The document discusses tracing transactions in Node.js applications, focusing on user interactions, data flow, and request handling. It includes code examples for wrapping HTTP requests and database update operations, as well as challenges related to callback functions. Additional resources are provided for further reading and job opportunities.

1. Beyond Profilers:
Tracing Node.js Transactions
TR Jordan
October 2014

2. users
users’ data

3. users
browser
internet
webserver
application
database cache
external API

4. users
browser
internet
webserver
application
database cache
external API

5. Throughput vs. Network Capacity

6. users
browser
internet
webserver
application
database cache
external API

11. users
browser
internet
webserver
application
database cache
external API

12. Request ID
+
Operation IDs
+
Other Stuff™

18. Code

19. var http = require('http');
var shimmer = require('shimmer');
shimmer.wrap(http, 'request', function
(original) {
return function () {
console.log("Starting request!");
var returned = original.apply(this,
arguments)
console.log("Done setting up request");
return returned;
};
});

20. shimmer.wrap(collection.prototype, 'update',
function (fn) {
return function (query, doc, options, callback) {
if (typeof options === 'function') {
callback = options
options = {}
}
var run = fn.bind(this, query, doc, options)
return attempt(run, this.collectionName,
this.db, {
QueryOp: 'update',
Query: JSON.stringify(query),
Update_Document: JSON.stringify(doc)
}, callback)
}
})

21. Challenges

22. Initial Function
Callback
Callback
Callback
Callback
User

23. Initial Function
Callback
Callback
Callback
Callback
User

24. Node
Work Queue Callback

25. C++ Node OS
Work Queue Callback

27. Initial Function
Callback
Callback
Callback
Callback
User

28. Tracelyzer via UDP

29. Tracelyzer via UDP
5
0
0

30. Thanks!
Connect.
@_tr
tjordan@appneta.com
Read.
• On the Blog:
happneta.com/blog/x-trace-introduction/
• On GitHub:
github.com/appneta/node-traceview
We’re Hiring!