---
schema_version: "1"
id: 24f26a4fa29cb52bb893bf269b2fb1614824da0192082c825ba4a92d316ef067
title: Configure Tracing Module Logging Variable Operations
collection: mulesoft
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locale: en-us
portal_url: https://docs.salesforce.com/mulesoft/current/en-us/tracing-module/latest/tracing-module-logging.md
canonical_url: https://docs.mulesoft.com/tracing-module/latest/tracing-module-logging
source_site: docs.mulesoft.com
content_type: documentation
content_hash: 3000a5bb03441ef384fdb9f585387162cbbd6cd292c611543f892163ab10e27f
description: MuleSoft Documentation Site
release: "1.3"
latest: true
---
---
product: Tracing Module
version: 1.3
is-latest-version: true
---
# Configure Tracing Module Logging Variable Operations
> For the full documentation index, see: https://docs.mulesoft.com/llms.txt
The Tracing module **Clear logging variables**, **Remove logging variable** and **Set logging
variable** operations enable you to enhance your logs by adding, removing, and clearing variables
from the logging context of a single Mule event.
Mapped Diagnostic Context (MDC) enriches logging and improves tracking by providing more context or
information in the logs for the current Mule event. By default, Mule logs two MDC entries:
`processor`, which shows the location of the current event, and `event`, which shows the correlation
ID of the event.
## Before You Begin
To use the Tracing module logging operations, complete the following tasks:
- Add the module to your integration project. See
[Add the Module to Your Integration Project](https://docs.mulesoft.com/tracing-module/latest/tracing-module-config-acb#add-module-to-project).
- Change the pattern layouts in the `log4j.xml` file to `MDC`.
## Change the Pattern Layouts in the log4j.xml File
This change instructs Mule to automatically add the MDC context, which includes the correlation ID
and the processor path. In the Explorer view, open `log4j2.xml` in `src/main/resources` of your
integration project, or `/conf/log4j2.xml` in your Mule instance.
In the editor, replace `[processor: %X{processorPath}; event: %X{correlationId}]` with `[%MDC]`.
### Example log4j.xml File Configurations
Example: Default log4j.xml file without MDC logging.
Example: Updated log4j.xml file with MDC logging.
## Configure Tracing Module Operations in Anypoint Code Builder
To configure the logging variables operations, add any of the available operations **Clear logging
variables**, **Remove logging variable** or **Set logging variables** to your Mule app flow and
specify the corresponding attributes.
In the following example, you configure the **Set logging variables** operation:
1. Click the  (**Add
component**) icon, search for `Tracing`, and select **Set logging variable**.
2. On the **General** tab, set **Variable name** to `testVar` and **Value** to `testValue`.
In the configuration XML file, the `` configuration looks like this:
```xml
...
...
```
After executing the flow, the output logs are:
INFO 2021-04-08 16:58:26,882 \[\[MuleRuntime\].uber.15: \[test-project-app\].exampleFlow.CPU\_LITE
@18f679\] \[{correlationId=c85e16c0-98a4-11eb-bc34-cac765a2219b,
processorPath=exampleFlow/processors/2, testVar=testValue}\]
org.mule.runtime.core.internal.processor.LoggerMessageProcessor: Example
The previous logging context example affects any output of a **Logger** component and any internal
logging that Mule runtime engine produces.
## Create a Set Logging Variable Mule App
In the following example, you configure the **Set logging variable** operation to log variables
based on the request payload and attributes:
1. Click the  (**Add
component**) icon, search for `Listener`, and select **Listener** from the **HTTP** results.
2. On the **General** tab, set **Path** to `/order`.
3. Add an HTTP Listener configuration (``) for the listener. See
[Add a Global Configuration](https://docs.mulesoft.com/tracing-module/latest/tracing-module-config-acb#add-global-config).
4. Click the  (**Add
component**) icon after **Listener**, search for `Tracing`, and select **Set logging variable**.
5. On the **General** tab, set **Variable name** to `customerId` and **Value** to
`#[payload.customerId]` to log the customer ID sent in the request.
6. Click the  (**Add
component**) icon after the first **Set logging variable** operation, search for `Tracing`, and
select **Set logging variable** again.
7. On the **General** tab, set **Variable name** to `requestPath` and **Value** to
`'#["$(attributes.method):$(attributes.requestPath)"]'` to log the request path.
8. Click the  (**Add
component**) icon after the second **Set logging variable** operation, search for `Logger`, and
select it.
9. On the **General** tab, set **Message** to `#[output application/json --- payload]` to log the
request payload.
10. Run your application in debug mode.
11. Send the following curl command:
```xml
curl --location --request GET '0.0.0.0:8081/order' \
--header 'Content-Type: application/json' \
--data-raw '{
"orderId": 548102842,
"customerId": "ARG-12934",
"items": [
"CP-123",
"CP-452"
]
}'
```
The output logs `customerId`, `requestPath`, and the request payload:
```xml
INFO 2021-04-09 11:14:38,409 [[MuleRuntime].uber.05: [tracing-module].tracing-moduleFlow.CPU_LITE @34a62707] [processor: tracing-moduleFlow/processors/2; event: eb2b2461-993d-11eb-8a64-4865ee1fd814] {correlationId=eb2b2461-993d-11eb-8a64-4865ee1fd814, customerId=ARG-12934, processorPath=tracing-moduleFlow/processors/2, requestPath=GET:/order} org.mule.runtime.core.internal.processor.LoggerMessageProcessor: {
"orderId": 548102842,
"customerId": "ARG-12934",
"items": [
"CP-123",
"CP-452"
]
}
```
### XML for the Set Logging Variable Mule App
Paste this code into the configuration XML file of your integration project to quickly load the flow
for this example into your Mule app:
```xml
```
## See Also
- [Tracing Module Examples](https://docs.mulesoft.com/tracing-module/latest/tracing-module-examples)
- [Salesforce Help](https://help.salesforce.com)