes for dir-perm(), the default permission of the directories is masked with the umask of the parent process (typically 0022).

encrypt-certificate()
Type: filename
Default: none

Description: Name of a file, that contains an X.509 certificate (and the public key) in PEM format. The syslog-ng PE application uses this certificate to encrypt the logstore files which can be decrypted using the private key of the certificate.

flags()
Type: serialized
Default: empty set

Description: Flags influence the behavior of the destination driver.

  • The serialized flag instructs the driver to store the log messages in a serialized format. When using the lgstool utility to display messages from the logstore, the messages can be reformatted with a template only if the serialized flag has been enabled on the logstore.

frac-digits()
Type: number
Default: 0

Description: The syslog-ng PE application can store fractions of a second in the timestamps according to the ISO8601 format. The frac-digits() parameter specifies the number of digits stored. The digits storing the fractions are padded by zeros if the original timestamp of the message specifies only seconds. Fractions can always be stored for the time the message was received.

NOTE: The syslog-ng PE application can add the fractions to non-ISO8601 timestamps as well.

NOTE: As syslog-ng PE is precise up to the microsecond, when the frac-digits() option is set to a value higher than 6, syslog-ng PE will truncate the fraction seconds in the timestamps after 6 digits.

group()
Type: string
Default: Use the global settings

Description: Set the group of the created file to the one specified. To preserve the original properties of an existing file, use the option without specifying an attribute: group().

log-fifo-size()
Type: number
Default: Use global setting.

Description: The number of messages that the output queue can store.

journal-block-count()
Type: number (1-255)
Default: 4

Description: The number of blocks in the journal file. If set to 0, syslog-ng will set it to the default value (4). The maximal value is 255. If journal-block-count() is set higher than 255, syslog-ng will use the maximum value.

NOTE: By default, journal files are mapped into the memory of the host. To influence the amount of memory addresses used by journal files, see the logstore-journal-shmem-threshold() global option.

Example: Setting journal block number and size

The following example sets the size of a journal block to 512KB and increases the number of blocks to 5.

destination d_logstore {
    logstore("/var/log/messages-logstore.lgs"
        encrypt-certificate ("/opt/syslog-ng/etc/syslog-ng/keys/public-server-certificate.pem")
        journal-block-size(524288)
        journal-block-count(5)
    );
};
journal-block-size()
Type: number (bytes)
Default: 1048576

Description: The size of blocks (in bytes) in the journal file. The size of the block must be a multiple of the page size: if not, syslog-ng PE automatically increases it to the next multiple of the page size. The maximum size of a journal block is 32MB, the minimum size is 256KB. If the value specified as journal-block-size() is lower than minimum size or higher than the maximum size, syslog-ng PE will use the minimum or maximum size, respectively.

NOTE: In addition, consider the following:

  • At least one journal block for every logstore file open is mapped into the memory. For details on logstore journals, see Journal files.

  • The size of the journal block is not equal with the size of logstore chunks, because the records in the logstore file can be encrypted or compressed.

Example: Setting journal block number and size

The following example sets the size of a journal block to 512KB and increases the number of blocks to 5.

destination d_logstore {
    logstore("/var/log/messages-logstore.lgs"
        encrypt-certificate ("/opt/syslog-ng/etc/syslog-ng/keys/public-server-certificate.pem")
        journal-block-size(524288)
        journal-block-count(5)
    );
};
owner()
Type: string
Default: Use the global settings

Description: Set the owner of the created file to the one specified. To preserve the original properties of an existing file, use the option without specifying an attribute: owner().

perm()
Type: number
Default: Use the global settings

Description: The permission mask of the file if it is created by syslog-ng. For octal numbers prefix the number with 0, for example, use 0755 for rwxr-xr-x.

To preserve the original properties of an existing file, use the option without specifying an attribute: perm().

template()
Type: string
Default: A format conforming to the default logfile format.

Description: Specifies a template defining the logformat to be used in the destination. Macros are described in Macros of syslog-ng PE. Please note that for network destinations it might not be appropriate to change the template as it changes the on-wire format of the syslog protocol which might not be tolerated by stock syslog receivers (like syslogd or syslog-ng itself). For network destinations make sure the receiver can cope with the custom format defined.

throttle()
Type: number
Default: 0

Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using the disk-buffer option as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.

timestamp-freq()
Type: number (seconds)
Default: Use global setting.

Description: The minimum time (in seconds) that should expire between two timestamping requests. When syslog-ng closes a chunk, it checks how much time has expired since the last timestamping request: if it is higher than the value set in the timestamp-freq() parameter, it requests a new timestamp from the authority set in the timestamp-url() parameter.

By default, timestamping is disabled: the timestamp-freq() global option is set to 0. To enable timestamping, set it to a positive value.

timestamp-policy()
Type: string
Default:

Description: If the Timestamping Server has timestamping policies configured, specify the OID of the policy to use with this parameter. syslog-ng PE will include this ID in the timestamping requests sent to the TSA. This option is available in syslog-ng PE 3.1 and later.

timestamp-url()
Type: string
Default: Use global setting.

Description: The URL of the Timestamping Authority used to request timestamps to sign logstore chunks. Note that syslog-ng PE currently supports only Timestamping Authorities that conform to RFC3161 Internet X.509 Public Key Infrastructure Time-Stamp Protocol, other protocols like Microsoft Authenticode Timestamping are not supported.

time-zone()
Type: name of the timezone, or the timezone offset
Default: unspecified

Description: Convert timestamps to the timezone specified by this option. If this option is not set, then the original timezone information in the message is used. Converting the timezone changes the values of all date-related macros derived from the timestamp, for example, HOUR. For the complete list of such macros, see Date-related macros.

The timezone can be specified as using the name of the (for example, time-zone("Europe/Budapest")), or as the timezone offset in +/-HH:MM format (for example, +01:00). On Linux and UNIX platforms, the valid timezone names are listed under the /usr/share/zoneinfo directory.

ts-format()
Type: rfc3164, bsd, rfc3339, iso
Default: rfc3164

Description: Override the global timestamp format (set in the global ts-format() parameter) for the specific destination. For details, see ts-format().

mongodb: Storing messages in a MongoDB database

The mongodb() driver sends messages to a MongoDB database. MongoDB is a schema-free, document-oriented database. For the list of available optional parameters, see mongodb() destination options.

NOTE: To use this destination, syslog-ng Premium Edition (syslog-ng PE) must run in server mode. Typically, only the central syslog-ng PE server uses this destination. For more information on the server mode, see Server mode.

Declaration
mongodb(parameters);

The mongodb() driver does not support creating indexes, as that can be a very complex operation in MongoDB. If needed, the administrator of the MongoDB database must ensure that indexes are created on the collections.

The mongodb() driver does not add the _id field to the message: the MongoDB server will do that automatically, if none is present. If you want to override this field from syslog-ng PE, use the key() parameter of the value-pairs() option.

The syslog-ng PE mongodb() driver is compatible with MongoDB server version 1.4 and newer.

NOTE: By default, syslog-ng PE handles every message field as a string. For details on how to send selected fields as other types of data (for example, handle the PID as a number), see Specifying data types in value-pairs.

Example: Using the mongodb() driver

The following example creates a mongodb() destination using only default values.

destination d_mongodb {
    mongodb();
};

The following example displays the default values.

destination d_mongodb {
    mongodb(
        uri("mongodb://localhost:27017/syslog")
        collection("messages")
        value-pairs(
            scope("selected-macros" "nv-pairs" "sdata")
        )
    );
};

The following example shows the same setup using the deprecated libmongo-client syntax, and is equivalent with the previous example.

destination d_mongodb {
    mongodb(
        servers("localhost:27017")
        database("syslog")
        collection("messages")
        value-pairs(
            scope("selected-macros" "nv-pairs" "sdata")
        )
    );
};

How syslog-ng PE connects the MongoDB server

When syslog-ng PE connects the MongoDB server during startup, it completes the following steps.

  1. The syslog-ng PE application connects the first address listed in the servers() option.

    • If the server is accessible and it is a master MongoDB server, syslog-ng PE authenticates on the server (if needed), then starts sending the log messages to the server.

    • If the server is not accessible, or it is not a master server in a MongoDB replicaset and it does not send the address of the master server, syslog-ng PE connects the next address listed in the servers() option.

    • If the server is not a master server in a MongoDB replicaset, but it sends the address of the master server, syslog-ng PE connects the received address.

  2. When syslog-ng PE connects the master MongoDB server, it retrieves the list of replicas (from the replSet option of the server), and appends this list to the servers() option.

    Caution:
    • This means that syslog-ng PE can send log messages to addresses that are not listed in its configuration.

    • Make sure to include the address of your master server in your syslog-ng PE configuration file, otherwise you risk losing log messages if all the addresses listed in the syslog-ng PE configuration are offline.

    • Addresses retrieved from the MongoDB servers are not stored, and can be lost when syslog-ng PE is restarted. The retrieved addresses are not lost if the server() option of the destination was not changed in the configuration file since the last restart.

    • The failover mechanism used in the mongodb() driver is different from the client-side failover used in other drivers.

  3. The syslog-ng PE application attempts to connect another server if the servers() list contains at least two addresses, and one of the following events happens:

    • The safe-mode() option is set to no, and the MongoDB server becomes unreachable.

    • The safe-mode() option is set to yes, and syslog-ng PE cannot insert a log message into the database because of an error.

    In this case, syslog-ng PE starts to connect the addresses in from the servers() list (starting from the first address) to find the new master server, authenticates on the new server (if needed), then continues to send the log messages to the new master server.

    During this failover step, one message can be lost if the safe-mode() option is disabled.

  4. If the original master becomes accessible again, syslog-ng PE will automatically connect to the original master.

mongodb() destination options

The mongodb() driver sends messages to a MongoDB database. MongoDB is a schema-free, document-oriented database.

NOTE: To use this destination, syslog-ng Premium Edition (syslog-ng PE) must run in server mode. Typically, only the central syslog-ng PE server uses this destination. For more information on the server mode, see Server mode.

The mongodb() destination has the following options:

bulk()
Type: yes|no
Default: yes

Description: Toggles bulk insertion, setting to no forces the old behavior (each log is inserted one by one into the MongoDB).

NOTE: Bulk sending is only efficient if the used collection is constant (e.g. not using templates) or the used template does not lead to too many collections switching within a reasonable time range.

bulk_unordered()
Type: yes|no
Default: no

Description: Toggles unordered bulk operations.

bulk_bypass_validation()
Type: yes|no
Default: no

Description: Toggles MongoDB bulk operation validation.

collection()
Type: string
Default: messages

Description: The name of the MongoDB collection where the log messages are stored (collections are similar to SQL tables). The collection() option supports template functions and macros as well.

Example: using the mongodb() destination with a template embedded in the collection() option

Using the following example configuration, the mongodb() destination sends incoming messages into separate MongoDB collections (for example, localhost_messages and anotherhost_messages) based on the HOST field of the message :

mongodb( uri("mongodb://host/syslog?wtimeoutMS=10000&socketTimeoutMS=10000&connectTimeoutMS=10000&serverSelectionTimeoutMS=5000") collection("${HOST}_messages") workers(8) );

Caution:

Hazard of data loss! The syslog-ng PE application does not verify that the specified collection name does not contain invalid characters. If you specify a collection with an invalid name, the log messages sent to the MongoDB database will be irrevocably lost without any warning.

disk-buffer()

Description: This option enables putting outgoing messages into the disk-buffer file of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:

dir()
Type: string
Default: N/A

Description: Defines the folder where the disk-buffer files are stored.

Note that changing the value the dir() option will not move or copy existing files from the old directory to the new one.

Caution:

When creating a new dir() option for a disk-buffer file, or modifying an existing one, make sure you delete the persist file.

syslog-ng PE creates disk-buffer files based on the path recorded in the persist file. Therefore, if the persist file is not deleted after modifying the dir() option, then following a restart, syslog-ng PE will look for or create disk-buffer files in their old location. To ensure that syslog-ng PE uses the new dir() setting, the persist file must not contain any information about the destinations which the disk-buffer file in question belongs to.

disk-buf-size()
Type: number [bytes]
Default:

Description: This is a required option. The maximum size of the disk-buffer file in bytes. The minimum value is 1048576 bytes. If you set a smaller value, the minimum value will be used automatically. It replaces the old log-disk-fifo-size() option.
mem-buf-length()
Type: number [messages]
Default: 10000
Description: Use this option if the option reliable() is set to no. This option contains the number of messages stored in overflow queue. It replaces the old log-fifo-size() option. It inherits the value of the global log-fifo-size() option if provided. If it is not provided, the default value is 10000 messages. Note that this option will be ignored if the option reliable() is set to yes.
mem-buf-size()
Type: number [bytes]
Default: 163840000
Description: Use this option if the option reliable() is set to yes. This option contains the size of the messages in bytes that is used in the memory part of the disk-buffer file. It replaces the old log-fifo-size() option. It does not inherit the value of the global log-fifo-size() option, even if it is provided. Note that this option will be ignored if the option reliable() is set to no.
quot-size()
Type: number [messages]
Default: 1000

Description: The number of messages stored in the output buffer of the destination. Note that if you change the value of this option and the disk-buffer file already exists, the change will take effect when the disk-buffer file becomes empty.

reliable()
Type: yes|no
Default: no

Description: If set to yes, syslog-ng PE cannot lose logs in case of reload/restart, unreachable destination or syslog-ng PE crash. This solution provides a slower, but reliable disk-buffer option. It is created and initialized at startup and gradually grows as new messages arrive. If set to no, the normal disk-buffer option will be used. This provides a faster, but less reliable disk-buffer option.

Caution: Hazard of data loss!

If you change the value of reliable() option when there are messages in the disk-buffer file, the messages stored in the disk-buffer file will be lost.

truncate-size-ratio()
Type: number (for percentage) between 0 and 1
Default: 0.1 (10%)

Description: Limits the truncation of the disk-buffer file. Truncating the disk-buffer file can slow down disk I/O operations, but it saves disk space. As a result, syslog-ng PE only truncates the file if the possible disk gain is more than truncate-size-ratio() times disk-buf-size().

Caution:

One Identity recommends that you do not modify the value of the truncate-size-ratio() option unless you are fully aware of the potential performance implications.

Example: Examples for using disk-buffer()

In the following case, reliable disk-buffer() is used.

destination d_demo {
    network("127.0.0.1"
        port(3333)
        disk-buffer(
            mem-buf-size(10000)
            disk-buf-size(2000000)
            reliable(yes)
            dir("/tmp/disk-buffer")
        )
    );
};

In the following case normal disk-buffer() is used.

destination d_demo {
    network("127.0.0.1"
        port(3333)
        disk-buffer(
            mem-buf-length(10000)
            disk-buf-size(2000000)
            reliable(no)
            dir("/tmp/disk-buffer")
        )
    );
};
frac-digits()
Type: number
Default: 0

Description: The syslog-ng PE application can store fractions of a second in the timestamps according to the ISO8601 format. The frac-digits() parameter specifies the number of digits stored. The digits storing the fractions are padded by zeros if the original timestamp of the message specifies only seconds. Fractions can always be stored for the time the message was received.

NOTE: The syslog-ng PE application can add the fractions to non-ISO8601 timestamps as well.

NOTE: As syslog-ng PE is precise up to the microsecond, when the frac-digits() option is set to a value higher than 6, syslog-ng PE will truncate the fraction seconds in the timestamps after 6 digits.

local-time-zone()
Type: name of the timezone, or the timezone offset
Default: The local timezone.

Description: Sets the timezone used when expanding filename and tablename templates.

The timezone can be specified as using the name of the (for example, time-zone("Europe/Budapest")), or as the timezone offset in +/-HH:MM format (for example, +01:00). On Linux and UNIX platforms, the valid timezone names are listed under the /usr/share/zoneinfo directory.

log-fifo-size()
Type: number
Default: Use global setting.

Description: The number of messages that the output queue can store.

on-error()
Accepted values:

drop-message|drop-property|fallback-to-string|

silently-drop-message|silently-drop-property|silently-fallback-to-string

Default: Use the global setting (which defaults to drop-message)

Description: Controls what happens when type-casting fails and syslog-ng PE cannot convert some data to the specified type. By default, syslog-ng PE drops the entire message and logs the error. Currently the value-pairs() option uses the settings of on-error().

  • drop-message: Drop the entire message and log an error message to the internal() source. This is the default behavior of syslog-ng PE.

  • drop-property: Omit the affected property (macro, template, or message-field) from the log message and log an error message to the internal() source.

  • fallback-to-string: Convert the property to string and log an error message to the internal() source.

  • silently-drop-message: Drop the entire message silently, without logging the error.

  • silently-drop-property: Omit the affected property (macro, template, or message-field) silently, without logging the error.

  • silently-fallback-to-string: Convert the property to string silently, without logging the error.

retries()
Type: number [of attempts]
Default: 3

Description: The number of times syslog-ng PE attempts to send a message to this destination. If syslog-ng PE could not send a message, it will try again until the number of attempts reaches retries(), then drops the message.

For MongoDB operations, syslog-ng PE uses a one-minute timeout: if an operation times out, syslog-ng PE assumes the operation has failed.

throttle()
Type: number
Default: 0

Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using the disk-buffer option as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.

uri()
Type: string
Default: mongodb://127.0.0.1:27017/syslog?wtimeoutMS=60000&socketTimeoutMS=60000&connectTimeoutMS=60000

Description: Refer to the MongoDB URI format documentation for detailed syntax.

value-pairs()
Type: parameter list of the value-pairs() option
Default:
scope("selected-macros" "nv-pairs")

Description: The value-pairs() option creates structured name-value pairs from the data and metadata of the log message. For details on using value-pairs(), see Structuring macros, metadata, and other value-pairs.

NOTE: Empty keys are not logged.

NOTE: By default, syslog-ng PE handles every message field as a string. For details on how to send selected fields as other types of data (for example, handle the PID as a number), see Specifying data types in value-pairs.

workers()
Type: integer
Default: 1

Description: Specifies the number of worker threads (at least 1) that syslog-ng PE uses to send messages to the server. Increasing the number of worker threads can drastically improve the performance of the destination.

Caution:

Hazard of data loss!

When you use more than one worker threads together with the disk-buffer option, syslog-ng PE creates a separate disk-buffer file for each worker thread. This means that decreasing the number of workers can result in losing data currently stored in the disk-buffer files. Do not decrease the number of workers when the disk-buffer files are in use.

write_concern()
Accepted values:

unacked|acked|majority|a number greater than 0

Default: acked

Description: Sets write concern mode of MongoDB operations, both bulk and single.

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