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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.cassandra.tracing;
import java.net.InetAddress;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import com.google.common.collect.ImmutableMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import io.netty.util.concurrent.FastThreadLocal;
import org.apache.cassandra.concurrent.ExecutorLocal;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.marshal.TimeUUIDType;
import org.apache.cassandra.net.MessageIn;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.JVMStabilityInspector;
import org.apache.cassandra.utils.UUIDGen;
/**
* A trace session context. Able to track and store trace sessions. A session is usually a user initiated query, and may
* have multiple local and remote events before it is completed.
*/
public abstract class Tracing implements ExecutorLocal
{
public static final String TRACE_HEADER = "TraceSession";
public static final String TRACE_TYPE = "TraceType";
public enum TraceType
{
NONE,
QUERY,
REPAIR;
private static final TraceType[] ALL_VALUES = values();
public static TraceType deserialize(byte b)
{
if (b < 0 || ALL_VALUES.length <= b)
return NONE;
return ALL_VALUES[b];
}
public static byte serialize(TraceType value)
{
return (byte) value.ordinal();
}
private static final int[] TTLS = { DatabaseDescriptor.getTracetypeQueryTTL(),
DatabaseDescriptor.getTracetypeQueryTTL(),
DatabaseDescriptor.getTracetypeRepairTTL() };
public int getTTL()
{
return TTLS[ordinal()];
}
}
protected static final Logger logger = LoggerFactory.getLogger(Tracing.class);
private final InetAddress localAddress = FBUtilities.getLocalAddress();
private final FastThreadLocal state = new FastThreadLocal<>();
protected final ConcurrentMap sessions = new ConcurrentHashMap<>();
public static final Tracing instance;
static
{
Tracing tracing = null;
String customTracingClass = System.getProperty("cassandra.custom_tracing_class");
if (null != customTracingClass)
{
try
{
tracing = FBUtilities.construct(customTracingClass, "Tracing");
logger.info("Using {} as tracing queries (as requested with -Dcassandra.custom_tracing_class)", customTracingClass);
}
catch (Exception e)
{
JVMStabilityInspector.inspectThrowable(e);
logger.error(String.format("Cannot use class %s for tracing, ignoring by defaulting to normal tracing", customTracingClass), e);
}
}
instance = null != tracing ? tracing : new TracingImpl();
}
public UUID getSessionId()
{
assert isTracing();
return state.get().sessionId;
}
public TraceType getTraceType()
{
assert isTracing();
return state.get().traceType;
}
public int getTTL()
{
assert isTracing();
return state.get().ttl;
}
/**
* Indicates if the current thread's execution is being traced.
*/
public static boolean isTracing()
{
return instance.get() != null;
}
public UUID newSession(Map customPayload)
{
return newSession(
TimeUUIDType.instance.compose(ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes())),
TraceType.QUERY,
customPayload);
}
public UUID newSession(TraceType traceType)
{
return newSession(
TimeUUIDType.instance.compose(ByteBuffer.wrap(UUIDGen.getTimeUUIDBytes())),
traceType,
Collections.EMPTY_MAP);
}
public UUID newSession(UUID sessionId, Map customPayload)
{
return newSession(sessionId, TraceType.QUERY, customPayload);
}
/** This method is intended to be overridden in tracing implementations that need access to the customPayload */
protected UUID newSession(UUID sessionId, TraceType traceType, Map customPayload)
{
assert get() == null;
TraceState ts = newTraceState(localAddress, sessionId, traceType);
set(ts);
sessions.put(sessionId, ts);
return sessionId;
}
public void doneWithNonLocalSession(TraceState state)
{
if (state.releaseReference() == 0)
sessions.remove(state.sessionId);
}
/**
* Stop the session and record its complete. Called by coodinator when request is complete.
*/
public void stopSession()
{
TraceState state = get();
if (state == null) // inline isTracing to avoid implicit two calls to state.get()
{
logger.trace("request complete");
}
else
{
stopSessionImpl();
state.stop();
sessions.remove(state.sessionId);
set(null);
}
}
protected abstract void stopSessionImpl();
public TraceState get()
{
return state.get();
}
public TraceState get(UUID sessionId)
{
return sessions.get(sessionId);
}
public void set(final TraceState tls)
{
state.set(tls);
}
public TraceState begin(final String request, final Map parameters)
{
return begin(request, null, parameters);
}
public abstract TraceState begin(String request, InetAddress client, Map parameters);
/**
* Determines the tracing context from a message. Does NOT set the threadlocal state.
*
* @param message The internode message
*/
public TraceState initializeFromMessage(final MessageIn message)
{
final byte[] sessionBytes = message.parameters.get(TRACE_HEADER);
if (sessionBytes == null)
return null;
assert sessionBytes.length == 16;
UUID sessionId = UUIDGen.getUUID(ByteBuffer.wrap(sessionBytes));
TraceState ts = get(sessionId);
if (ts != null && ts.acquireReference())
return ts;
byte[] tmpBytes;
TraceType traceType = TraceType.QUERY;
if ((tmpBytes = message.parameters.get(TRACE_TYPE)) != null)
traceType = TraceType.deserialize(tmpBytes[0]);
if (message.verb == MessagingService.Verb.REQUEST_RESPONSE)
{
// received a message for a session we've already closed out. see CASSANDRA-5668
return new ExpiredTraceState(newTraceState(message.from, sessionId, traceType));
}
else
{
ts = newTraceState(message.from, sessionId, traceType);
sessions.put(sessionId, ts);
return ts;
}
}
public Map getTraceHeaders()
{
assert isTracing();
return ImmutableMap.of(
TRACE_HEADER, UUIDGen.decompose(Tracing.instance.getSessionId()),
TRACE_TYPE, new byte[] { Tracing.TraceType.serialize(Tracing.instance.getTraceType()) });
}
protected abstract TraceState newTraceState(InetAddress coordinator, UUID sessionId, Tracing.TraceType traceType);
// repair just gets a varargs method since it's so heavyweight anyway
public static void traceRepair(String format, Object... args)
{
final TraceState state = instance.get();
if (state == null) // inline isTracing to avoid implicit two calls to state.get()
return;
state.trace(format, args);
}
// normal traces get zero-, one-, and two-argument overloads so common case doesn't need to create varargs array
public static void trace(String message)
{
final TraceState state = instance.get();
if (state == null) // inline isTracing to avoid implicit two calls to state.get()
return;
state.trace(message);
}
public static void trace(String format, Object arg)
{
final TraceState state = instance.get();
if (state == null) // inline isTracing to avoid implicit two calls to state.get()
return;
state.trace(format, arg);
}
public static void trace(String format, Object arg1, Object arg2)
{
final TraceState state = instance.get();
if (state == null) // inline isTracing to avoid implicit two calls to state.get()
return;
state.trace(format, arg1, arg2);
}
public static void trace(String format, Object... args)
{
final TraceState state = instance.get();
if (state == null) // inline isTracing to avoid implicit two calls to state.get()
return;
state.trace(format, args);
}
/**
* Called from {@link org.apache.cassandra.net.OutboundTcpConnection} for non-local traces (traces
* that are not initiated by local node == coordinator).
*/
public abstract void trace(ByteBuffer sessionId, String message, int ttl);
}