OPA for HTTP Authorization

Open Policy Agent[1] is a promising, light weight and very generic policy engine to govern authorization is any type of domain. I found this comparion[2] very attractive in evaluating OPA for a project I am currently working on, where they demonstrate how OPA can cater same functionality defined in RBAC, RBAC with Seperation of Duty, ABAC and XACML.  
Here are the steps to a brief demonstration of OPA used for HTTP API authorization based on the sample [3], taking it another level up.
Running OPA Server First we need to download OPA from [4], based on the operating system we are running on.  For linux, curl -L -o opa https://github.com/open-policy-agent/opa/releases/download/v0.10.3/opa_linux_amd64 Make it executable, chmod 755 ./opa Once done, we can start OPA policy engine as a server.
./opa run --server Define Data and Rules Next we need to load data and authorization rules to the server, so it can make decisions. OPA defines these in files in the format of .rego. Below is a sample …

Visualizing Code in Eclipse (Using Architexa)

I am here sharing a nice tool I recently found to draw the diagrams for my final year project at university. When the project is concerned, managing it is challenging with, 
  • code base of the project is pretty large
  • a team is working on the project
  • we need to maintain the quality and performance of the project 
  • proper documentation is also evaluated
So we were searching for an easy to use and nice looking tool to achieve the purposes without making it annoying that, we can focus more on the logic and optimization than decorating a diagram. :) That is were I found this plugin for eclipse called Architexa client, which is free for use.

Following is a sequence diagram I generated using the plugin, which didn't take more than 30s to draw than dragging the relevant classes and setting the relevant calls.

Following is a class diagram generated, that you can clearly observe the clear and smart look of the diagrams.


  1. From several tools that I have tried this was more faster and the diagram quality is great.
  2. It provides you the flexibility on deciding how the diagrams needs to be drawn, but to the rest on it's own.
  3. It provides sharing options with the tool that I am eager to try out.
  4. There several options to save and share the diagrams as images or files inside the project.
Rather than calling this cons, it is more suitable that I call them possible improvements that I haven't even seen them with any other freely available tool I tried.
  • This is little inconvenient to see generated members are not set in an orderly manner that always have to manually place them in order, as in following diagram.
Finally drawing diagrams has become fun, up-to date, truly useful and effective for code development for me. You can checkout whether it fits for you from here
I will share more experience with Architexa as I get more familiar. Cheers!


  1. Glad you find Architexa useful and thanks for the great post!

  2. Cool. Glad you also think Architexa is faster and results in better quality diagrams. We will definitely look into improving the automated diagram layout.


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