CASSANDRA-19447 Register the measurements of the bootstrap as Dropwizard metrics

[Mmuzaf]

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The Cassandra Jira

[smiklosovic]

is this ... ok? why cant we put this to e.g. init()

[Mmuzaf]

The metrics should only be registered once, when the class is inited. However, since it relies on the local counters, e.g. bootstrapFilesTotal, it is easier to register them as static variables.

[smiklosovic]

what do you think about changing init() to accept listeners... (might be on varargs)

in StorageService we do

    bootstrapper.init();
    bootstrapper.addProgressListener(progressSupport);

could not we do all of this in init() ?

[smiklosovic]

btw is it safe if somebody, by accident, calls this method twice? what would happen then?

[Mmuzaf]

We can have only one bootstrap process running, there is a check for that:

        BootStrapper bootstrapper = new BootStrapper(getBroadcastAddressAndPort(), metadata, movements, strictMovements);
        boolean res = ongoingBootstrap.compareAndSet(null, bootstrapper);
        if (!res)
            throw new IllegalStateException("Bootstrap can be started exactly once, but seems to have already started: " + bootstrapper);

Anyway, I've moved the init to the constructor, so it should be clearer now.