nixos-config/nixos/system/server/graylog-exporter.nix

{ lib, ... }: {

  # send data to graylog
  services.SystemdJournal2Gelf.enable = lib.mkDefault false;
  services.SystemdJournal2Gelf.graylogServer = "workhorse.private:11201";

  services.journalbeat = {
    enable = true;
    # https://docs.graylog.org/en/4.0/pages/sending/journald.html
    extraConfig = ''
      journalbeat.inputs:
        # Paths that should be crawled and fetched. Possible values files and directories.
        # When setting a directory, all journals under it are merged.
        # When empty starts to read from local journal.
      - paths: []

        # The number of seconds to wait before trying to read again from journals.
        #backoff: 1s
        # The maximum number of seconds to wait before attempting to read again from journals.
        #max_backoff: 20s

        # Position to start reading from journal. Valid values: head, tail, cursor
        seek: tail

        # Fallback position if no cursor data is available.
        #cursor_seek_fallback: tail

        # Exact matching for field values of events.
        # Matching for nginx entries: "systemd.unit=nginx"
        #include_matches: []

      output.logstash:
        # Boolean flag to enable or disable the output module.
        enabled: true

        # Graylog host and the beats input
        hosts: ["workhorse.private:5044"]

        # Number of workers per Graylog host.
        #worker: 1

        # Set gzip compression level.
        #compression_level: 3

        # Configure escaping HTML symbols in strings.
        #escape_html: false

        # Optional maximum time to live for a connection to Graylog, after which the
        # connection will be re-established.  A value of `0s` (the default) will
        # disable this feature.
        #
        # Not yet supported for async connections (i.e. with the "pipelining" option set)
        ttl: 30s

        # Optionally load-balance events between Graylog hosts. Default is false.
        #loadbalance: false

        # If enabled only a subset of events in a batch of events is transferred per
        # transaction.  The number of events to be sent increases up to `bulk_max_size`
        # if no error is encountered.
        slow_start: true

        # The number of seconds to wait before trying to reconnect to Graylog
        # after a network error. After waiting backoff.init seconds, the Beat
        # tries to reconnect. If the attempt fails, the backoff timer is increased
        # exponentially up to backoff.max. After a successful connection, the backoff
        # timer is reset. The default is 1s.
        backoff.init: 1s

        # The maximum number of seconds to wait before attempting to connect to
        # Graylog after a network error. The default is 60s.
        backoff.max: 60s

        # SOCKS5 proxy server URL
        #proxy_url: socks5://user:password@socks5-server:2233

        # Resolve names locally when using a proxy server. Defaults to false.
        #proxy_use_local_resolver: false

        # Enable SSL support. SSL is automatically enabled if any SSL setting is set.
        #ssl.enabled: true

        # Configure SSL verification mode. If `none` is configured, all server hosts
        # and certificates will be accepted. In this mode, SSL based connections are
        # susceptible to man-in-the-middle attacks. Use only for testing. Default is
        # `full`.
        #ssl.verification_mode: full

        # List of supported/valid TLS versions. By default all TLS versions from 1.1
        # up to 1.3 are enabled.
        #ssl.supported_protocols: [TLSv1.1, TLSv1.2, TLSv1.3]

        # Optional SSL configuration options. SSL is off by default.
        # List of root certificates for HTTPS server verifications
        #ssl.certificate_authorities: ["/etc/pki/root/ca.pem"]

        # Certificate for SSL client authentication
        #ssl.certificate: "/etc/pki/client/cert.pem"

        # Client certificate key
        #ssl.key: "/etc/pki/client/cert.key"

        # Optional passphrase for decrypting the Certificate Key.
        #ssl.key_passphrase: 

        # Configure cipher suites to be used for SSL connections
        #ssl.cipher_suites: []

        # Configure curve types for ECDHE-based cipher suites
        #ssl.curve_types: []

        # Configure what types of renegotiation are supported. Valid options are
        # never, once, and freely. Default is never.
        #ssl.renegotiation: never

        # Configure a pin that can be used to do extra validation of the verified certificate chain,
        # this allow you to ensure that a specific certificate is used to validate the chain of trust.
        #
        # The pin is a base64 encoded string of the SHA-256 fingerprint.
        #ssl.ca_sha256: ""

        # The number of times to retry publishing an event after a publishing failure.
        # After the specified number of retries, the events are typically dropped.
        # Some Beats, such as Filebeat and Winlogbeat, ignore the max_retries setting
        # and retry until all events are published.  Set max_retries to a value less
        # than 0 to retry until all events are published. The default is 3.
        #max_retries: 3

        # The maximum number of events to bulk in a single Graylog request. The
        # default is 2048.
        bulk_max_size: 2048

        # The number of seconds to wait for responses from the Graylog server before
        # timing out. The default is 30s.
        #timeout: 30s
    '';
  };

}