Allow disabling dtrace-provider

[robertrossmann]

This allows people using Node.js >=6 to avoid a bunch of deprecation warnings coming from the C/C++ land in dtrace-provider which uses deprecated APIs.

Usage: Just set BUNYAN_NO_DTRACE to a truthy value and you are all set.

Recommended changelog entry:

• Allow disabling DTrace support via BUNYAN_NO_DTRACE environment variable

Thanks for review!

[trentm]

@Alaneor Sorry for the delay in responding.

What deprecation warnings? Perhaps this is specific to a particular node v6 version or a particular platform? Here is me runnign this on Mac 10.11.4 with node 6.2.2:

[trentm@danger0:~/tm/node-bunyan (master)]
$ node --version
v6.2.2

[trentm@danger0:~/tm/node-bunyan (master)]
$ rm -rf node_modules/

[trentm@danger0:~/tm/node-bunyan (master)]
$ npm install
npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue

> dtrace-provider@0.6.0 install /Users/trentm/tm/node-bunyan/node_modules/dtrace-provider
> node scripts/install.js

bunyan@1.8.2 /Users/trentm/tm/node-bunyan
├── ben@0.0.0
...
  └── extsprintf@1.0.0

[trentm@danger0:~/tm/node-bunyan (master)]
$ node examples/hi.js
log.info() is: true
{"name":"myapp","hostname":"danger0.local","pid":49087,"level":30,"msg":"hi","time":"2016-07-05T05:44:54.641Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":10},"v":0}
{"name":"myapp","hostname":"danger0.local","pid":49087,"level":30,"msg":"hi trent","time":"2016-07-05T05:44:54.643Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":11},"v":0}
{"name":"myapp","hostname":"danger0.local","pid":49087,"level":30,"msg":"hi true there","time":"2016-07-05T05:44:54.643Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":12},"v":0}
{"name":"myapp","hostname":"danger0.local","pid":49087,"level":30,"foo":"bar","multiline":"one\ntwo\nthree","msg":"hi 1 two 3","time":"2016-07-05T05:44:54.644Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":15},"v":0}


{"name":"myapp","hostname":"danger0.local","pid":49087,"component":"wuzzle","level":30,"msg":"creating a wuzzle","time":"2016-07-05T05:44:54.645Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":23,"func":"Wuzzle"},"v":0}
{"name":"myapp","hostname":"danger0.local","pid":49087,"component":"wuzzle","level":40,"msg":"This wuzzle is woosey.","time":"2016-07-05T05:44:54.645Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":27,"func":"Wuzzle.woos"},"v":0}
{"name":"myapp","hostname":"danger0.local","pid":49087,"level":30,"msg":"done with the wuzzle","time":"2016-07-05T05:44:54.645Z","src":{"file":"/Users/trentm/tm/node-bunyan/examples/hi.js","line":32},"v":0}

[ltvolks]

OS: OSX 10.10.5
Node: 6.2.2
Bunyan: 1.8.0

After switching to 6.2.2 from 5.10.1, I began to see Dtrace-related errors like:

Error: Module version mismatch. Expected 48, got 47.
    at Error (native)
    at Object.Module._extensions..node (module.js:568:18)

<snip>

{ Error: Cannot find module './build/default/DTraceProviderBindings'
    at Function.Module._resolveFilename (module.js:440:15)

<snip>

{ Error: Cannot find module './build/Debug/DTraceProviderBindings'
    at Function.Module._resolveFilename (module.js:440:15)

After performing an npm rebuild, I began to see stack traces including deprecation warnings similar to these, which may be what @Alaneor is referring to:

==== C stack trace ===============================

 1: v8::Template::Set(v8::Local<v8::Name>, v8::Local<v8::Data>, v8::PropertyAttribute)
 <snip v8 calls>
 7: 0xbb66510961b
(node) v8::ObjectTemplate::Set() with non-primitive values is deprecated
(node) and will stop working in the next major release.

==== JS stack trace =========================================

Security context: 0x2c4cd92c9e59 <JS Object>#0#
    1: .node [module.js:568] [pc=0xbb66536d1a4] (this=0x14725d4c7ae9 <an Object with map 0x8501ea17d41>#1#,module=0x1d7b644f5921 <a Module with map 0x8501ea18319>#2#,filename=0x1d7b644f5889 <String[128]: /sandbox/node_modules/dtrace-provider/build/Release/DTraceProviderBindings.node>)
    2: load [module.js:~449] [pc=0xbb6654aca76] (this=0x1d7b644f5921 <a Module with map 0x8501ea18319>#2#,filename=0x1d7b644f5889 <String[128]: /sandbox/node_modules/dtrace-provider/build/Release/DTraceProviderBindings.node>)

<snip more of the same Dtrace-related stack>

In the end, I rm -rf /node_modules and reinstalled my dependencies, resolving the errors.

[robertrossmann]

The deprecation warnings this patch was supposed to avoid are described in this issue. However, the root cause seems to have been fixed upstream (nan) so I do not think this is needed anymore.

I keep this open in case you would be interested to merge it anyway as a means to disable the DTrace functionality completely, perhaps to let users get some small perf boost. Otherwise, feel free to close. Thanks!

[robertrossmann]

Closing due to no interest to merge this from the Bunyan team.

The original reason for disabling DTrace has been fixed in #449, but disabling it might have improved performance a bit.