Hi All,
Below is the exception which we get with Ratis 0.2.0
java.lang.NoSuchFieldError: CONTEXT_SPAN_KEY
at
org.apache.ratis.shaded.io.grpc.internal.CensusTracingModule$ServerTracer.filterContext(CensusTracingModule.java:340)
at
org.apache.ratis.shaded.io.grpc.internal.StatsTraceContext.serverFilterContext(StatsTraceContext.java:121)
at
org.apache.ratis.shaded.io.grpc.internal.ServerImpl$ServerTransportListenerImpl.createContext(ServerImpl.java:482)
at
org.apache.ratis.shaded.io.grpc.internal.ServerImpl$ServerTransportListenerImpl.streamCreated(ServerImpl.java:416)
<stack trace truncated>
The problem is because of two different definition of
io.opencensus.trace.unsafe.ContextUtils class present in the classpath. The
reason for having two different definition of ContextUtils in classpath is due
to the fact that we are shading/relocating io.grpc and not io.opencensus.
With shading we are generating the below definition which ends up in
ratis-proto-shaded jar
package io.opencensus.trace.unsafe;
import org.apache.ratis.shaded.io.grpc.Context;
import io.opencensus.trace.Span;
/**
* Util methods/functionality to interact with the {@link
org.apache.ratis.shaded.io.grpc.Context}.
*
* <p>Users must interact with the current Context via the public APIs in {@link
* io.opencensus.trace.Tracer} and avoid usages of the {@link
#CONTEXT_SPAN_KEY} directly.
*
* @since 0.5
*/
public final class ContextUtils {
// No instance of this class.
private ContextUtils() {}
/**
* The {@link org.apache.ratis.shaded.io.grpc.Context.Key} used to interact
with {@link org.apache.ratis.shaded.io.grpc.Context}.
*
* @since 0.5
*/
public static final Context.Key<Span> CONTEXT_SPAN_KEY =
Context.key("opencensus-trace-span-key");
}
Since we have added io.opencensus as direct dependency in ratis-grpc we get the
below definition in io.opencensus:opencensus-api:jar
package io.opencensus.trace.unsafe;
import io.grpc.Context;
import io.opencensus.trace.Span;
/**
* Util methods/functionality to interact with the {@link io.grpc.Context}.
*
* <p>Users must interact with the current Context via the public APIs in {@link
* io.opencensus.trace.Tracer} and avoid usages of the {@link
#CONTEXT_SPAN_KEY} directly.
*
* @since 0.5
*/
public final class ContextUtils {
// No instance of this class.
private ContextUtils() {}
/**
* The {@link io.grpc.Context.Key} used to interact with {@link
io.grpc.Context}.
*
* @since 0.5
*/
public static final Context.Key<Span> CONTEXT_SPAN_KEY =
Context.key("opencensus-trace-span-key");
}
Both of the jars end up in classpath and ContextUtils is getting loaded from
io.opencensus:opencensus-api:jar which is causing the problem.
The simple fix would be to remove the dependency of io.opencensus from
ratis-grpc/pom.xml (patch for the same is attached in this mail). This is not a
permanent fix, as any application might bring in
io.opencensus:opencensus-api:jar of its own.
We have to find a way to shade io.opencensus:opencensus-api:jar.
Note: from the comment in ratis-proto-shaded/pom.xml: Cannot relocate
io.opencensus due to AutoValue code generation
-Nanda
On 5/7/18, 3:28 PM, "Lokesh Jain" <lj...@hortonworks.com> wrote:
We found an issue while updating ozone to Ratis snapshot build
0.1.1-alpha-4309324-SNAPSHOT (https://issues.apache.org/jira/browse/HDDS-19). I
feel we should hold the release till this is fixed. Please let us know of your
opinion as well.
Thanks
Lokesh
