XForms logging

Enabling XForms logging

Sometimes, an error message or stack trace in the Orbeon Forms log file provides enough information to a developer to figure out what went wrong, but not always. In such cases, you can turn to the XForms engine logging facility. To enable it, make sure you uncomment the following logging <Logger> (Log4j 2.x) or <Category> (Log4j 1.x):

Log4j 2.x (WEB-INF/resources/config/log4j2.xml):

<Logger name="org.orbeon.oxf.xforms.processor.XFormsServer" level="debug"/>

Log4j 1.x (WEB-INF/resources/config/log4j.xml):

<category name="org.orbeon.oxf.xforms.processor.XFormsServer">
    <priority value="debug"/>
</category>

Note: You must restart your Servlet container for those changes to be taken into account.

Fine-grained configuration

Two properties in WEB-INF/resources/config/properties-local.xml control exactly what is logged by the XForms engine:

    <property as="xs:NMTOKENS" name="oxf.xforms.logging.debug">
        document
        model
        submission
        control
        event
        action
        analysis
        server
        html
        process
    </property>

    <property as="xs:NMTOKENS" name="oxf.xforms.logging.error">
        submission-error-body
    </property>

oxf.xforms.logging.debug controls what is logged at debug level:

Related to a particular XForms document:
- model
  - activity related to xf:model, including instance loads, validation, and binds
- submission
  - timing activity related to xf:submission
- submission-details
  - detail activity related to xf:submission
  - requires submission to be present as well
- control
  - activity related to controls
- event
  - activity related to events dispatching and propagation
- action
  - activity related to XForms actions
- document
  - other activity related to an XForms document
  - this includes the output of the <xf:message> action with level xxf:log-debug
- process
  - activity related to processes
Not related to a particular XForms document:
- analysis
  - activity related to the static analysis of an XForms document
- server
  - activity related to handling Ajax requests
- html
  - activity related to converting XForms to HTML
- resources
  - activity related to handling XForms CSS and JavaScript resources
- state
  - activity related to state handling
- resolver
  - activity related to the URI resolver
- utils
  - miscellaneous activity
- cache
  - [SINCE Orbeon Forms 4.6]
  - activity of the static state cache during XForms initialization
Data:
- html-static-state
  - requires html
  - outputs the static state input
- analysis-xbl-tree
  - requires analysis
  - outputs the detail of the XBL shadow trees computed
- submission-body
  - requires submission AND submission-details
  - outputs the detail of submission request/response bodies
- model-serialized-instance
  - requires model
  - outputs the full instances serialized into the dynamic state after an Ajax request completes
- server-body
  - requires server
  - outputs the full Ajax request and response bodies

oxf.xforms.logging.error controls what is logged at error level:

submission-error-body
- Whether to attempt to output a submission response body when a submission error occurs
- This is enabled by default, but you can turn it off, e.g. for data sensitivity reasons
- Binary bodies are not logged, but the logger mentions that the type is a binary type
- When the response body is NOT logged and is used for replace="instance|all", streaming is taking place. However when the response body IS logged, streaming does not take place:
  - The body is read in memory
  - The body is logged
  - Then the rest of the submission proceeds
server-body
- output the Ajax request in case of error occurring while processing the request

Development configuration

During XForms development, you might want to enable a more aggressive debug configuration.

Change your Log4j2 or Log4j configuration. In your WEB-INF/resources/config, check if you have a file named log4j2.xml or log4j.xml:

If you have a file named log4j2.xml (with 2 in the file name), inside the element <Loggers>, add:

<Logger name="org.orbeon.oxf.xforms.processor.XFormsServer" level="debug"/>
<Logger name="org.orbeon.oxf.processor.DebugProcessor"      level="debug"/>
<Logger name="org.orbeon.relational"                        level="debug"/>
<Logger name="org.orbeon.auth"                              level="debug"/>
<Logger name="org.orbeon.lifecycle"                         level="debug"/>

If you have a file named log4j.xml (without 2 in the file name), uncomment the following:

<category name="org.orbeon.oxf.xforms.processor.XFormsServer">
    <priority value="debug"/>
</category>

Configure the oxf.xforms.logging.debug property in your config/properties-local.xml. You can choose precisely what the XForms engine logs. The following is the most comprehensive configuration. It will log almost everything. In most cases, this is a good configuration during development, and while troubleshooting issues in staging:
```
<property as="xs:NMTOKENS" name="oxf.xforms.logging.debug">
    document
    model
    submission
    control
    event
    action
    analysis
    server
    server-body
    html
    process
    submission-details
    submission-body
    state
</property>
```

Production configuration

No debug output

In production, you probably don't want any debug information coming out to your logs. So set this in log4j.xml:

<category name="org.orbeon.oxf.xforms.processor.XFormsServer">
    <priority value="info"/>
</category>

Alternatively, remove or comment-out the lines above. When this is done, the oxf.xforms.logging.debug property is no longer used, so it does not matter what it contains. However, the oxf.xforms.logging.error is still relevant. Configure it appropriately, depending on whether you want to see submission responses bodies logged or not.

Just submission timings

If you only want to see submission timings, in your log4j.xml use:

<category name="org.orbeon.oxf.xforms.processor.XFormsServer">
    <priority value="debug"/>
</category>

And in your properties-local.xml:

<property as="xs:NMTOKENS" name="oxf.xforms.logging.debug">
    submission
</property>

Example output

The following shows a sample XForms logging session:

XForms server - start handling external events
  XForms server - start handling external event {target id: "age-input-control", event name: "xxforms-value-change-with-focus-change"}
    setvalue - setting instance value {value: "36", changed: "true", instance: "instance"}
    event - start dispatching {name: "xxforms-value-changed", id: "instance"}
    event - end dispatching {time (ms): "0"}
    event - start dispatching {name: "xforms-recalculate", id: "main-model"}
        model - start performing recalculate {model id: "main-model"}
          setvalue - setting instance value {value: "A", changed: "false", instance: "instance"}
          setvalue - setting instance value {value: "A", changed: "false", instance: "countries-instance"}
          setvalue - setting instance value {value: "", changed: "false", instance: "country-details-instance"}
        model - end performing recalculate {time (ms): "9"}
    event - end dispatching {time (ms): "9"}
    event - start dispatching {name: "xforms-revalidate", id: "main-model"}
        model - start performing revalidate {model id: "main-model"}
          event - start dispatching {name: "xxforms-invalid", id: "instance"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xxforms-valid", id: "resources-instance"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xxforms-valid", id: "flavors-instance"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xxforms-valid", id: "carriers-instance"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xxforms-valid", id: "countries-names-instance"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xxforms-valid", id: "countries-instance"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xxforms-valid", id: "country-details-instance"}
          event - end dispatching {time (ms): "0"}
        model - end performing revalidate {time (ms): "4"}
    event - end dispatching {time (ms): "4"}
    event - start dispatching {name: "xforms-refresh", id: "main-model"}
        model - start performing refresh {model id: "main-model"}
          controls - start cloning
          controls - end cloning {time (ms): "0"}
          controls - start updating bindings
          controls - end updating bindings {time (ms): "11", controls updated: "91", repeat iterations: "0"}
          event - start dispatching {name: "xforms-value-changed", id: "age-input-control"}
          event - end dispatching {time (ms): "0"}
          event - start dispatching {name: "xforms-enabled", id: "age-input-control"}
          event - end dispatching {time (ms): "0"}
        model - end performing refresh {time (ms): "17"}
    event - end dispatching {time (ms): "17"}
  XForms server - end handling external event {time (ms): "33"}
XForms server - end handling external events {time (ms): "33"}