Log transporter

Normally, each adapter writes its messages viathis.log The message is written to the log file, and that's it. However, some adapters need the messages themselves: the administrator displays them in the logs , others write them to a database, or forward them. This is where the log transporter comes in.

For your own logging purposes, this is sufficient.this.log.info(...) This page describes the special case where one adapter wants to read the messages of all others .

Turn on

In theio-package.json in the blockcommon :

"logTransporter": true

Only then is the method availablerequireLog It is not available at all. It is enabled in the adapter code and the eventlog subscribed:

async onReady() {
    await this.requireLog(true);
}

onLog(logObject) {
    // logObject.severity, .message, .from, .ts, ._id
}

The handler is bound in the constructor like the others:

this.on('log', this.onLog.bind(this));

Structure of a message

Example:

{ _id: 4711, from: 'testlog.0', message: 'testlog.0 (12504) adapter disabled',
  severity: 'error', ts: 1585413238439 }

What's happening in the background

Does an adapter carry the featurelogTransporter , the js-controller sets the state for each instancesystem.adapter.<name>.<instanz>.logging on. Does the adapter place it overrequireLog(true) ontrue , thereby announcing: I want the reports.

All other instances observe the conditions.*.logging As soon as one of them landstrue If the message is in a FIFO queue, it will also be written to that recipient. The recipient reads it and receives it as an event.log delivered.

!>requireLog(false) It doesn't work immediately. The other instances only stop delivering after about ten seconds.

What's the point of that?

• This allows the administrator to view the logs live without reading the file.
• Adapters likesql ortelegram This allows them to forward error messages.
• An adapter that only wants to handle its own messages doesn't need that: it simply writes the data itself during the logging process.

If you want to reach the user about a specific event, instead of reading every message, you are better off using notifications .