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Reference

Components

otelcol

otelcol.receiver.tcplog

Experimental

`otelcol.receiver.tcplog`

EXPERIMENTAL: This is an experimental component. Experimental components are subject to frequent breaking changes, and may be removed with no equivalent replacement. The stability.level flag must be set to experimental to use the component.

otelcol.receiver.tcplog accepts log messages over a TCP connection and forwards them as logs to other otelcol.* components.

Note
otelcol.receiver.tcplog is a wrapper over the upstream OpenTelemetry Collector tcplog receiver. Bug reports or feature requests will be redirected to the upstream repository, if necessary.

You can specify multiple otelcol.receiver.tcplog components by giving them different labels.

Usage

otelcol.receiver.tcplog "<LABEL>" {
  listen_address = "<IP_ADDRESS:PORT>"

  output {
    logs    = [...]
  }
}

Arguments

You can use the following arguments with otelcol.receiver.tcplog:

Name	Type	Description	Default	Required
`listen_address`	`string`	The `<HOST:PORT>` address to listen to for logs messages.		yes
`add_attributes`	`bool`	Add `net.*` attributes to log messages according to OpenTelemetry semantic conventions.	`false`	no
`encoding`	`string`	The encoding of the log messages.	`"utf-8"`	no
`max_log_size`	`string`	The maximum size of a log entry to read before failing.	`"1MiB"`	no
`one_log_per_packet`	`bool`	Skip log tokenization, improving performance when messages always contain one log and multiline isn’t used.	`false`	no

The encoding argument specifies the encoding of the incoming log messages. encoding must be one of utf-8, utf-16le, utf-16be, ascii, big5, or nop. Refer to the upstream receiver documentation for more details.

The max_log_size argument has a minimum value of 64KiB.

Blocks

You can use the following blocks with otelcol.receiver.tcplog:

Block	Description	Required
`output`	Configures where to send received telemetry data.	yes
`debug_metrics`	Configures the metrics that this component generates to monitor its state.	no
`multiline`	Configures rules for multiline parsing of incoming messages	no
`retry_on_failure`	Configures the retry behavior when the receiver encounters an error downstream in the pipeline.	no
`tls`	Configures TLS for the TCP server.	no

`output`

Required

The output block configures a set of components to forward resulting telemetry data to.

The following arguments are supported:

Name	Type	Description	Default	Required
`logs`	`list(otelcol.Consumer)`	List of consumers to send logs to.	`[]`	no

You must specify the output block, but all its arguments are optional. By default, telemetry data is dropped. Configure the logs argument accordingly to send telemetry data to other components, .

`debug_metrics`

The debug_metrics block configures the metrics that this component generates to monitor its state.

The following arguments are supported:

Name	Type	Description	Default	Required
`disable_high_cardinality_metrics`	`boolean`	Whether to disable certain high cardinality metrics.	`true`	no
`level`	`string`	Controls the level of detail for metrics emitted by the wrapped collector.	`"detailed"`	no

disable_high_cardinality_metrics is the Grafana Alloy equivalent to the telemetry.disableHighCardinalityMetrics feature gate in the OpenTelemetry Collector. It removes attributes that could cause high cardinality metrics. For example, attributes with IP addresses and port numbers in metrics about HTTP and gRPC connections are removed.

Note
If configured, disable_high_cardinality_metrics only applies to otelcol.exporter.* and otelcol.receiver.* components.

level is the Alloy equivalent to the telemetry.metrics.level feature gate in the OpenTelemetry Collector. Possible values are "none", "basic", "normal" and "detailed".

`multiline`

The multiline block configures logic for splitting incoming log entries. The following arguments are supported:

Name	Type	Description	Default	Required
`line_end_pattern`	`string`	A regular expression that matches the end of a log entry.		no
`line_start_pattern`	`string`	A regular expression that matches the beginning of a log entry.		no
`omit_pattern`	`bool`	Omit the start/end pattern from the split log entries.	`false`	no

A multiline block must contain either line_start_pattern or line_end_pattern.

If a multiline block isn’t set, log entries won’t be split.

`retry_on_failure`

The retry_on_failure block configures the retry behavior when the receiver encounters an error downstream in the pipeline. A backoff algorithm is used to delay the retry upon subsequent failures. The following arguments are supported:

Name	Type	Description	Default	Required
`enabled`	`bool`	If set to `true` and an error occurs, the receiver will pause reading the log files and resend the current batch of logs.	`false`	no
`initial_interval`	`duration`	The time to wait after first failure to retry.	`1s`	no
`max_elapsed_time`	`duration`	The maximum age of a message before the data is discarded.	`5m`	no
`max_interval`	`duration`	The maximum time to wait after applying backoff logic.	`30s`	no

If max_elapsed_time is set to 0 data is never discarded.

`tls`

The tls block configures TLS settings used for a server. If the tls block isn’t provided, TLS won’t be used for connections to the server.

The following arguments are supported:

Name	Type	Description	Default	Required
`ca_file`	`string`	Path to the CA file.		no
`ca_pem`	`string`	CA PEM-encoded text to validate the server with.		no
`cert_file`	`string`	Path to the TLS certificate.		no
`cert_pem`	`string`	Certificate PEM-encoded text for client authentication.		no
`include_system_ca_certs_pool`	`boolean`	Whether to load the system certificate authorities pool alongside the certificate authority.	`false`	no
`key_file`	`string`	Path to the TLS certificate key.		no
`key_pem`	`secret`	Key PEM-encoded text for client authentication.		no
`max_version`	`string`	Maximum acceptable TLS version for connections.	`"TLS 1.3"`	no
`min_version`	`string`	Minimum acceptable TLS version for connections.	`"TLS 1.2"`	no
`cipher_suites`	`list(string)`	A list of TLS cipher suites that the TLS transport can use.	`[]`	no
`reload_interval`	`duration`	The duration after which the certificate is reloaded.	`"0s"`	no
`client_ca_file`	`string`	Path to the TLS cert to use by the server to verify a client certificate.		no
`curve_preferences`	`list(string)`	Set of elliptic curves to use in a handshake.	`[]`	no

If reload_interval is set to "0s", the certificate never reloaded.

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

ca_pem and ca_file
cert_pem and cert_file
key_pem and key_file

If cipher_suites is left blank, a safe default list is used. Refer to the Go Cipher Suites documentation for a list of supported cipher suites.

client_ca_file sets the ClientCA and ClientAuth to RequireAndVerifyClientCert in the TLSConfig. Refer to the Go TLS documentation for more information.

The curve_preferences argument determines the set of elliptic curves to prefer during a handshake in preference order. If not provided, a default list is used. The set of elliptic curves available are X25519, P521, P256, and P384.

Exported fields

otelcol.receiver.tcplog doesn’t export any fields.

Component health

otelcol.receiver.tcplog is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.receiver.tcplog doesn’t expose any component-specific debug information.

Debug metrics

otelcol.receiver.tcplog doesn’t expose any component-specific debug metrics.

Example

This example receives log messages from TCP and logs them.

otelcol.receiver.tcplog "default" {
    listen_address = "localhost:1515"
    output {
        logs = [otelcol.exporter.debug.default.input]
    }
}

otelcol.exporter.debug "default" {}

Compatible components

otelcol.receiver.tcplog can accept arguments from the following components:

Components that export OpenTelemetry otelcol.Consumer

Note
Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.

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`otelcol.receiver.tcplog`

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