Blogs

I have been working with multiple teams on containerizing their infrastructure using docker. A while back I needed to help a team understand Docker containers by getting them to dive in and get started rather than just talk and point to slide decks. We started by containerizing the simplest possible .net core console app. The first app we built was a simple console app that used a timer and printed the date and time every 2 seconds. The code and the output for this program is below ...

The retry pattern is an extremely important pattern to make applications and services more resilient to transient failures. A transient failure is a common type of failure in a cloud-based distributed architecture. This is often due to the nature of the network itself (loss of connectivity, timeout on requests, and so on). Transient faults occur when services are hosted separately and communicate over the wire, most likely over a HTTP protocol. These faults are expected to be short-lived. Repeating such a request that has previously failed could succeed on a subsequent attempt. ...

Bulkhead Isolation pattern is used to make sure that all our services work independently of each other and failure in one will not create a failure in another service. Techniques such as single-responsibility pattern, asynchronous-communication pattern, Circuit Breaker and Retry pattern help achieve the goal of stopping a failure propagating throughout the whole application. To implement this pattern, all our services need to work independently of each other and failure in one should not create a failure in another service. We also need to partition the overall system into a few isolated groups, so that any failure in one partition does not percolate to others. Containerization and microservices are an option for having partitioned and isolated systems. ...

Representing dates in an API is a common but often not well thought out functionality.We need to be very cognizant of representing dates, intervals, and periods in the API Payload. There are two generally accepted date formats for API’s.

JSON Web Token(JWT) is an industry standard for security tokens used to securely transmit information between client and server as JSON objects.It provides a solution to the problem of passing claims between parties. In this post we will create an Angular interceptor to introspect JWT tokens.

Creating API’s has a certain rigor to it right from the design phase which is different from a UI based Web application. One of the areas where this is very apparent is communicating exceptions to the client. In a web application exception are communicated to the client using the UI with the most common being a 404 page. This page has been elevated to an art form now. The image below is a 404 page on Pixar’s website. ...

OpenID Connect is a simple identity layer built on top of the OAuth 2.0 protocol. OpenID Connect is all about authentication while OAuth is an authorization protocol. In OAuth, authorization is delegated while in OpenID Connect, authentication is delegated. OpenID Connect allows clients to verify end users based on the authentication performed by an auth server. It is also used to obtain basic profile information about the end user in a standards-based, interoperable and REST-like manner. OpenID Connect provides a standard way to obtain user identity.A central part of the OpenID Connect specification is the ID Token. It provides an identity token with information about the user. It also defines an endpoint to get identity information for that user, such as their name or e-mail address. This endpoint is called the user info endpoint. The identity token is a simple JWT token signed by the OpenID provider(OP) through OAuth protocol to suit web, mobile, and browser-based applications.The Identity token is encoded into the base 64 URL-safe string that contains information such as subject (sub), issuing authority (iss), audience (aud), and more. It may also contain some extra information about the user or custom claims in a set of scopes. As OpenID Connect is built on top of the Oauth2 protocol, the flows are the same. It can be used with the authorization code grant and the implicit grant. It’s not possible with the client credentials grant, as the client credentials grant is for server-to-server communication.As part of the oAuth flow, Instead of only requesting an access token, we can request an additional ID token from the security token service (STS) that implements the OpenID Connect specification. The client receives an ID token, and usually, also an access token. The ID token is kept small with the minimal information in it. To get more information for the authenticated user, the client can then send a request to the user info endpoint with the access token. This user info endpoint will then return the claims about the new user. ...

JSON Web Token(JWT) is an industry standard for security tokens used to securely transmit information between client and server as JSON objects.It provides a solution to the problem of passing claims between parties. In this post we will be implementing a JWT token server which will serve tokens to users with the appropriate credentials.

JSON Web Token(JWT) is an industry standard for security tokens used to securely transmit information between client and server as JSON objects.It provides a solution to the problem of passing claims between parties.

HTTP & HTTP/2 are both application level protocols that utilize a lower level protocol like TCP to talk on the Internet. The protocol of the Internet is TCP over IP over Ethernet.