Category Archives: microservices

Profiling a golang REST API server

go tool profiling

Profiling :

is a form of dynamic program analysis that measures, for example, the space (memory) or time complexity of a program, the usage of particular instructions, or the frequency and duration of function calls. Most commonly, profiling information serves to aid program optimization.

How can you profile your golang REST API server in a super simple way :

First : add some lines to your server code

import _ "net/http/pprof"

And then add a listener (I normally use a command line flag to trigger this) :

go func() {
http.ListenAndServe("localhost:6000", nil)

Start your server and generate some load. While your code is running under the load you generated extract the profiler data :

go tool pprof http://localhost:6000/debug/pprof/profile
Fetching profile over HTTP from http://localhost:6000/debug/pprof/profile
Saved profile in /home/paul/pprof/pprof.wm-server.samples.cpu.008.pb.gz
File: wm-server
Build ID: c806572b51954da99ceb779f6d7eee3600eae0fb
Type: cpu
Time: Dec 19, 2018 at 1:41pm (CET)
Duration: 30.13s, Total samples = 17.35s (57.58%)
Entering interactive mode (type "help" for commands, "o" for options)

You have many commands at this point but what I prefer to do, having used kcachegrind for years, is to fire it up using the kcachegrind command :

(pprof) kcachegrind

This will generate a callgrind formatted file and run kcachegrind on it to let you do all the usual analysis that you’re probably already used to do (call graph, callers, callees ..)


Microservices technology map

Microservices basic tools/technology quick guide (will always be work in progress)


REST API Server and Windows : ASP.NET Core kestrel, OWIN or plain old IIS + ASP.NET Framework ?

If you are planning to build API and make them available as micro services and your code assets are C#/.NET Framework/Windows then you have some choices :

  1. ASP.NET Core comes with an internal  web server called Kestrel : kestrel claims to be a light and fast web framework which runs ASP.NET Core applications without the need for IIS in front (you might decide that IIS is usefull for other things). Kestrel allows for middleware modules (like IIS ISAPI filters) that allow for adding features to the basic server.
  2. Katana (OWIN Microsoft implementation) is a collection of NuGET packages for building OWIN applications.
  3. Plain old IIS + ASP.NET REST API code

Some goo information can be found here from uShip guys
I’m basically writing this for myself as a reminder for the new .NET Core Microsoft environment.