The collectd() destination uses the unixsock plugin of the collectd application to send log messages to the collectd system statistics collection daemon. You must install and configure collectd separately before using this destination.
Available in syslog-ng OSE version 3.20 and later.
Declaration:
collectd();
destination d_collectd {
collectd(
socket("<path-to-collectd-socket>"),
host("${HOST}"),
plugin("${PROGRAM}"),
type("<type-of-the-collected-metric>"),
values("<metric-sent-to-collectd>"),
);
};
Example: Using the collectd() driver
The following example uses the name of the application sending the log message as the plugin name, and the value of the ${SEQNUM} macro as the value of the metric sent to collectd.
destination d_collectd {
collectd(
socket("/var/run/collectd-unixsock"),
host("${HOST}"),
plugin("${PROGRAM}"),
type("gauge"),
type_instance("seqnum"),
values("${SEQNUM}"),
);
};
To use the collectd() driver, the scl.conf file must be included in your syslog-ng OSE configuration:
@include "scl.conf"
The collectd() driver is actually a reusable configuration snippet configured to send log messages using the unix-stream() driver. For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find the source of this configuration snippet on GitHub.
The collectd() destination has the following options. The plugin() and type() options are required options. You can also set other options of the underlying unix-stream() driver (for example, socket buffer size).
disk-buffer()
Description: This option enables putting outgoing messages into the disk buffer of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:
| reliable() |
| Type: |
yes|no |
| Default: |
no |
|
Description: If set to yes, syslog-ng OSE cannot lose logs in case of reload/restart, unreachable destination or syslog-ng OSE 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 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, the messages stored in the disk-buffer will be lost. | |
| compaction() |
| Type: |
yes|no |
| Default: |
no |
|
Description: If set to yes, syslog-ng OSE prunes the unused space in the LogMessage representation, making the disk queue size smaller at the cost of some CPU time. Setting the compaction() argument to yes is recommended when numerous name-value pairs are unset during processing, or when the same names are set multiple times. |
NOTE: Simply unsetting these name-value pairs by using the unset() rewrite operation is not enough, as due to performance reasons that help when syslog-ng OSE is CPU bound, the internal representation of a LogMessage will not release the memory associated with these name-value pairs. In some cases, however, the size of this overhead becomes significant (the raw message size can grow up to four times its original size), which unnecessarily increases the disk queue file size. For these cases, the compaction will drop unset values, making the LogMessage representation smaller at the cost of some CPU time required to perform compaction.
| dir() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the folder where the disk-buffer files are stored.
|
|
Caution:
When creating a new dir() option for a disk buffer, or modifying an existing one, make sure you delete the persist file.
syslog-ng OSE 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 OSE will look for or create disk-buffer files in their old location. To ensure that syslog-ng OSE 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. |
NOTE: If the dir() path provided by the user does not exist, syslog-ng OSE creates the path with the same permission as the running instance. |
| disk-buf-size() |
| Type: |
number (bytes) |
| Default: |
|
| Description: This is a required option. The maximum size of the disk-buffer 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. 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. |
| qout-size() |
| Type: |
number (messages) |
| Default: |
64 |
| 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 already exists, the change will take effect when the disk-buffer becomes empty. |
Options reliable() and disk-buf-size() are required options.
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")
)
);
};
|
truncate-size-ratio() |
| Type: |
number (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 the disk IO operations, but it saves disk space, so syslog-ng only truncates the file, if the possible disk gain is more than truncate-size-ratio() times disk-buf-size().
|
|
Caution:
One Identity does not recommend you to change truncate-size-ratio(). Only change its value if you know the performance implications of doing so. | |
flush-lines()
| Type: |
number |
| Default: |
Use global setting (exception: for http() destination, the default is 1). |
Description: Specifies how many lines are flushed to a destination at a time. The syslog-ng OSE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.
The syslog-ng OSE application flushes the messages if it has sent flush-lines() number of messages, or the queue became empty. If you stop or reload syslog-ng OSE or in case of network sources, the connection with the client is closed, syslog-ng OSE automatically sends the unsent messages to the destination.
For optimal performance when sending messages to an syslog-ng OSE server, make sure that the value of flush-lines() is smaller than the window size set in the log-iw-size() option in the source of your server.
Description: The syslog-ng 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 OSE application can add the fractions to non-ISO8601 timestamps as well.
NOTE: As syslog-ng OSE is precise up to the microsecond, when the frac-digits() option is set to a value higher than 6, syslog-ng OSE will truncate the fraction seconds in the timestamps after 6 digits.
hook-commands()
Description: This option makes it possible to execute external programs when the relevant driver is initialized or torn down. The hook-commands() can be used with all source and destination drivers with the exception of the usertty() and internal() drivers.
NOTE: The syslog-ng OSE application must be able to start and restart the external program, and have the necessary permissions to do so. For example, if your host is running AppArmor or SELinux, you might have to modify your AppArmor or SELinux configuration to enable syslog-ng OSE to execute external applications.
Using the hook-commands() when syslog-ng OSE starts or stops
To execute an external program when syslog-ng OSE starts or stops, use the following options:
| startup() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the external program that is executed as syslog-ng OSE starts. |
| shutdown() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the external program that is executed as syslog-ng OSE stops. |
Using the hook-commands() when syslog-ng OSE reloads
To execute an external program when the syslog-ng OSE configuration is initiated or torn down, for example, on startup/shutdown or during a syslog-ng OSE reload, use the following options:
| setup() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines an external program that is executed when the syslog-ng OSE configuration is initiated, for example, on startup or during a syslog-ng OSE reload. |
| teardown() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines an external program that is executed when the syslog-ng OSE configuration is stopped or torn down, for example, on shutdown or during a syslog-ng OSE reload. |
Example: Using the hook-commands() with a network source
In the following example, the hook-commands() is used with the network() driver and it opens an iptables port automatically as syslog-ng OSE is started/stopped.
The assumption in this example is that the LOGCHAIN chain is part of a larger ruleset that routes traffic to it. Whenever the syslog-ng OSE created rule is there, packets can flow, otherwise the port is closed.
source {
network(transport(udp)
hook-commands(
startup("iptables -I LOGCHAIN 1 -p udp --dport 514 -j ACCEPT")
shutdown("iptables -D LOGCHAIN 1")
)
);
};
host()
| Type: |
string, macro, or template |
| Default: |
${HOST} |
Description: The hostname that is passed to collectd. By default, syslog-ng OSE uses the host from the log message as the hostname.
type("gauge"),
interval()
| Type: |
integer |
| Default: |
60 |
Description: The interval in which the data is collected.
log-fifo-size()
| Type: |
number |
| Default: |
Use global setting. |
Description: The number of messages that the output queue can store.
keep-alive()
| Type: |
yes or no |
| Default: |
yes |
Description: Specifies whether connections to destinations should be closed when syslog-ng is reloaded. Note that this applies to the client (destination) side of the syslog-ng connections, server-side (source) connections are always reopened after receiving a HUP signal unless the keep-alive option is enabled for the source.
plugin()
Description: The name of the plugin that submits the data to collectd. For example:
plugin("${PROGRAM}"),
plugin-instance()
Description: The name of the plugin-instance that submits the data to collectd.
socket()
| Type: |
path |
| Default: |
/var/run/collectd-unixsock |
Description: The path to the socket of collectd. For details, see the collectd-unixsock(5) manual page.
type("gauge"),
so-broadcast()
| Type: |
yes or no |
| Default: |
no |
Description: This option controls the SO_BROADCAST socket option required to make syslog-ng send messages to a broadcast address. For details, see the socket(7) manual page.
so-keepalive()
| Type: |
yes or no |
| Default: |
no |
Description: Enables keep-alive messages, keeping the socket open. This only effects TCP and UNIX-stream sockets. For details, see the socket(7) manual page.
so-rcvbuf()
Description: Specifies the size of the socket receive buffer in bytes. For details, see the socket(7) manual page.
so-sndbuf()
Description: Specifies the size of the socket send buffer in bytes. For details, see the socket(7) manual page.
suppress()
| Type: |
seconds |
| Default: |
0 (disabled) |
Description: If several identical log messages would be sent to the destination without any other messages between the identical messages (for example, an application repeated an error message ten times), syslog-ng can suppress the repeated messages and send the message only once, followed by the Last message repeated n times. message. The parameter of this option specifies the number of seconds syslog-ng waits for identical messages.
throttle()
Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using disk-buffer as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.
type()
| Type: |
string or template |
| Default: |
|
Description: Identifies the type and number of values passed to collectd. For details, see the types.db manual page. For example:
type("gauge"),
type-instance()
Description: For example:
type-instance("seqnum"),
values()
| Type: |
string, macro,or template |
| Default: |
U |
Description: Colon-separated list of the values to send to collectd. For example:
values("${SEQNUM}"),
The discord() destination driver sends messages to Discord using Discord Webhook. For the list of available optional parameters, see Discord destination options.
Available in syslog-ng OSE version 3.33 and later.
Declaration:
destination {
discord(url("https://discord.com/api/webhooks/x/y"));
};
By default the message sending is throttled to 5 message/sec, see Discord: Rate Limits. To change this, use the throttle() option.
To use this destination, the scl.conf file must be included in your syslog-ng OSE configuration:
@include "scl.conf"
The discord() driver is actually a reusable configuration snippet configured to send log messages using the http() driver. For details on using or writing such configuration snippets, see Reusing configuration blocks. You can find the source of this configuration snippet on GitHub.
Example: Using the discord() driver
The following example sends messages with custom avatar, and text-to-speech enabled.
@include "scl.conf"
destination d_discord {
discord(
url("https://discord.com/api/webhooks/x/y")
avatar-url("https://example.domain/any_image.png")
username("$HOST-bot") # Custom bot name, accepts macros
tts(true) # Text-to-Speech message
template("${MSG:-[empty message]}") # Message to send, can't be empty
);
ó}
The discord() destination of syslog-ng OSE can directly post log messages to web services using the HTTP protocol. The discord() destination has the following options.
avatar-url()
Description: A hyperlink for icon of the author to be displayed in Discord. For details, see the avatar_url option in the Discord documentation.
batch-bytes()
| Accepted values: |
number [bytes] |
| Default: |
none |
Description: Sets the maximum size of payload in a batch. If the size of the messages reaches this value, syslog-ng OSE sends the batch to the destination even if the number of messages is less than the value of the batch-lines() option.
Note that if the batch-timeout() option is enabled and the queue becomes empty, syslog-ng OSE flushes the messages only if batch-timeout() expires, or the batch reaches the limit set in batch-bytes().
Available in syslog-ng OSE version 3.19 and later.
For details on how this option influences HTTP batch mode, see http: Posting messages over HTTP without Java
batch-lines()
Description: Specifies how many lines are flushed to a destination in one batch. The syslog-ng OSE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.
For example, if you set batch-lines() to 100, syslog-ng OSE waits for 100 messages.
If the batch-timeout() option is disabled, the syslog-ng OSE application flushes the messages if it has sent batch-lines() number of messages, or the queue became empty. If you stop or reload syslog-ng OSE or in case of network sources, the connection with the client is closed, syslog-ng OSE automatically sends the unsent messages to the destination.
Note that if the batch-timeout() option is enabled and the queue becomes empty, syslog-ng OSE flushes the messages only if batch-timeout() expires, or the batch reaches the limit set in batch-lines().
For optimal performance, make sure that the syslog-ng OSE source that feeds messages to this destination is configured properly: the value of the log-iw-size() option of the source must be higher than the batch-lines()*workers() of the destination. Otherwise, the size of the batches cannot reach the batch-lines() limit.
For details on how this option influences HTTP batch mode, see http: Posting messages over HTTP without Java
batch-timeout()
| Type: |
time in milliseconds |
| Default: |
none |
Description: Specifies the time syslog-ng OSE waits for lines to accumulate in the output buffer. The syslog-ng OSE application sends batches to the destinations evenly. The timer starts when the first message arrives to the buffer, so if only few messages arrive, syslog-ng OSE sends messages to the destination at most once every batch-timeout() milliseconds.
For details on how this option influences HTTP batch mode, see http: Posting messages over HTTP without Java
ca-dir()
| Accepted values: |
Directory name |
| Default: |
none |
Description: The name of a directory that contains a set of trusted CA certificates in PEM format. The CA certificate files have to be named after the 32-bit hash of the subject's name. This naming can be created using the c_rehash utility in openssl. For an example, see Configuring TLS on the syslog-ng clients. The syslog-ng OSE application uses the CA certificates in this directory to validate the certificate of the peer.
This option can be used together with the optional ca-file() option.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. In case you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration:
destination d_http {
http(
url("http://127.0.0.1:8080")
tls(
ca-dir("dir")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
cert-file()
| Accepted values: |
Filename |
| Default: |
none |
Description: Name of a file, that contains an X.509 certificate (or a certificate chain) in PEM format, suitable as a TLS certificate, matching the private key set in the key-file() option. The syslog-ng OSE application uses this certificate to authenticate the syslog-ng OSE client on the destination server. If the file contains a certificate chain, the file must begin with the certificate of the host, followed by the CA certificate that signed the certificate of the host, and any other signing CAs in order.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. In case you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration:
destination d_http {
http(
url("http://127.0.0.1:8080")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
cipher-suite()
| Accepted values: |
Name of a cipher, or a colon-separated list |
| Default: |
Depends on the OpenSSL version that syslog-ng OSE uses |
Description: Specifies the cipher, hash, and key-exchange algorithms used for the encryption, for example, ECDHE-ECDSA-AES256-SHA384. The list of available algorithms depends on the version of OpenSSL used to compile syslog-ng OSE. To specify multiple ciphers, separate the cipher names with a colon, and enclose the list between double-quotes, for example:
cipher-suite("ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384")
For a list of available algorithms, execute the openssl ciphers -v command. The first column of the output contains the name of the algorithms to use in the cipher-suite() option, the second column specifies which encryption protocol uses the algorithm (for example, TLSv1.2). That way, the cipher-suite() also determines the encryption protocol used in the connection: to disable SSLv3, use an algorithm that is available only in TLSv1.2, and that both the client and the server supports. You can also specify the encryption protocols using ssl-options().
You can also use the following command to automatically list only ciphers permitted in a specific encryption protocol, for example, TLSv1.2:
echo "cipher-suite(\"$(openssl ciphers -v | grep TLSv1.2 | awk '{print $1}' | xargs echo -n | sed 's/ /:/g' | sed -e 's/:$//')\")"
Note that starting with version 3.10, when syslog-ng OSE receives TLS-encrypted connections, the order of ciphers set on the syslog-ng OSE server takes precedence over the client settings.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. In case you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration:
destination d_http {
http(
url("http://127.0.0.1:8080")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
disk-buffer()
Description: This option enables putting outgoing messages into the disk buffer of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:
| reliable() |
| Type: |
yes|no |
| Default: |
no |
|
Description: If set to yes, syslog-ng OSE cannot lose logs in case of reload/restart, unreachable destination or syslog-ng OSE 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 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, the messages stored in the disk-buffer will be lost. | |
| compaction() |
| Type: |
yes|no |
| Default: |
no |
|
Description: If set to yes, syslog-ng OSE prunes the unused space in the LogMessage representation, making the disk queue size smaller at the cost of some CPU time. Setting the compaction() argument to yes is recommended when numerous name-value pairs are unset during processing, or when the same names are set multiple times. |
NOTE: Simply unsetting these name-value pairs by using the unset() rewrite operation is not enough, as due to performance reasons that help when syslog-ng OSE is CPU bound, the internal representation of a LogMessage will not release the memory associated with these name-value pairs. In some cases, however, the size of this overhead becomes significant (the raw message size can grow up to four times its original size), which unnecessarily increases the disk queue file size. For these cases, the compaction will drop unset values, making the LogMessage representation smaller at the cost of some CPU time required to perform compaction.
| dir() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the folder where the disk-buffer files are stored.
|
|
Caution:
When creating a new dir() option for a disk buffer, or modifying an existing one, make sure you delete the persist file.
syslog-ng OSE 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 OSE will look for or create disk-buffer files in their old location. To ensure that syslog-ng OSE 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. |
NOTE: If the dir() path provided by the user does not exist, syslog-ng OSE creates the path with the same permission as the running instance. |
| disk-buf-size() |
| Type: |
number (bytes) |
| Default: |
|
| Description: This is a required option. The maximum size of the disk-buffer 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. 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. |
| qout-size() |
| Type: |
number (messages) |
| Default: |
64 |
| 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 already exists, the change will take effect when the disk-buffer becomes empty. |
Options reliable() and disk-buf-size() are required options.
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")
)
);
};
|
truncate-size-ratio() |
| Type: |
number (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 the disk IO operations, but it saves disk space, so syslog-ng only truncates the file, if the possible disk gain is more than truncate-size-ratio() times disk-buf-size().
|
|
Caution:
One Identity does not recommend you to change truncate-size-ratio(). Only change its value if you know the performance implications of doing so. | |
hook-commands()
Description: This option makes it possible to execute external programs when the relevant driver is initialized or torn down. The hook-commands() can be used with all source and destination drivers with the exception of the usertty() and internal() drivers.
NOTE: The syslog-ng OSE application must be able to start and restart the external program, and have the necessary permissions to do so. For example, if your host is running AppArmor or SELinux, you might have to modify your AppArmor or SELinux configuration to enable syslog-ng OSE to execute external applications.
Using the hook-commands() when syslog-ng OSE starts or stops
To execute an external program when syslog-ng OSE starts or stops, use the following options:
| startup() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the external program that is executed as syslog-ng OSE starts. |
| shutdown() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the external program that is executed as syslog-ng OSE stops. |
Using the hook-commands() when syslog-ng OSE reloads
To execute an external program when the syslog-ng OSE configuration is initiated or torn down, for example, on startup/shutdown or during a syslog-ng OSE reload, use the following options:
| setup() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines an external program that is executed when the syslog-ng OSE configuration is initiated, for example, on startup or during a syslog-ng OSE reload. |
| teardown() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines an external program that is executed when the syslog-ng OSE configuration is stopped or torn down, for example, on shutdown or during a syslog-ng OSE reload. |
Example: Using the hook-commands() with a network source
In the following example, the hook-commands() is used with the network() driver and it opens an iptables port automatically as syslog-ng OSE is started/stopped.
The assumption in this example is that the LOGCHAIN chain is part of a larger ruleset that routes traffic to it. Whenever the syslog-ng OSE created rule is there, packets can flow, otherwise the port is closed.
source {
network(transport(udp)
hook-commands(
startup("iptables -I LOGCHAIN 1 -p udp --dport 514 -j ACCEPT")
shutdown("iptables -D LOGCHAIN 1")
)
);
};
log-fifo-size()
| Type: |
number |
| Default: |
Use global setting. |
Description: The number of messages that the output queue can store.
key-file()
| Accepted values: |
Filename |
| Default: |
none |
Description: The name of a file that contains an unencrypted private key in PEM format, suitable as a TLS key. If properly configured, the syslog-ng OSE application uses this private key and the matching certificate (set in the cert-file() option) to authenticate the syslog-ng OSE client on the destination server.
The http() destination supports only unencrypted key files (that is, the private key cannot be password-protected).
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. In case you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration:
destination d_http {
http(
url("http://127.0.0.1:8080")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
max-msg-length()
| Type: |
Number |
| Default: |
2000 |
Description: Removes every character above the set limit. For details, see the content option in the Discord documentation.
peer-verify()
| Accepted values: |
yes | no |
| Default: |
yes |
Description: Verification method of the peer. The following table summarizes the possible options and their results depending on the certificate of the peer.
| Local peer-verify() setting |
no (optional-untrusted) |
TLS-encryption |
TLS-encryption |
TLS-encryption |
| yes (required-trusted) |
rejected connection |
rejected connection |
TLS-encryption |
For untrusted certificates only the existence of the certificate is checked, but it does not have to be valid — syslog-ng accepts the certificate even if it is expired, signed by an unknown CA, or its CN and the name of the machine mismatches.
|
|
Caution:
When validating a certificate, the entire certificate chain must be valid, including the CA certificate. If any certificate of the chain is invalid, syslog-ng OSE will reject the connection. |
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. In case you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
persist-name()
| Type: |
string |
| Default: |
N/A |
Description:If you receive the following error message during syslog-ng OSE startup, set the persist-name() option of the duplicate drivers:
Error checking the uniqueness of the persist names, please override it with persist-name option. Shutting down.
This error happens if you use identical drivers in multiple sources, for example, if you configure two file sources to read from the same file. In this case, set the persist-name() of the drivers to a custom string, for example, persist-name("example-persist-name1").
proxy()
| Type: |
The proxy server address, in proxy("PROXY_IP:PORT") format.
For example, proxy("http://myproxy:3128") |
| Default: |
None |
Description:
You can use the proxy() option to configure the HTTP driver in all HTTP-based destinations to use a specific HTTP proxy that is independent from the proxy configured for the system.
Alternatively, you can leave the HTTP as-is, in which case the driver leaves the default http_proxy and https_proxy environment variables unmodified.
NOTE: Configuring the proxy() option overwrites the default http_proxy and https_proxy environment variables.
Example: the proxy() option in configuration
The following example illustrates including the proxy() option in your configuration.
destination {
http( url("SYSLOG_SERVER_IP:PORT") proxy("PROXY_IP:PORT") method("POST"));
};
response-action()
| Type: |
list |
| Default: |
N/A (see below) |
Description: Specifies what syslog-ng OSE does with the log message, based on the response code received from the HTTP server. If the server returns a status code beginning with 2 (for example, 200), syslog-ng OSE assumes the message was successfully sent. Otherwise, the action listed in the following table is applied. For status codes not listed in the following table, if the status code begins with 2 (for example, 299), syslog-ng OSE assumes the message was successfully sent. For other status codes, syslog-ng OSE disconnects. The following actions are possible:
-
disconnect: Keep trying to resend the message indefinitely.
-
drop: Drop the message without trying to resend it.
-
retry: Retry sending the message for a maximum of retries() times (3 by default).
-
success: Assume the message was successfully sent.
|------+-----------------------------------+------------|
| code | explanation | action |
|------+-----------------------------------+------------|
| 100 | "Continue" | disconnect |
| 101 | "Switching Protocols" | disconnect |
| 102 | "Processing" | retry |
| 103 | "Early Hints" | retry |
| 200 | "OK" | success |
| 201 | "Created" | success |
| 202 | "Accepted" | success |
| 203 | "Non-Authoritative Information" | success |
| 204 | "No Content" | success |
| 205 | "Reset Content" | success |
| 206 | "Partial Content" | success |
| 300 | "Multiple Choices" | disconnect |
| 301 | "Moved Permanently" | disconnect |
| 302 | "Found" | disconnect |
| 303 | "See Other" | disconnect |
| 304 | "Not Modified" | retry |
| 307 | "Temporary Redirect" | disconnect |
| 308 | "Permanent Redirect" | disconnect |
| 400 | "Bad Request" | disconnect |
| 401 | "Unauthorized" | disconnect |
| 402 | "Payment Required" | disconnect |
| 403 | "Forbidden" | disconnect |
| 404 | "Not Found" | disconnect |
| 405 | "Method Not Allowed" | disconnect |
| 406 | "Not Acceptable" | disconnect |
| 407 | "Proxy Authentication Required" | disconnect |
| 408 | "Request Timeout" | disconnect |
| 409 | "Conflict" | disconnect |
| 410 | "Gone" | drop |
| 411 | "Length Required" | disconnect |
| 412 | "Precondition Failed" | disconnect |
| 413 | "Payload Too Large" | disconnect |
| 414 | "URI Too Long" | disconnect |
| 415 | "Unsupported Media Type" | disconnect |
| 416 | "Range Not Satisfiable" | drop |
| 417 | "Expectation Failed" | disconnect |
| 418 | "I'm a teapot" | disconnect |
| 421 | "Misdirected Request" | disconnect |
| 422 | "Unprocessable Entity" | drop |
| 423 | "Locked" | disconnect |
| 424 | "Failed Dependency" | drop |
| 425 | "Too Early" | drop |
| 426 | "Upgrade Required" | disconnect |
| 428 | "Precondition Required" | retry |
| 429 | "Too Many Requests" | disconnect |
| 431 | "Request Header Fields Too Large" | disconnect |
| 451 | "Unavailable For Legal Reasons" | drop |
| 500 | "Internal Server Error" | disconnect |
| 501 | "Not Implemented" | disconnect |
| 502 | "Bad Gateway" | disconnect |
| 503 | "Service Unavailable" | disconnect |
| 504 | "Gateway Timeout" | retry |
| 505 | "HTTP Version Not Supported" | disconnect |
| 506 | "Variant Also Negotiates" | disconnect |
| 507 | "Insufficient Storage" | disconnect |
| 508 | "Loop Detected" | drop |
| 510 | "Not Extended" | disconnect |
| 511 | "Network Authentication Required" | disconnect |
|------+-----------------------------------+------------|
To customize the action to take for a particular response code, use the following format: response-action(<response-code> => <action>. To customize multiple response code-action pairs, separate them with a comma, for example:
http(
url("http://localhost:8080")
response-action(418 => drop, 404 => retry)
);
retries()
| Type: |
number (of attempts) |
| Default: |
3 |
Description: If syslog-ng OSE cannot send a message, it will try again until the number of attempts reaches retries().
If the number of attempts reaches retries(), syslog-ng OSE will wait for time-reopen() time, then tries sending the message again.
To handle HTTP error responses, if the HTTP server returns 5xx codes, syslog-ng OSE will attempt to resend messages until the number of attempts reaches retries. If the HTTP server returns 4xx codes, syslog-ng OSE will drop the messages.
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 OSE. 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.
|
|
CAUTION: Hazard of data loss! Make sure to include a fallback value, as if the template gets resolved to an empty string, Discord rejects the message. |
throttle()
Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using disk-buffer as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.
For more information, see Discord: Rate Limits.
timeout()
| Type: |
number [seconds] |
| Default: |
0 |
Description: The value (in seconds) to wait for an operation to complete, and attempt to reconnect the server if exceeded. By default, the timeout value is 0, meaning that there is no timeout. Available in version 3.11 and later.
tts()
| Type: |
true | false |
| Default: |
false |
Description: Enables TTS (Text-To-Speech) mode. For more information, see the tts option in the Discord documentation.
user-agent()
| Type: |
string |
| Default: |
syslog-ng [version]/libcurl[version] |
Description: The value of the USER-AGENT header in the messages sent to the server.
username()
| Type: |
string |
| Default: |
N/A |
Description: Overrides the default username of the webhook. For details, see the username option in the Discord documentation.
use-system-cert-store()
| Type: |
yes | no |
| Default: |
no |
Description: Use the certificate store of the system for verifying HTTPS certificates. For details, see the curl documentation.
workers()
Description: Specifies the number of worker threads (at least 1) that syslog-ng OSE 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 disk-based buffering, syslog-ng OSE creates a separate disk buffer 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. |
If you are using load-balancing (that is, you have configured multiple servers in the url() option), increase the number of worker threads at least to the number of servers. For example, if you have set three URLs (url("site1", "site2", "site3")), set the workers() option to 3 or more.
