Raijin (om_raijin)

This module enables logs to be forwarded to Raijin Database servers for ingestion. It connects to the URL specified in the configuration in either HTTP or HTTPS mode. Raijin accepts HTTP POST requests with multiple JSON records in the request body, assuming that there is a target database table already created on the Raijin side. Although Raijin accepts structured data in flat JSON (i.e. a list of key-value pairs) format, it does not support JSON values comprised of nested data structures or other non-scalar data such as arrays and maps. Raijin currently does not support authorization/SSL but the om_raijin module supports TLS since TLS can be enabled with an HTTP proxy.

This module requires the xm_json extension module to be loaded to convert the payload to JSON. See the Output log format section for information on the format of the payload.

Output log format

om_raijin forwards log records over HTTP(S) as JSON payload. The JSON format depends on the value of the $raw_event field. The module checks if the value of $raw_event is valid JSON and applies the following rules:

If it is valid JSON, the value is forwarded as is.
If it is not valid JSON, the log record is converted to JSON in the following format:
```
{
  "raw_event": "<json_escaped_raw_event>"
}
```

Additional metadata, including the NXLog Agent-specific fields EventReceivedTime, SourceModuleName, and SourceModuleType, will not be included in the output unless these values have been written to the $raw_event field. The processing required to achieve this depends on the format of the input data, but generally it means you need to:

Parse the log record according to the data format.
- If the input data is already in JSON format, use parse_json() to parse $raw_event into fields.
- If the input is unstructured plain text data, copy the value of $raw_event to a custom field.
Create and populate any additional custom fields.
Use to_json() to convert the fields to JSON format and update the value of $raw_event.

See the Examples section for NXLog Agent configuration examples of the above.

Configuration

The om_raijin module accepts the following directives in addition to the common module directives.

Required directives

The following directives are required for the module to start.

DBName

This mandatory directive specifies the name of the Raijin database containing the table where logs will be stored.

DBTable

This mandatory directive specifies the name of the database table where log events will be inserted as JSON records.

URL

This mandatory directive is comprised of the REST API URI that Raijin Server uses for receiving bulk, JSON-formatted events via POST requests:

http://<RaijinServerHostname>:<port>

If an om_raijin module instance contains multiple URL directives, the hosts will function as a cluster in failover mode. This directive also supports HTTPS URLs. If the optional port number part of the URL (:<port>) is not explicitly included in the URL, it will default to port 80 for HTTP (or port 443 for HTTPS).

The Raijin Database REST API listens by default on port 2500. If you plan to use this directive without explicitly specifying a port number, make sure the Raijin Database server is configured to listen on the correct default port corresponding to this directive (either 80 or 443).

TLS/SSL directives

The following directives are for configuring secure data transfer via TLS/SSL.

HTTPSAllowUntrusted

Accepts a boolean value to determine whether the remote connection should be allowed without certificate verification. If set to TRUE, the connection will be allowed even if the remote HTTPS server presents an unknown or self-signed certificate. The default value is FALSE; the remote HTTPS server must present a trusted certificate.

HTTPBasicAuthUser

HTTP basic authorization username.

HTTPBasicAuthPassword

HTTP basic authorization password.

HTTP authorization works only when both HTTPBasicAuthUser and HTTPBasicAuthPassword parameters are set.

HTTPSCADir

This directive specifies a path to a directory containing certificate authority (CA) certificates. These certificates will be used to verify the certificate presented by the remote server. The certificate files must be named using the OpenSSL hashed format, i.e. the hash of the certificate followed by .0, .1 etc. To find the hash of a certificate using OpenSSL:

$ openssl x509 -hash -noout -in ca.crt

For example, if the certificate hash is e2f14e4a, then the certificate filename should be e2f14e4a.0. If there is another certificate with the same hash then it should be named e2f14e4a.1 and so on.

A remote server’s self-signed certificate (which is not signed by a CA) can also be trusted by including a copy of the certificate in this directory.

The default operating system root certificate store will be used if this directive is not specified. Unix-like operating systems commonly store root certificates in /etc/ssl/certs. Windows operating systems use the Windows Certificate Store, while macOS uses the Keychain Access Application as the default certificate store.

HTTPSCAFile

This specifies the path of the certificate authority (CA) certificate that will be used to verify the certificate presented by the remote server. A remote server’s self-signed certificate (which is not signed by a CA) can be trusted by specifying the remote server certificate itself. In the case of certificates signed by an intermediate CA, the certificate specified must contain the complete certificate chain (certificate bundle).

HTTPSCertFile

Specifies the path of the certificate file to be used for the HTTPS handshake.

HTTPSCertKeyFile

Specifies the path of the certificate key file to be used for the HTTPS handshake.

HTTPSCRLDir

Specifies the path to a directory containing certificate revocation lists (CRLs), which will be consulted when checking the certificate of the remote HTTPS server. The certificate filenames in this directory must be in the OpenSSL hashed format.

HTTPSCRLFile

Specifies the path of the certificate revocation list (CRL) which will be consulted when checking the certificate of the remote HTTPS server.

HTTPSKeyPass

Specifies a password for the certificate key file defined in HTTPSCertKeyFile. This directive is not needed for passwordless private keys.

HTTPSSSLCipher

Sets the permitted SSL cipher list, overriding the default. Use the format described in the ciphers man page.

HTTPSSSLCiphersuites

This optional directive can be used to set the permitted cipher list for TLSv1.3. Use the same format as in the HTTPSSSLCipher directive. Refer to the OpenSSL documentation for a list of valid TLS v1.3 cipher suites. The default value is:

TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256

HTTPSSSLCompression

Accepts a boolean value to determine whether data compression should be enabled. The compression algorithm is based on the zlib compression library. If not specified, it defaults to FALSE (compression will be disabled).

Some Linux packages (for example, Debian) use the OpenSSL library provided by the OS and may not support the zlib compression mechanism. The module will emit a warning on startup if compression support is missing. The generic deb/rpm packages are bundled with a zlib-enabled libssl library.

HTTPSSSLProtocol

This directive can be used to set the allowed SSL/TLS protocol(s). It takes a comma-separated list of values which can be any of the following: SSLv2, SSLv3, TLSv1, TLSv1.1, TLSv1.2 and TLSv1.3. By default, the TLSv1.2 and TLSv1.3 protocols are allowed. Note that the OpenSSL library shipped by Linux distributions may not support SSLv2 and SSLv3, and these will not work even if enabled with this directive.

Optional directives

LocalPort

This optional directive specifies the local port number of the connection. If this is not specified, a random high port number will be used, which is not always ideal in firewalled network environments.

Due to the required TIME-WAIT delay in closing connections, attempts to bind to LocalPort may fail. In such cases, the message Address already in use will be written to nxlog.log. If the situation persists, it could impede network performance.

ProxyAddress

Specifies the IP address of the proxy server in case the module needs to connect to a Raijin Database server through a proxy.

The om_raijin module supports only HTTP proxies, i.e. SOCKS4/SOCKS5 proxies are not supported.

ProxyPort

Specifies the port number required to connect to the proxy server.

Reconnect

This optional directive sets the reconnect interval in seconds. If it is set, the module attempts to reconnect in every defined second. If it is not set, the reconnect interval will start at 1 second and doubles with every attempt. If the duration of the successful connection is greater than the current reconnect interval, then the reconnect interval will be reset to 1 sec.

The Reconnect directive must be used with caution. If it is used on multiple systems, it can send reconnect requests simultaneously to the same destination, potentially overloading the destination system. It may also cause NXLog Agent to use unusually high system resources or cause NXLog Agent to become unresponsive.

SNI

This optional directive specifies the hostname used for Server Name Indication (SNI) in HTTPS mode. If not specified, it defaults to the hostname in the URL directive.

Procedures

The following procedures are exported by om_raijin.

reconnect();

Force a reconnection. This can be used from a Schedule block to periodically reconnect to the server.

The reconnect() procedure must be used with caution. If configured, it can attempt to reconnect after every event sent, potentially overloading the destination system.

Examples

Example 1. Sending unstructured plain text logs

This configuration reads log messages from a file and forwards them to a Raijin Database server deployed on localhost. No further processing is done on the log records.

nxlog.conf

<Extension json>
    Module     xm_json
</Extension>

<Input file>
    Module     im_file
    File       '/var/log/myapp*.log'
</Input>

<Output raijin_local>
    Module     om_raijin
    URL        http://localhost:2500
    DBName     logdb
    DBTable    logs
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded.

Output sample

The following is the JSON-formatted log record that will be sent to the Raijin Database server.

{
  "raw_event": "Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded."
}

Example 2. Sending plain text logs with metadata

This configuration reads log records from a file and adds a $Hostname metadata field. Log records are converted to JSON using the to_json() procedure of the xm_json module before they are forwarded to the Raijin Database server.

nxlog.conf

<Extension json>
    Module     xm_json
</Extension>

<Input file>
    Module     im_file
    File       '/var/log/myapp*.log'
    Exec       $Hostname = hostname();
    Exec       $Message = $raw_event;
</Input>

<Output raijin_local>
    Module     om_raijin
    URL        http://localhost:2500
    DBName     logdb
    DBTable    logs
    Exec       to_json();
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded.

Output sample

The following is the JSON-formatted log record that will be sent to the Raijin Database server.

{
  "EventReceivedTime": "2021-03-24T16:52:20.457348+01:00",
  "SourceModuleName": "file",
  "SourceModuleType": "im_file",
  "Hostname": "pc1",
  "Message": "Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded."
}

Example 3. Sending structured syslog records

This configuration reads syslog records from a file. It uses the parse_syslog() procedure of the xm_syslog module to parse logs into structured data. Log records are then converted to JSON using the to_json() procedure of the xm_json module before they are forwarded to the Raijin Database server.

nxlog.conf

<Extension syslog>
    Module     xm_syslog
</Extension>

<Extension json>
    Module     xm_json
</Extension>

<Input file>
    Module     im_file
    File       '/var/log/myapp*.log'
    Exec       parse_syslog();
</Input>

<Output raijin_local>
    Module     om_raijin
    URL        http://localhost:2500
    DBName     logdb
    DBTable    logs
    Exec       to_json();
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

Mar 24 15:58:53 pc1 systemd[1452]: tracker-store.service: Succeeded.

Output sample

The following is the JSON-formatted log record that will be sent to the Raijin Database server.

{
  "EventReceivedTime": "2021-03-24T16:30:18.920342+01:00",
  "SourceModuleName": "file",
  "SourceModuleType": "im_file",
  "SyslogFacilityValue": 1,
  "SyslogFacility": "USER",
  "SyslogSeverityValue": 5,
  "SyslogSeverity": "NOTICE",
  "SeverityValue": 2,
  "Severity": "INFO",
  "Hostname": "pc1",
  "EventTime": "2021-03-24T15:58:53.000000+01:00",
  "SourceName": "systemd",
  "ProcessID": 1452,
  "Message": "tracker-store.service: Succeeded."
}

Example 4. Sending JSON-formatted logs with metadata

This configuration reads JSON-formatted log records from a file. It uses the parse_json() procedure of the xm_json module to parse logs into structured data and adds an $EventType metadata field. Log records are then converted back to JSON using the to_json() procedure before they are forwarded to the Raijin Database server.

nxlog.conf

<Extension json>
    Module     xm_json
</Extension>

<Input file>
    Module     im_file
    File       '/var/log/myapp*.log'
    Exec       parse_json();
    Exec       $EventType = "browser-history";
</Input>

<Output raijin_local>
    Module     om_raijin
    URL        http://localhost:2500
    DBName     logdb
    DBTable    logs
    Exec       to_json();
</Output>

Input sample

The following is a log record sample read by NXLog Agent.

{
  "AccessTime": "2021-03-24T16:30:43.000000+01:00",
  "URL": "https://nxlog.co",
  "Title": "High Performance Log Collection Solutions",
  "Username": "user1"
}

Output sample

The following is the JSON-formatted log record that will be sent to the Raijin Database server.

{
  "EventReceivedTime": "2021-03-24T17:14:23.908155+01:00",
  "SourceModuleName": "file",
  "SourceModuleType": "im_file",
  "AccessTime": "2021-03-24T16:30:43.000000+01:00",
  "URL": "https://nxlog.co",
  "Title": "High Performance Log Collection Solutions",
  "Username": "user1",
  "EventType": "browser-history"
}

Example 5. Sending logs to a Raijin Database cluster of servers in failover mode

This configuration sends logs to a cluster of Raijin Database servers in failover mode. The cluster is comprised of three hosts: http://raijin-1.example.com:2500, http://localhost:2500, and http://192.168.1.123:2500.

nxlog.conf

<Extension json>
    Module  xm_json
</Extension>

<Output raijin_cluster>
    Module  om_raijin
    URL     http://raijin-1.example.com:2500
    URL     http://localhost:2500
    URL     http://192.168.1.123:2500
    DBName  logdb
    DBTable logs
</Output>