Dropwizard Metrics

[sheldon-sminq]

We are using Flexypool with HikariCP for our dropwizard app. We push our dropwizard metrics to a graphite server.

Wanted to push flexy pool metrics to the same graphite server, how do we proceed with the same. Can we pass the Dropwizard metrics registry to flexypool metric factory?

[vladmihalcea]

That's easy. FlexyPool supports both CodaHale Metrics and Dropwizard. However, the Dropwizard Metrics use the new io.dropwizard.metrics package which hasn't been released yet by Dropwizard.

So, you can use the CodahaleMetricsFactory like in this test case:

ReservoirFactory reservoirFactory = ...;

Configuration<DataSource> configuration = new Configuration.Builder<DataSource>(
    "unique", 
    dataSource, 
    poolAdapterFactory)
.setMetricsFactory(new CodahaleMetrics.ReservoirMetricsFactory(reservoirFactory))
.build();

[sheldon-sminq]

Is this also valid?

Configuration configuration = new Configuration.Builder( "unique", dataSource, poolAdapterFactory) .setMetricsFactory(new CodahaleMetricsFactoryService().load()) .build();

[vladmihalcea]

That can work too, but it will use a new MetricRegistry, not the one that you might already have. At least, that's what I thought you wanted in the first place.

[sheldon-sminq]

Yes actually want to use the existing metrics factory, but how do pass the existing MetricsFactory instance to FlexyPool?

    ReservoirFactory reservoirFactory = ?

[sheldon-sminq]

Also i am using Dropwizard 1.0.2

[vladmihalcea]

I guess, it's not possible now. However, it's not very difficult to add support for this feature. You'd just have to provide the MetricsFactory as Configuration parameter. Unfortunately, I don't have time to do it right now, but if you send me a Pull request, I would integrate it right away.

[vladmihalcea]

I released a new version 1.2.5. Now you can customize the MetricRegistry like this:

CodahaleMetrics codahaleMetrics = new CodahaleMetrics(
    configurationProperties, metricRegistry, reservoirFactory);

This way, you can do something like this:

Configuration<DataSource> configuration = new Configuration.Builder<DataSource>(
"unique", dataSource, poolAdapterFactory)
.setConnectionProxyFactory(connectionProxyFactory)
.setJmxAutoStart(true)
.setJmxEnabled(true)
.setMetricLogReporterMillis(120)
.setMetricsFactory(new MetricsFactory() {
    @Override
    public Metrics newInstance(ConfigurationProperties configurationProperties) {
        return new CodahaleMetrics(configurationProperties, metricRegistry, new ReservoirFactory() {
            @Override
            public Reservoir newInstance(Class<? extends Metric> metricClass, String metricName) {
                return new ExponentiallyDecayingReservoir();
            }
        });
    }
})
.build();

There's this ConfigurationTest unit test that you can run and see how it works.

[rripken]

Is there a way to do something like your example above but from a Spring xml config?

[vladmihalcea]

Yes, of course. In the documentation and source code you can find XML configuration examples.

[rripken]

Could you suggest an example I should look at? I downloaded the entire repo and looked at all the *.xml files and I didn't see any that showed passing a metricRegistry into Flexypool. Did I miss it? Do I need to create my own MetricsFactory implementation to be able to pass a metricRegistry in?

[vladmihalcea]

Like this:

Configuration<DataSource> configuration = new Configuration.Builder<DataSource>(
"unique", dataSource, poolAdapterFactory)
.setConnectionProxyFactory(connectionProxyFactory)
.setJmxAutoStart(true)
.setJmxEnabled(true)
.setMetricLogReporterMillis(120)
.setMetricsFactory(new MetricsFactory() {
    @Override
    public Metrics newInstance(ConfigurationProperties configurationProperties) {
        return new CodahaleMetrics(configurationProperties, metricRegistry, new ReservoirFactory() {
            @Override
            public Reservoir newInstance(Class<? extends Metric> metricClass, String metricName) {
                return new ExponentiallyDecayingReservoir();
            }
        });
    }
})
.build();

You can translate this into XML too. Likee any other Spring XML configuration. Of course, it's much simpler with Java-based configs, but doable in XML too.

For instance, a simple XML config looks slike this:

<bean id="configurationBuilder" class="com.vladmihalcea.flexypool.config.Configuration$Builder">
    <constructor-arg value="uniqueId"/>
    <constructor-arg ref="poolingDataSource"/>
    <constructor-arg value="#{ T(com.vladmihalcea.flexypool.adaptor.BoneCPPoolAdapter).FACTORY }"/>
</bean>

<bean id="configuration" factory-bean="configurationBuilder" factory-method="build"/>

<bean id="dataSource" class="com.vladmihalcea.flexypool.FlexyPoolDataSource" init-method="start" destroy-method="stop">
    <constructor-arg ref="configuration"/>
    <constructor-arg>
        <array>
            <bean class="com.vladmihalcea.flexypool.strategy.RetryConnectionAcquiringStrategy.Factory">
                <constructor-arg value="2"/>
            </bean>
        </array>
    </constructor-arg>
</bean>

You can also pass a MetricsFactory if you want. Just encapsulate that in a dedicated class and instantiate that instead.

But why would you want to do that? Do you want to change the default configs? You can also do some behavior changes through the config properties that are also documented.

[rripken]

I haven't seen how to create an anonymous inner class in an xml config. I'll do some googling, thanks.

[vladmihalcea]

I just told you that you don't have to create an anonymous inner class in XML. Create a proper class that extends that interface and use that class to configure it in XML.

[rripken]

Yeah, ok. That sounds perfect - I'll do that. Thanks!

[vladmihalcea]

Great. When you're done, you can send me a Pull Request with an update to the documentation which presents this use case. Add a test case in the flexy-pool-core module that demonstrates it's all working as well.