--- schema_version: "1" id: dfff9992de384fee6c0e4e9c05d132bdc05ab221827e9c667fdab547ec1cb7d3 title: Message Logging Policy collection: mulesoft version: current locale: en-us portal_url: https://docs.salesforce.com/mulesoft/current/en-us/gateway/latest/policies-included-message-logging.md canonical_url: https://docs.mulesoft.com/gateway/latest/policies-included-message-logging source_site: docs.mulesoft.com content_type: documentation content_hash: 83744e38442b1a02f1bc08c6f98a1c8ce7444c5683339ccc043a7124d734d4e1 description: MuleSoft Documentation Site release: "1.14" latest: true --- # Message Logging Policy

Policy name

Message Logging

Summary

Logs custom messages using information from incoming requests, responses from the backend, or information from other policies applied to the same API endpoint

Category

Troubleshooting

First Omni Gateway version available

v1.0.0

Release Notes

Message Logging

Returned Status Codes

No return codes exist for this policy
## [](#summary)Summary The Message Logging policy logs custom messages using information from incoming requests, responses from the backend, or information from other policies applied to the same API endpoint.
To use multiple log levels for different configurations, add multiple configurations within a single Message Logging policy.
## [](#prerequisites)Prerequisites You must have the Anypoint Platform Organization Administrators role or have permission to create or manage APIs. ## [](#configuring-policy-parameters)Configuring Policy Parameters ### [](#local-mode)Omni Gateway Local Mode When you apply the policy via declarative configuration files, Refer to the following policy definition and table of parameters: \- policyRef: name: message-logging-flex config: loggingConfiguration: - itemName: // REQUIRED itemData: //REQUIRED message: // REQUIRED conditional: // OPTIONAL category: // OPTIONAL level: // REQUIRED firstSection: // OPTIONAL secondSection: // OPTIONAL enableDataMasking: // OPTIONAL dataMasking: // OPTIONAL entities: - // Supported values: Email, US SSN, Credit Card, Phone Number customPatterns: - name: pattern:
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 Message Logging Severity Levels.

loggingConfiguration.itemData.firstSection

Optional

true

Boolean that indicates if messages are logged before the API endpoint is called, taking into account the order in which this policy is applied.

loggingConfiguration.itemData.secondSection

Optional

false

Boolean that indicates if messages are logged after the API endpoint is called, taking into account the order in which this policy is applied.

enableDataMasking

Optional

false

When enabled, the policy detects and masks configured PII in log messages before they are written. Request and response bodies are forwarded to the upstream service unchanged.

dataMasking.entities

Optional

[]

List of built-in PII types to mask. Supported values: Email, US SSN, Credit Card, and Phone Number.

dataMasking.customPatterns

Optional

[]

List of custom patterns to mask when built-in PII detection doesn’t cover the value. Each pattern must have a name and a pattern (regular expression) property.
#### [](#resource-configuration-example)Resource Configuration Example \- policyRef: name: message-logging-flex config: loggingConfiguration: - itemName: "Config 1" itemData: message: "#\[payload\]" conditional: "#\[attributes.queryParams\['QueryParam'\]=='someValue'\]" level: "ERROR" firstSection: true - itemName: "Config 2" itemData: message: "#\['literal string'\]" level: "WARN" secondSection: true firstSection: true ### [](#connected-mode)Managed Omni Gateway and Omni Gateway Connected Mode When you apply the policy from the UI, the following parameters are displayed: ![A form with text fields and checkboxes to set up new logging configurations](/mulesoft/current/en-us/gateway/latest/_images/apim-message-logging-policy-ui.png)
Parameter Description Required?

Message

A DataWeave expression to use for extracting the message to be logged. 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 Message Logging Severity Levels.

Required

Before Calling API

Set to cause your logging policy to log messages before the API endpoint is called, taking into account the order in which this policy is applied.

Optional

After Calling API

Set to cause your logging policy to log messages after the API endpoint is called, taking into account the order in which this policy is applied.

Optional

Enable data masking

Detect and mask configured PII before writing log messages. Request and response bodies are forwarded to the upstream service unchanged.

Optional

PII Detection

Select built-in PII types to mask: Email, US SSN, Credit Card, and Phone Number.

Optional

Custom Patterns

Add a regular expression pattern to mask a value that built-in PII detection doesn’t cover. Each pattern has a name and a regex.

Optional
#### [](#example-of-message-logging-policy-configured-from-the-ui)Example of Message Logging Policy Configured from the UI To better understand how to use the Message Logging policy, consider a fictional retail clothier named Les Vetments. To successfully run its e-commerce portal, Les Vetments must audit the status code of the requests made on its website. For example, if a customer buys or returns a product, or if the company adds or removes a product from its catalog, the transactions must be logged. The IT manager at Les Vetments applies the Message Logging policy to the company APIs to enable logging and viewing any data or transaction changes without making any modifications to the code. To log the attributes of the incoming and outgoing HTTP message, Les Vetments applies the Message Logging policy to the API with the following UI configurations: - **Message**: #\[attributes\] The attributes in the payload must be logged. - **Conditional**: Blank Because Les Vetments requires all attributes, no expression to filter messages is specified. - **Category**: Blank No prefix is required in the log sentence. - **Level**: Info All types of messages are to be logged. The Info log level also includes Warn, Error, or Debug log messages. - **Before Calling API**: Checked All transactions that occur before the API is called are to be logged. - **After calling API**: Checked All transactions that occur after the API is called are to be logged. Following this configuration, whenever customers access the Les Vetments catalogue or add or remove items from their carts, or when an item is added or removed from the Les Vetments catalog, logs are generated: ```text ********************************************************************** * Policy: message-logging-1351146-proxy * * OS encoding: UTF-8, Mule encoding: UTF-8 * * * ********************************************************************** 21:56:50.147 11/30/2020 Worker-0 [MuleRuntime].uber.06: [message-logging-771181-proxy].771181-message-logging.CPU_LITE @71625864 INFO event:184152a0-3370-11eb-b732-0a8c1820c088 org.mule.extension.http.api.HttpRequestAttributes { Request path=/proxy/1 Raw request path=/proxy/1 Method=GET Listener path=/proxy/* Local Address=/172.25.159.101:8081 Query String= Relative Path=/proxy/1 Masked Request Path=/1 Remote Address=/18.191.37.179:21836 Request Uri=/proxy/1 Raw request Uri=/proxy/1 Scheme=http Version=HTTP/1.1 Headers=[ host=logging-policy.us-e2.cloudhub.io x-real-ip=204.14.236.154 accept=*/* user-agent=curl/7.54.0 x-forwarded-for=204.14.236.154 x-forwarded-port=80 x-forwarded-proto=http x-sigsci-agentresponse=200 x-sigsci-mac=7caf3820a5c07d06ef827f1565678167 ] Query Parameters=[] URI Parameters=[] } 21:56:50.254 11/30/2020 Worker-0 [MuleRuntime].uber.07: [logging-policy].proxy.CPU_LITE @f0ce617 INFO event:184152a0-3370-11eb-b732-0a8c1820c088 org.mule.extension.http.api.HttpResponseAttributes { Status Code=200 Reason Phrase=OK Headers=[ date=Tue, 01 Dec 2020 00:56:50 GMT content-type=application/json; charset=utf-8 set-cookie=__cfduid=d8afa23a4627ebef39cbc54fea223cb231606784210; expires=Thu, 31-Dec-20 00:56:50 GMT; path=/; domain=.typicode.com; HttpOnly; SameSite=Lax x-powered-by=Express x-ratelimit-limit=1000 x-ratelimit-remaining=999 x-ratelimit-reset=1606784265 vary=Origin, Accept-Encoding access-control-allow-credentials=true cache-control=max-age=43200 pragma=no-cache expires=-1 x-content-type-options=nosniff etag=W/"53-hfEnumeNh6YirfjyjaujcOPPT+s" via=1.1 vegur cf-cache-status=MISS accept-ranges=bytes cf-request-id=06bd666d0a0000386b7a1fc000000001 expect-ct=max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct" report-to={"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report?s=qUAIXoQ7qqqvFzjcwGrmK2r2PcSfDZ75jFJd0Gi0BLBUMHAcnC9wJ9I%2FEHJtk%2Bra%2FXWqkA%2F5%2FlzoWoC6YS2Lew%2BqKgjhaphHqx5WrZ0CKHMalhcM9it%2Fks0qzQGwbsRzQg%3D%3D"}],"group":"cf-nel","max_age":604800} nel={"report_to":"cf-nel","max_age":604800} cf-ray=5fa8d9c1a8c6386b-IAD ] } 12:18:31.770 11/18/2020 Worker-0 agw-policy-set-deployment.01 INFO Applied policy message-logging-1351146 version 1.0.0 to API testLoggingNew-v1-v1:16481163 (16481163) in application messagelog ``` To log headers, Les Vetments uses the following code snippet in the **Message** field: `#[attributes.headers]` To customize the log messages based on the event and the action performed, Les Vetments uses the following code snippet in the **Message** field: `#['User ' authentication.clientId ' performed action ' attributes.method ' on ' attributes.requestPath ' with Payload: ' ++ payload]` ## [](#dataweave-support)DataWeave Expressions Support The Message Logging policy supports the [standard DataWeave Expressions supported by Omni Gateway policies](https://docs.mulesoft.com/gateway/latest/policies-dataweave-support) and the following additional [`vars`](https://docs.mulesoft.com/dataweave/latest/dataweave-variables-context) DataWeave expressions. Format the following expressions `[vars.]`, for example `[vars.orgId]`: - `orgId` - `masterOrgId` - `envId` - `apiId` - `apiName` - `apiInstanceName` - `apiVersion` - `receivedTs` (rfc3339) - `repliedTs` (rfc3339, only available in request context) - `runtimeVersion` (For example: `v1.7.0`) - `hostId` (For example: `my-host`) - `reqId` (Referred to as `traceId` in Omni Gateway logs) - `requestDisposition` (`PROCESSED` or `VIOLATION`, only available in request context) - `request.remoteAddress` - `request.method` - `request.requestPath` - `request.headers` (all request headers) - `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)How This Policy Works Logging a policy consists of the following sequence: 1. A request is sent to the API. 2. The message is logged if the following 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 was not set, or was set and the condition was met. 3. The API response is returned. Message Logging Policy does not interfere with the execution of any policy nor its flow. 4. The message appears in the application log. ## [](#about-the-logging-format)About the Logging Format A message log uses the following format: ` [flex-gateway-envoy][] wasm log .default..default.svc main: [req: ] [accessLog] ` - `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. ## [](#logging-states-during-events)Logging States During Events Message logging occurs at specific intervals during a request flow: - Before logging an API flow: ![State before logging an API flow](/mulesoft/current/en-us/gateway/latest/_images/apim-message-logging-policy-states-1.png) - After logging an API flow: ![State after logging an API flow](/mulesoft/current/en-us/gateway/latest/_images/apim-message-logging-policy-states-2.png) - Error handler after API flow: ![State after the error handler executes](/mulesoft/current/en-us/gateway/latest/_images/apim-message-logging-policy-states-3.png) ## [](#severity-levels)Message Logging Severity Levels When you configure a Message Logging policy for your API instance, you can assign a severity level. Each severity level includes a specific set of information in the log report. Log reports include the severity level you select and the following levels on the hierarchy. For example, if you select DEBUG, the log reports include the DEBUG severity level as well as the INFO, WARN, and ERROR severity levels. However, if you select ERROR, the log reports include only error messages. The following table describes the type of information included in the logs for each severity level:
Log Severity Level Description

DEBUG

Tracing information used by application developers.

INFO

Informational messages that highlight the progress of the application.

WARN

Potentially harmful situations that indicate potential problems.

ERROR

Events that prevent normal program execution but might allow the application to continue running.