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")
)
);
};
When syslog-ng PE connects the MongoDB server during startup, it completes the following steps.
-
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.
-
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. |
-
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.
-
If the original master becomes accessible again, syslog-ng PE will automatically connect to the original master.
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:
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()
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()
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()
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. |
The network() destination driver can send syslog messages conforming to RFC3164 from the network using the TCP, TLS, and UDP networking protocols.
-
UDP is a simple datagram oriented protocol, which provides "best effort service" to transfer messages between hosts. It may lose messages, and no attempt is made to retransmit lost messages. The BSD-syslog protocol traditionally uses UDP.
Use UDP only if you have no other choice.
-
TCP provides connection-oriented service: the client and the server establish a connection, each message is acknowledged, and lost packets are resent. TCP can detect lost connections, and messages are lost, only if the TCP connection breaks. When a TCP connection is broken, messages that the client has sent but were not yet received on the server are lost.
-
The syslog-ng application supports TLS (Transport Layer Security, also known as SSL) over TCP. For details, see Encrypting log messages with TLS.
Declaration
network("<destination-address>" [options]);
The network() destination has a single required parameter that specifies the destination host address where messages should be sent. If name resolution is configured, you can use the hostname of the target server. By default, syslog-ng PE sends messages using the TCP protocol to port 514.
Example: Using the network() driver
TCP destination that sends messages to 10.1.2.3, port 1999:
destination d_tcp { network("10.1.2.3" port(1999)); };
If name resolution is configured, you can use the hostname of the target server as well.
destination d_tcp { network("target_host" port(1999)); };
TCP destination that sends messages to the ::1 IPv6 address, port 2222.
destination d_tcp6 {
network(
"::1"
port(2222)
transport(tcp)
ip-protocol(6)
);
};
To send messages using the IETF-syslog message format without using the IETF-syslog protocol, enable the syslog-protocol flag. (For details on how to use the IETF-syslog protocol, see syslog() destination options.)
destination d_tcp {
network("10.1.2.3"
port(1999)
flags(syslog-protocol)
);
};
