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https://issues.apache.org/jira/browse/HTRACE-279?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14955821#comment-14955821
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Colin Patrick McCabe commented on HTRACE-279:
---------------------------------------------
For some reason, the compiler won't accept {{SpanSerializer}} as an instance of
{{JsonSerializer<Span>}}.
{code}
public static class SpanSerializer extends JsonSerializer<Span> {
...
{code}
{code}
static {
// We must explicitly declare that we want to use the SpanSerializer from
// htrace-core4, or else Jackson sometimes forgets to use it, even though
// there is a @JsonSerializer annotation on the Span class. See HTRACE-279.
OBJECT_MAPPER = new ObjectMapper();
SimpleModule spanModule = new SimpleModule("SpanModule");
JsonSerializer<Span> spanSerializer = (JsonSerializer<Span>)new
Span.SpanSerializer();
spanModule.addSerializer(Span.class, spanSerializer);
OBJECT_MAPPER.registerModule(spanModule);
JSON_WRITER = OBJECT_MAPPER.writer();
}
{code}
{code}
[ERROR] Failed to execute goal
org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile (default-compile)
on project htrace-htraced: Compilation failure
[ERROR]
/home/cmccabe/src/htrace2f/htrace-htraced/src/main/java/org/apache/htrace/impl/RestBufferManager.java:[68,64]
error: inconvertible types
[ERROR] -> [Help 1]
{code}
I'm guessing that this is related to shading. I suppose in some sense the
{{JsonSerializer}} is not part of our public API, even though it's a public
class, since we're shading Jackson. I'm also guessing that we made a mistake
in declaring it as {{JsonSerializer<Span>}} rather than {{JsonSerializer<?
extends Span>}}, although I think this would still not fix the issue.
I guess we just have to use {{Span#toString}} for right now.
> Force HTraced span receiver to use SpanSerializer and add validation to
> htraced REST ingest path
> ------------------------------------------------------------------------------------------------
>
> Key: HTRACE-279
> URL: https://issues.apache.org/jira/browse/HTRACE-279
> Project: HTrace
> Issue Type: Bug
> Affects Versions: 4.1
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
>
> Apparently the HTracedReceiver is sometimes not using the JSON SpanSerializer
> from htrace-core4. We should force the span receiver to use that serializer.
> Also, we should add span ID validation to the htraced daemon. Currently, a
> bad span ID can crash the daemon, which is not very robust. These changes
> will fix the unit test failure in TestHTracedReceiver.
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