Documentation Grafana Cloud Instrument and send data Grafana Alloy Reference Components otelcol otelcol.processor.attributes

otelcol.processor.attributes

otelcol.processor.attributes accepts telemetry data from other otelcol components and modifies attributes of a span, log, or metric. It also supports the ability to filter and match input data to determine if it should be included or excluded for attribute modifications.

You can specify multiple otelcol.processor.attributes components by giving them different labels.

Usage

alloy Copy

otelcol.processor.attributes "LABEL" {
  output {
    metrics = [...]
    logs    = [...]
    traces  = [...]
  }
}

Arguments

otelcol.processor.attributes doesn’t support any arguments and is configured fully through inner blocks.

Blocks

The following blocks are supported inside the definition of otelcol.processor.attributes:

The > symbol indicates deeper levels of nesting. For example, include > attribute refers to an attribute block defined inside an include block.

If both an include block and an excludeblock are specified, the include properties are checked before the exclude properties.

action block

The action block configures how to modify the span, log, or metric.

The following attributes are supported:

The value data type must be either a number, string, or boolean.

The supported values for action are:

• insert: Inserts a new attribute in input data where the key does not already exist.

  • The key attribute is required. It specifies the attribute to act upon.
  • One of the value, from_attribute or from_context attributes is required.

• update: Updates an attribute in input data where the key does exist.

  • The keyattribute is required. It specifies the attribute to act upon.
  • One of the value, from_attribute or from_context attributes is required.

• upsert: Either inserts a new attribute in input data where the key does not already exist or updates an attribute in input data where the key does exist.

  • The keyattribute is required. It specifies the attribute to act upon.
  • One of the value, from_attribute or from_contextattributes is required:
    • value specifies the value to populate for the key.
    • from_attribute specifies the attribute from the input data to use to populate the value. If the attribute doesn’t exist, no action is performed.
    • from_context specifies the context value used to populate the attribute value. If the key is prefixed with metadata., the values are searched in the receiver’s transport protocol for additional information like gRPC Metadata or HTTP Headers. If the key is prefixed with auth., the values are searched in the authentication information set by the server authenticator. Refer to the server authenticator’s documentation part of your pipeline for more information about which attributes are available. If the key is client.address, the value will be set to the client address. If the key doesn’t exist, no action is performed. If the key has multiple values the values will be joined with a ; separator.

• hash: Hashes (SHA1) an existing attribute value.

  • The key attribute and/or the pattern attributes is required.

• extract: Extracts values using a regular expression rule from the input key to target keys specified in the rule. If a target key already exists, it will be overridden. Note: It behaves similarly to the Span Processor to_attributes setting with the existing attribute as the source.

  • The key attribute is required. It specifies the attribute to extract values from. The value of key is NOT altered.
  • The pattern attribute is required. It is the regex pattern used to extract attributes from the value of key. The submatchers must be named. If attributes already exist, they will be overwritten.

• convert: Converts an existing attribute to a specified type.

  • The key attribute is required. It specifies the attribute to act upon.
  • The converted_type attribute is required and must be one of int, double or string.

• delete: Deletes an attribute from the input data.

  • The key attribute and/or the pattern attribute is required. It specifies the attribute to act upon.

include block

The include block provides an option to include data being fed into the action blocks based on the properties of a span, log, or metric records.

The following arguments are supported:

match_type is required and must be set to either "regexp" or "strict".

A match occurs if at least one item in the lists matches.

One of the following is also required:

• For spans, one of services, span_names, span_kinds, attribute, resource, or library must be specified with a non-empty value for a valid configuration. The log_bodies, log_severity_texts, log_severity, and metric_names attributes are invalid.
• For logs, one of log_bodies, log_severity_texts, log_severity, attribute, resource, or library must be specified with a non-empty value for a valid configuration. The span_names, span_kinds, metric_names, and services attributes are invalid.
• For metrics, metric_names must be specified with a valid non-empty value for a valid configuration. The span_names, span_kinds, log_bodies, log_severity_texts, log_severity, services, attribute, resource, and library attributes are invalid.

If the configuration includes filters which are specific to a particular signal type, it is best to include only that signal type in the component’s output. For example, adding a span_names filter could cause the component to error if logs are configured in the component’s outputs.

exclude block

The exclude block provides an option to exclude data from being fed into the action blocks based on the properties of a span, log, or metric records.

The following arguments are supported:

match_type is required and must be set to either "regexp" or "strict".

A match occurs if at least one item in the lists matches.

One of the following is also required:

• For spans, one of services, span_names, span_kinds, attribute, resource, or library must be specified with a non-empty value for a valid configuration. The log_bodies, log_severity_texts, log_severity, and metric_names attributes are invalid.
• For logs, one of log_bodies, log_severity_texts, log_severity, attribute, resource, or library must be specified with a non-empty value for a valid configuration. The span_names, span_kinds, metric_names, and services attributes are invalid.
• For metrics, metric_names must be specified with a valid non-empty value for a valid configuration. The span_names, span_kinds, log_bodies, log_severity_texts, log_severity, services, attribute, resource, and library attributes are invalid.

If the configuration includes filters which are specific to a particular signal type, it is best to include only that signal type in the component’s output. For example, adding a span_names filter could cause the component to error if logs are configured in the component’s outputs.

regexp block

This block is an optional configuration for the match_type of "regexp". It configures a Least Recently Used (LRU) cache.

The following arguments are supported:

Enabling cache_enabled could make subsequent matches faster. Cache size is unlimited unless cache_max_num_entries is also specified.

cache_max_num_entries is ignored if cache_enabled is false.

attribute block

This block specifies an attribute to match against:

• More than one attribute block can be defined.
• Only match_type = "strict" is allowed if attribute is specified.
• All attribute blocks must match exactly for a match to occur.

The following arguments are supported:

If value isn’t set, any value will match. The type of value could be a number, a string, or a boolean.

resource block

This block specifies items to match the resources against:

• More than one resource block can be defined.
• A match occurs if the input data resources match at least one resource block.

The following arguments are supported:

If value is not set, any value will match. The type of value could be a number, a string, or a boolean.

library block

This block specifies properties to match the implementation library against:

• More than one library block can be defined.
• A match occurs if the span’s implementation library matches at least one library block.

The following arguments are supported:

If version is unset, any version matches. If version is set to an empty string, it only matches a library version, which is also an empty string.

log_severity block

This block defines how to match based on a log record’s SeverityNumber field.

The following arguments are supported:

If match_undefined is true, entries with undefined severity will match.

The following table lists the severities supported by OTel. The value for min should be one of the values in the “Log Severity” column.

For example, if the min attribute in the log_severity block is “INFO”, then INFO, WARN, ERROR, and FATAL logs will match.

output block

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

The following arguments are supported:

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

debug_metrics block

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

The following arguments are supported:

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.

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

Exported fields

The following fields are exported and can be referenced by other components:

input accepts otelcol.Consumer data for any telemetry signal (metrics, logs, or traces).

Component health

otelcol.processor.attributes is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.processor.attributes does not expose any component-specific debug information.

Examples

Various uses of the “action” block

alloy Copy

otelcol.receiver.otlp "default" {
  http {}
  grpc {}

  output {
    metrics = [otelcol.processor.attributes.default.input]
    logs    = [otelcol.processor.attributes.default.input]
    traces  = [otelcol.processor.attributes.default.input]
  }
}

otelcol.processor.attributes "default" {
    // Inserts a new attribute "attribute1" to spans where
    // the key "attribute1" doesn't exist.
    // The type of `attribute1` is inferred by the configuration.
    // `123` is an integer and is stored as an integer in the attributes.
    action {
        key = "attribute1"
        value = 123
        action = "insert"
    }

    // Inserts a new attribute with a key of "string key" and
    // a string value of "anotherkey".
    action {
        key = "string key"
        value = "anotherkey"
        action = "insert"
    }

    // Setting an attribute on all spans.
    // Any spans that already had `region` now have value `planet-earth`.
    // This can be done to set properties for all traces without
    // requiring an instrumentation change.
    action {
        key = "region"
        value = "planet-earth"
        action = "upsert"
    }

    // The following demonstrates copying a value to a new key.
    // If a span doesn't contain `user_key`, no new attribute `new_user_key` is created.
    action {
        key = "new_user_key"
        from_attribute = "user_key"
        action = "upsert"
    }

    // Hashing existing attribute values.
    action {
        key = "user.email"
        action = "hash"
    }

    // Uses the value from key `example_user_key` to upsert attributes
    // to the target keys specified in the `pattern`.
    // (Insert attributes for target keys that do not exist and update keys that exist.)
    // Given example_user_key = /api/v1/document/12345678/update/v1
    // then the following attributes will be inserted:
    // new_example_user_key: 12345678
    // version: v1
    //
    // Note: Similar to the Span Processor, if a target key already exists,
    // it will be updated.
    //
    // Note: The regex pattern is enclosed in backticks instead of quotation marks.
    // This constitutes a raw Alloy syntax string, and lets us avoid the need to escape backslash characters.
    action {
        key = "example_user_key"
        pattern = `\/api\/v1\/document\/(?P<new_user_key>.*)\/update\/(?P<version>.*)$`
        action = "extract"
    }

    // Converting the type of an existing attribute value.
    action {
        key = "http.status_code"
        converted_type = "int"
        action = "convert"
    }

    // Deleting keys from an attribute.
    action {
        key = "credit_card"
        action = "delete"
    }

    output {
        metrics = [otelcol.exporter.otlp.default.input]
        logs    = [otelcol.exporter.otlp.default.input]
        traces  = [otelcol.exporter.otlp.default.input]
    }
}

otelcol.exporter.otlp "default" {
  client {
    endpoint = sys.env("OTLP_ENDPOINT")
  }
}

Excluding spans based on attributes

For example, the following spans match the properties and won’t be processed by the processor:

• Span1 Name: “svcB”, Attributes: {env: “dev”, test_request: 123, credit_card: 1234}
• Span2 Name: “svcA”, Attributes: {env: “dev”, test_request: false}

The following spans do not match the properties and the processor actions are applied to it:

• Span3 Name: “svcB”, Attributes: {env: 1, test_request: “dev”, credit_card: 1234}
• Span4 Name: “svcC”, Attributes: {env: “dev”, test_request: false}

Note that due to the presence of the services attribute, this configuration works only for trace signals. This is why only traces are configured in the output block.

alloy Copy

otelcol.processor.attributes "default" {
    exclude {
        match_type = "strict"
        services = ["svcA", "svcB"]
        attribute {
            key = "env"
            value = "dev"
        }
        attribute {
            key = "test_request"
        }
    }
    action {
        key = "credit_card"
        action = "delete"
    }
    action {
        key = "duplicate_key"
        action = "delete"
    }
    output {
        traces  = [otelcol.exporter.otlp.default.input]
    }
}

Excluding spans based on resources

A “strict” match_type means that we must strictly match the resource key/value pairs.

Note that the resource attribute is not used for metrics, which is why metrics are not configured in the component output.

alloy Copy

otelcol.processor.attributes "default" {
    exclude {
        match_type = "strict"
        resource {
            key = "host.type"
            value = "n1-standard-1"
        }
    }
    action {
        key = "credit_card"
        action = "delete"
    }
    action {
        key = "duplicate_key"
        action = "delete"
    }
    output {
        logs    = [otelcol.exporter.otlp.default.input]
        traces  = [otelcol.exporter.otlp.default.input]
    }
}

Excluding spans based on a specific library version

A “strict” match_type means that we must strictly match the library key/value pairs.

Note that the library attribute is not used for metrics, which is why metrics are not configured in the component output.

alloy Copy

otelcol.processor.attributes "default" {
    exclude {
        match_type = "strict"
        library {
            name = "mongo-java-driver"
            version = "3.8.0"
        }
    }
    action {
        key = "credit_card"
        action = "delete"
    }
    action {
        key = "duplicate_key"
        action = "delete"
    }
    output {
        logs    = [otelcol.exporter.otlp.default.input]
        traces  = [otelcol.exporter.otlp.default.input]
    }
}

Including and excluding spans based on regex and services

This processor will remove the “token” attribute and will obfuscate the “password” attribute in spans where the service name matches "auth.*" and where the span name does not match "login.*".

Note that due to the presence of the services and span_names attributes, this configuration works only for trace signals. This is why only traces are configured in the output block.

alloy Copy

otelcol.processor.attributes "default" {
    // Specifies the span properties that must exist for the processor to be applied.
    include {
        // "match_type" defines that "services" is an array of regexp-es.
        match_type = "regexp"
        // The span service name must match "auth.*" pattern.
        services = ["auth.*"]
    }

    exclude {
        // "match_type" defines that "span_names" is an array of regexp-es.
        match_type = "regexp"
        // The span name must not match "login.*" pattern.
        span_names = ["login.*"]
    }

    action {
        key = "password"
        action = "update"
        value = "obfuscated"
    }

    action {
        key = "token"
        action = "delete"
    }

    output {
        traces  = [otelcol.exporter.otlp.default.input]
    }
}

Including spans based on regex and attributes

The following demonstrates how to process spans with attributes that match a regexp pattern. This processor will obfuscate the “db.statement” attribute in spans where the “db.statement” attribute matches a regex pattern.

alloy Copy

otelcol.processor.attributes "default" {
    include {
        // "match_type" of "regexp" defines that the "value" attributes 
        // in the "attribute" blocks are regexp-es.
        match_type = "regexp"

        // This attribute ('db.statement') must exist in the span and match 
        // the regex ('SELECT \* FROM USERS.*') for a match.
        attribute {
            key = "db.statement"
            value = "SELECT \* FROM USERS.*"
        }
    }

    action {
        key = "db.statement"
        action = "update"
        value = "SELECT * FROM USERS [obfuscated]"
    }

    output {
        metrics = [otelcol.exporter.otlp.default.input]
        logs    = [otelcol.exporter.otlp.default.input]
        traces  = [otelcol.exporter.otlp.default.input]
    }
}

Including spans based on regex of log body

This processor will remove the “token” attribute and will obfuscate the “password” attribute in spans where the log body matches “AUTH.*”.

Note that due to the presence of the log_bodies attribute, this configuration works only for log signals. This is why only logs are configured in the output block.

alloy Copy

otelcol.processor.attributes "default" {
    include {
        match_type = "regexp"
        log_bodies = ["AUTH.*"]
    }
    action {
        key = "password"
        action = "update"
        value = "obfuscated"
    }
    action {
        key = "token"
        action = "delete"
    }

    output {
        logs    = [otelcol.exporter.otlp.default.input]
    }
}

Including spans based on regex of log severity

The following demonstrates how to process logs that have a severity level which is equal to or higher than the level specified in the log_severity block. This processor will remove the “token” attribute and will obfuscate the “password” attribute in logs where the severity is at least “INFO”.

Note that due to the presence of the log_severity attribute, this configuration works only for log signals. This is why only logs are configured in the output block.

alloy Copy

otelcol.processor.attributes "default" {
    include {
        match_type = "regexp"
		log_severity {
			min = "INFO"
			match_undefined = true
		}
    }
    action {
        key = "password"
        action = "update"
        value = "obfuscated"
    }
    action {
        key = "token"
        action = "delete"
    }

    output {
        logs    = [otelcol.exporter.otlp.default.input]
    }
}

Including spans based on regex of log severity text

The following demonstrates how to process logs that have a severity text that match regexp patterns. This processor will remove the “token” attribute and will obfuscate the “password” attribute in logs where severity matches “info”.

Note that due to the presence of the log_severity_texts attribute, this configuration works only for log signals. This is why only logs are configured in the output block.

alloy Copy

otelcol.processor.attributes "default" {
    include {
        match_type = "regexp"
        log_severity_texts = ["info.*"]
    }
    action {
        key = "password"
        action = "update"
        value = "obfuscated"
    }
    action {
        key = "token"
        action = "delete"
    }

    output {
        logs    = [otelcol.exporter.otlp.default.input]
    }
}

Including metrics based on metric names

The following demonstrates how to process metrics that have a name starting with “counter”. This processor will add a label called “important_label” with a value of “label_val” to the metric. If the label already exists, its value will be updated.

Note that due to the presence of the metric_names attribute, this configuration works only for metric signals. This is why only metrics are configured in the output block.

alloy Copy

otelcol.processor.attributes "default" {
	include {
		match_type = "regexp"
		metric_names = ["counter.*"]
	}
	action {
		key = "important_label"
		action = "upsert"
		value = "label_val"
	}

    output {
        metrics = [otelcol.exporter.otlp.default.input]
    }
}

Compatible components

otelcol.processor.attributes can accept arguments from the following components:

• Components that export OpenTelemetry otelcol.Consumer

otelcol.processor.attributes has exports that can be consumed by the following components:

• Components that consume OpenTelemetry otelcol.Consumer