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Broadcast Log Message

A-Stack allows users to provide facet id on which all the log messages can be broadcast.

Error Handling in Applications

Error handling is critical aspect of developing applications in any programming language. Error handling is a mechanism where applications can notify error conditions to end users. A-Stack is a collection of number of atomic domain languages, the error handling varies based on language the application is using. Error handling in A-Stack can be classified into three broad categories -

• Error handling in NewFacetInstances
• Error handling as part of process code in non-workflow definition language.
• Error handling in Workflow Definition Language

Trapping Errors in NewFacetInstances

A-Stack provides <OnError> event as part of Facet life-cycle which can be used 

Trapping Errors in Queries

A-Stack Error handling mechanism can be used to trap errors 

To Configure broadcast of message:

<SffLocalConfig><Query>
  <SetLocalData key="ErrorHandler">
    <Value>
      <SetResponseData>
        <Key>
          <sffMessage.log.broadcast.all>loggerfacet</sff.log.broadcast.all>
    <sff.log.broadcast.message>json</sff.log.broadcast.message>
</SffLocalConfig>Value.Error
        </Key>
        <Value>
          [:$Error:]
        </Value>
      </SetResponseData>
    </Value>
  </SetLocalData>
  <Find Format="Version">
    <VendorInfo1>
      <vendorId>
        <NE>
        </NE>
      </vendorId>
    </VendorInfo1>
  </Find>
</Query>

Explanation

• sff.log.broadcast.<log level name> which defines one or more facet IDs used for log broadcasting. That is:
  •  <sff.log.broadcast.error>[:MyErrorsFacet:]</sff.log.broadcast.error> - This one will broadcast log error messages to [randomized] [:MyErrorsFacet:] fid 
  • <sff.log.broadcast.all>wstest</sff.log.broadcast.all> - This one will log messages to wstest fid.
    You can specify more than one fid as comma-separated list.
  • Known Log levels are: 
  1. 1. text
     2. trace
     3. debug
     4. info
     5. warn
     6. error
     7. fatal
     8. all

• sff.log.broadcast.protocol. Default value is “ws,wss”. This is the list of protocols which will be used to select broadcast pipelines. That is, it will *not* broadcast on HTTP connections, for example. When broadcast is enabled, startup will log the list of protocols so you know it was enabled. Obviously, it will *not* print the list of facet IDs used for broadcast.

• sff.log.broadcast.message. This is log message definition. It may come in different forms:

• <sff.log.broadcast.message>json<sff.log.broadcast.message> This simplest form allows you to define log message type (e.g. xml or json). Default is xml.

• Default message in JSON format will look like this:

  Code Block
  language text title Default Message linenumbers true
  { "Log": { "Level":"WARN", "Source":"SffSequenceFacet", "Timestamp":1479334740055, "Message":"startSchedularForMonitorStatus:MonitorStatus 1:0 @ Wed Nov 16 14:19:00 PST 2016: Scheduled: skip past (-55 ms) event for Wed Nov 16 14:19:00 PST 2016 [0../30sec]" } }

  In XML Format:

  Code Block
  language xml title Default Message linenumbers true
  <Log> <Level>WARN</Level> <Source>SffSequenceFacet</Source> <Timestamp>1479334740055<Timestamp> <Message>startSchedularForMonitorStatus:MonitorStatus 1:0 @ Wed Nov 16 14:19:00 PST 2016: Scheduled: skip past (-55 ms) event for Wed Nov 16 14:19:00 PST 2016 [0../30sec]</Message> </Log>

  
  Log messages are automatically added to the logger window on TQLConsole

...