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v2.6.0

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@kjin kjin released this 02 Apr 21:09
· 537 commits to main since this release
v2.6.0
0236217

2018-03-30, Version 2.6.0 (Beta), @kjin

This version introduces non-null spans, a new plugin loading mechanism, revised log messages and changes to pg tracing support (now including version 7).

Notable Changes

Non-Null Spans

SpanData objects passed by traceApi.runInRootSpan and returned by traceApi.createChildSpan are guaranteed to be non-null, whereas they previously could be null if either (1) they weren't created because of tracing policy decisions (an untraced span) or (2) an attempt to create the span was made in a place where it was impossible to determine on behalf of which incoming request they were tracing (an uncorrelated span). In other words:

const traceApi = require('@google-cloud/trace-agent').start();
traceApi.runInRootSpan({ name: 'my-custom-span' }, (rootSpan) => {
  if (!rootSpan) {
    // This code path will no longer execute.
  }
  const childSpan = traceApi.createChildSpan({ name: 'my-custom-smaller-span' });
  if (!childSpan) {
    // This code path will no longer execute.
  }
  // ...
});

Instead, "phantom" SpanData will be returned, which expose an identical, but non-functional API to that of a "real" SpanData object. The purpose of this change is to alleviate the burden of having branching code paths based on whether your code was being traced or not -- you may now assume that functions such as addLabel and endSpan are always on the given SpanData object.

If you must execute a separate code path based on whether your code is being traced or not, you may now use traceApi.isRealSpan:

const traceApi = require('@google-cloud/trace-agent').start();
traceApi.runInRootSpan({ name: 'my-custom-span' }, (rootSpan) => {
  if (!traceApi.isRealSpan(rootSpan)) {
    // Some code that should be executed because this request is not being traced.
  }
  const childSpan = traceApi.createChildSpan({ name: 'my-custom-smaller-span' });
  if (!traceApi.isRealSpan(childSpan)) {
    // Alternatively, you may directly check whether a span is untraced or uncorrelated.
    if (childSpan.type === traceApi.spanTypes.UNCORRELATED) {
      // Some code that should be executed because we lost context.
    } else if (childSpan.type === traceApi.spanTypes.UNTRACED) {
      // Some code that should be executed because the request was not sampled
      // (or otherwise disallowed by the tracing policy).
    }
  }
  // ...
});

This affects both plugins and the custom tracing API. All built-in tracing plugins have been changed correspondingly.

Log Messages

All logging output has been revised for consistency, and now include class/function names, as well as parameters in [square brackets].

Plugin Loader

The plugin loading mechanism has been completely re-written. There should be no observable changes (please file an issue if you encounter one.) The re-write fixes an issue where plugins can't patch modules with circular dependencies correctly (#618).

Tracing pg

We now support tracing for pg versions 6 - 7.

For consistency between tracing version 6 and 7, span labels in pg (when config.enhancedDatabaseReporting is enabled) now contain pre-processed query values rather than post-processed values.

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