Is it possible to intercept all the flows with Mule 4? Looks like MuleSoft has removed custom-interceptor, AbstractEnvelopeInterceptor, etc. from Mule 4.
I wanted to add some audit loggers like "Entering XYZ flow" and "Exiting XYZ flow". Instead of adding these loggers in each and every flow, I was thinking if this can be done with some common code.
Interceptors are deprecated in Mule 4. See the documentation on migrating core components for details. You can use custom policies instead.
In Mule 4, to log a variable, the following approach can be taken:
<logger level="INFO" doc:name="My Var" message="#[vars.myVar]" category="values"/>
The expression inside #[ ] is an expression uses the DataWeave Expression Language.
To create more complex expressions to log variables, the function write() can be used:
<logger level="INFO" doc:name="My Var" message="#[' myVar = $(write(vars.myVar))']" category="values"/>
This will provide logging output as demonstrated:
org.mule.runtime.core.internal.processor.LoggerMessageProcessor: myVar = "the value" as String {class: "java.lang.String";, encoding: "UTF-8", mimeType: "application/java", raw: "the value" as String {class: "java.lang.String";}}
Note the following: The write function prints the variable myVar and its metadata (encoding, mime type, ray vaule, Java class)
The expression inside the #[ ] is a String. When we want to evaluate an expression inside a String we use $( ). For example this String: '$(1 + 1)' evaluates to '2'
