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Outbound Message Logging Policy

Policy name

Outbound Message Logging

Summary

Logs custom messages from outbound requests sent to upstream services, responses from upstream services, or information from other outbound policies applied to the same upstream service

Category

Troubleshooting

First Flex Gateway version available

v1.11.0

Returned Status Codes

No return codes exist for this policy

Summary

The Outbound Message Logging policy logs custom messages from outbound requests sent to upstream services, responses from upstream services, or information from other outbound policies applied to the same upstream service. This policy is applied at the upstream level.

Configuring Policy Parameters

Flex Gateway Local Mode

In Local Mode, you apply the policy to your API via declarative configuration files. Refer to the following policy definition and table of parameters:

apiVersion: gateway.mulesoft.com/v1beta1
kind: PolicyBinding
metadata:
  name: outbound-message-logging
spec:
  targetRef:
    kind: Service
    name: upstream
  policyRef:
    name: message-logging-outbound-flex
  config:
    loggingConfiguration: <array>
      - itemName: <string> // REQUIRED
        itemData: //REQUIRED
          message: <dataweave> // REQUIRED
          conditional: <dataweave> // OPTIONAL
          category: <string> // OPTIONAL
          level: <string> // REQUIRED
          firstSection: <bool> // OPTIONAL
          secondSection: <bool> // OPTIONAL
Parameter Required or Optional Default Value Description

loggingConfiguration

Required

N/A

Array of configurations.

loggingConfiguration.itemName

Required

N/A

Configuration name.

loggingConfiguration.itemData.message

Required

N/A

DataWeave expression that resolves to the message log. To learn more about supported DataWeave expressions, see DataWeave Expressions Support.

loggingConfiguration.itemData.conditional

Optional

true

DataWeave expression that resolves to whether the message should be logged. To learn more about supported DataWeave expressions, see DataWeave Expressions Support.

loggingConfiguration.itemData.category

Optional

Default category

Log message prefix that indicates the package and class where the log is executed.

loggingConfiguration.itemData.level

Required

N/A

Defines the level of message to log: INFO, WARN, ERROR, or DEBUG
For more information, see [severity-levels].

loggingConfiguration.itemData.firstSection

Optional

false

Boolean that indicates if messages are logged before the outbound request is sent to the upstream service, taking into account the order in which this policy is applied.

loggingConfiguration.itemData.secondSection

Optional

false

Boolean that indicates if messages are logged after receiving the response from the upstream service, taking into account the order in which this policy is applied.

Resource Configuration Example

apiVersion: gateway.mulesoft.com/v1beta1
kind: PolicyBinding
metadata:
  name: outbound-message-logging
spec:
  targetRef:
    kind: Service
    name: my-upstream
  policyRef:
    name: message-logging-outbound-flex
  config:
    loggingConfiguration:
      - itemName: "Outbound Request Log"
        itemData:
          message: "#[payload]"
          conditional: "#[attributes.queryParams['debug']=='true']"
          level: "INFO"
          firstSection: true
      - itemName: "Outbound Response Log"
        itemData:
          message: "#['Upstream response: ' ++ attributes.statusCode as String]"
          level: "INFO"
          secondSection: true

Managed Flex Gateway and Flex Gateway Connected Mode

When you apply the policy to your API instance from the UI, the following parameters are displayed:

Parameter Description Required or Optional

Message

A DataWeave expression for extracting the message to be logged from outbound requests or upstream responses. To learn more about supported DataWeave expressions, see DataWeave Expressions Support.

Required

Conditional

A DataWeave Boolean expression used to specify whether a message is to be logged. To learn more about supported DataWeave expressions, see DataWeave Expressions Support.

Optional

Category

A prefix in the log message that indicates the package and class where the log is executed.

Optional

Level

The level of message to log: INFO, WARN, ERROR, or DEBUG.
For more information, see [severity-levels].

Required

Before Sending Request

Set to cause your logging policy to log messages before the outbound request is sent to the upstream service, taking into account the order in which this policy is applied.

Optional

After Receiving Response

Set to cause your logging policy to log messages after receiving the response from the upstream service, taking into account the order in which this policy is applied.

Optional

DataWeave Expressions Support

The Outbound Message Logging policy supports the standard DataWeave Expressions supported by Flex Gateway policies and the following additional vars DataWeave expressions. Format the following expressions [vars.<expressions>], for example [vars.orgId]:

  • orgId

  • masterOrgId

  • envId

  • apiId

  • apiName

  • apiInstanceName

  • apiVersion

  • receivedTs (rfc3339)

  • repliedTs (rfc3339, only available in response context)

  • runtimeVersion (For example: v1.7.0)

  • hostId (For example: my-host)

  • reqId (Referred to as traceId in Flex Gateway logs)

  • requestDisposition (PROCESSED or VIOLATION, only available in request context)

  • request.remoteAddress

  • request.method

  • request.requestPath

  • request.headers (all request headers)

  • upstream.uri (URI of the upstream service)

  • upstream.headers (headers sent to upstream service)

  • upstream.statusCode (status code from upstream response, only available in response context)

  • violation.clientId (Only available in response context)

  • violation.clientName (Only available in response context)

  • violation.policyName (Only available in response context)

  • violation.violationType (VIOLATION or ERROR, only available in response context)

How This Policy Works

Logging an outbound policy consists of the following sequence:

  1. An outbound request is prepared to be sent to an upstream service.

  2. The message is logged if these conditions are true:

    • The level and category of the log defined in the policy are included in the logger defined in the configuration file.

    • Either the conditional field of the policy is not set, or is set and the condition is met.

    • The firstSection flag is enabled (if logging before sending the request).

  3. The request is sent to the upstream service.

  4. The upstream service responds.

  5. The message is logged if these conditions are true:

    • The level and category of the log defined in the policy are included in the logger defined in the configuration file.

    • Either the conditional field of the policy is not set, or is set and the condition is met.

    • The secondSection flag is enabled (if logging after receiving the response).

  6. The response is returned to the client. Outbound Message Logging Policy does not interfere with the execution of any policy nor its flow.

  7. The message appears in the application log.

Logging Format

A message log uses this format:

<date> [flex-gateway-envoy][<level>] wasm log <policy-name>.default.<api-name>.default.svc main: [req: <request uuid>] [accessLog] <message>

  • policy-name: displays the name of the policy binding.

  • api-name: displays the name of the api instance.

  • request uuid: displays a unique identifier for the request that triggered the message.