public void Should_RemoveNodeMetricsAndDisposeMetricsContext_When_HostIsRemoved()
{
var metricsRoot = new App.Metrics.MetricsBuilder().Build();
try
{
var cluster = GetNewCluster(b => b.WithMetrics(metricsRoot.CreateDriverMetricsProvider()));
var session = cluster.Connect();
var metrics = session.GetMetrics();
Assert.AreEqual(3, cluster.Metadata.Hosts.Count);
Assert.AreEqual(3, metrics.NodeMetrics.Count);
// get address for host that will be removed from the cluster in this test
var address = TestCluster.ClusterIpPrefix + "2";
var hostToBeRemoved = cluster.Metadata.Hosts.First(h => h.Address.Address.Equals(IPAddress.Parse(address)));
// check node metrics are valid
var gauge = metrics.GetNodeGauge(hostToBeRemoved, NodeMetric.Gauges.OpenConnections);
var appMetricsGaugeValue = metricsRoot.Snapshot.GetGaugeValue(gauge.Context, gauge.Name);
Assert.Greater(gauge.GetValue().Value, 0);
Assert.AreEqual(gauge.GetValue().Value, appMetricsGaugeValue);
// check node metrics context in app metrics is valid
var context = metricsRoot.Snapshot.GetForContext(gauge.Context);
Assert.True(context.IsNotEmpty());
Assert.AreEqual(2, context.Gauges.Count());
// remove host from cluster
TestCluster.DecommissionNode(2);
TestCluster.Stop(2);
try
{
TestHelper.RetryAssert(() => { Assert.AreEqual(2, cluster.Metadata.Hosts.Count, "metadata hosts count failed"); }, 200, 50);
TestHelper.RetryAssert(() => { Assert.AreEqual(2, metrics.NodeMetrics.Count, "Node metrics count failed"); }, 10, 500);
}
catch
{
TestCluster.Start(2, "--jvm_arg=\"-Dcassandra.override_decommission=true\"");
throw;
}
// Check node's metrics were removed from app metrics registry
context = metricsRoot.Snapshot.GetForContext(gauge.Context);
Assert.False(context.IsNotEmpty());
Assert.AreEqual(0, context.Gauges.Count());
TestCluster.Start(2, "--jvm_arg=\"-Dcassandra.override_decommission=true\"");
TestHelper.RetryAssert(() => { Assert.AreEqual(3, cluster.Metadata.Hosts.Count, "metadata hosts count after bootstrap failed"); },
200, 50);
// when new host is chosen by LBP, connection pool is created
foreach (var _ in Enumerable.Range(0, 5))
{
session.Execute("SELECT * FROM system.local");
}
TestHelper.RetryAssert(() => { Assert.AreEqual(3, metrics.NodeMetrics.Count, "Node metrics count after bootstrap failed"); }, 10,
500);
// Check node's metrics were added again
context = metricsRoot.Snapshot.GetForContext(gauge.Context);
Assert.True(context.IsNotEmpty());
Assert.AreEqual(2, context.Gauges.Count());
}
finally
{
metricsRoot.Manage.Disable();
}
}