OpenCensus spans cap number of attributes at 32

[jdbennet2001]

Please answer these questions before submitting a bug report.

What version of OpenCensus are you using?

0.0.16

What version of Node are you using?

10.x

What did you do?

If possible, provide a recipe for reproducing the error.
Generate a child span, and add more than 32 attributes

  let span     = tracer.startChildSpan({name, kind: 2});
  let i = 0;
  for ( ; i < 35; i++ ){ 
      span.addAttribute(`attr ${i}`, i);
 }

What did you expect to see?

All attributes show up in Jaeger

What did you see instead?

Only 32 attributes are preserved.

Additional context

There appears to be a maximum number of attributes for each span, set here:
https://github.com/census-instrumentation/opencensus-node/blob/b2726345ccb3b97e87bf29bb18c50c7486b1e560/packages/opencensus-core/src/trace/sampler/sampler.ts#L131
Is there a reason why the maximum is set to 32?

[mayurkale22]

Thanks for reporting this! We define limits on the number of attributes, annotations, message events and links on each span in order to prevent an unbounded memory increase for long-running spans: https://github.com/census-instrumentation/opencensus-specs/blob/master/trace/TraceConfig.md#limits. What do you think about this?

[jdbennet2001]

I have an end user who needs more than 32 attributes.

The docs say:

Implementations should provide a way to override the globals per-span.

I would assume that this would work, but the limit cannot be increased..

const monitor = tracing.start({
  exporter: exportRouter,
  propagation: b3,
  plugins: {
    http: {
      module: '@opencensus/instrumentation-http',
      config: {
        applyCustomAttributesOnSpan: customAttributeFunction,
      },
    },
  },
  traceParams : { numberOfAttributesPerSpan : 64}
});

Is there an approved way for client code to update this value?

[mayurkale22]

Implementations should provide a way to override the globals per-span.

Yes, correct. I will open PR to fix it

[mayurkale22]

Hey @jdbennet2001 are you waiting on a new release with this fix? I will be more than happy to release a new version.

[jdbennet2001]

I am eagerly waiting for a new release to roll out the code. Thank you for following up.

[mayurkale22]

Just for your information, I am waiting on #644 and #647, If I don't get any update on those (may be till tomorrow) I will cut a new release.

[mayurkale22]

@jdbennet2001 Published in 0.0.17, let us know if you encounter any issues!

[jdbennet2001]

Update: I've tested with no issue and am rolling the fix out. Thanks for all the help!

[mayurkale22]

@jdbennet2001 thanks for the confirmation, glad to help you :)