Messages refactoring

[bertfrees]

Summary of the changes:

• Generalize VALIDATION_FAIL to FAIL

  see issue https://github.com/daisy/pipeline-framework/issues/121

• Find "status" port based on the media-type "application/vnd.pipeline.status+xml"

  See https://github.com/daisy/pipeline-framework/issues/122

• Fix "unsetPropertyPublisherFactory" error

  see https://github.com/daisy/xproc-maven-plugin/issues/23

• Properly support StreamResults in XProcOutput

  Previously each provided Result was being replaced with a newly created Result based on its systemId. Changed that so that Results are not replaced anymore if they are of type StreamResult.

• Improve exception handling

  • Adapt to improved exception handling in Calabash (see https://github.com/daisy/xmlcalabash1/pull/1)
    • Calabash does not send error messages to us anymore. The messages are embedded in the exceptions that Calabash throws.
    • XProcException.getLocator() returns a SourceLocator[] array which represents the stack trace of the XProc error.
  • When a Calabash exception is caught in the framework, send the error message to the client and provide more details in a debug message. As a rule, XProc errors should be caught within XProc code.
  • Enable line numbering in Saxon to get more detailed error info

• Refactoring of messages API

  • Remove the MessageBuilder.withSequence method because the sequence numbers of messages belonging to a certain job are supposed to follow each other so requiring the message creator to set it makes little sense. Messages may actually come from several sources. The sequence numbers are now computed automatically within MessageBuilder itself.
  • Automatically add message time stamp.
  • Add a new "ProgressMessage" class. It extends Message and adds support for nested messages and progress information. Nested messages will come from Calabash's new openStep/closeStep API, and progress information will come from the new custom px:progress attributes in XProc, but these can in theory also be provided by Java steps/functions directly through the Java API. The class also implement the SLF4J Logger API (log messages will be added as child messages).
  • Remove EventBusProvider from the public API and replace it with listen/unlisten methods in MessageAccessor. EventBusProvider is reserved for internal use now.
  • Add progress to the MessageAccessor API.
  • Support nested messages and progress information in the webservice. The "messages" element now has a "progress" attribute and is always present when the job is running, even when there are no new messages. "message" elements may now have "progress" and "portion" attributes and may have child "message" elements.
  • In calabash-adapter, don't create a EventBusMessageListener if the job ID is null.
  • Remove the MessageBuilderFactory class.
  • In push-notifier, make use of MessageAccessor API instead of EventBusProvider. EventBusProvider is still used for status updates.

• Changes to job XML

  • Add "msgSeq" attribute to messages when the messages were filtered by sequence number.
  • Add results element only if results present.

• Support sending messages to execution log from Java

  The system automatically associates messages with the current job. This is done using the same MDC based principle that is already used in IgnoreSiftAppender, the class responsible for logging different jobs to different log files.

  For convenience, the event bus now also implements the SLF4J Logger API.

• Support posting messages to EventBus through SLF4J

  without needing direct access to the EventBus. This happens via a custom Logback appender.

  This feature is intended mainly for channelling log messages from external libraries to the execution log.

  It also follows the proposal of unifying the two types of messages (execution log and detailed log) through one and the same mechanism, except that XProc/XSLT messages are still sent directly to the EventBus: see issue https://github.com/daisy/pipeline-issues/issues/478.

• logging-activator: enable all JUL log levels

  This can be done without a performance penalty because we are using LevelChangePropagator (https://logback.qos.ch/manual/configuration.html#LevelChangePropagator).

• Drop CallbackRegistry indirection

• Added a lot of tests

Depends on

• https://github.com/daisy/xmlcalabash1/pull/1
• https://github.com/daisy/pipeline-build-utils/pull/42

Can be tested on https://github.com/daisy/pipeline/compare/messages.

[bertfrees]

@rdeltour Travis does not seem to build this branch. Do you know why? .travis.yml says branches: {only: [master]}, but this is also the case for other repos where Travis does build.

[bertfrees]

A more in-depth review would be nice, yes. Of all the PR's this is the main one, the one with the most significant changes. I have added a summary.