As part of development using hasura , we would develop a set of graphql apis using database models . Hasura models will be available as set of migration scripts and metadata file . As requirements keep on adding ( or rather changing ) , there would be further migration scripts generated and metadata changes . As developer , you would get worried about the quality of migration scripts . Main cause of worry will be that of regression .

  • With every each change , are some of the queries failing which consumers have written . …


Hasura makes it super easy to scaffold a inquiry or mutation given a database model . In first part we looked at how hasura makes it easy to develop a small leave maintenance application with minimum coding effort . We just need to do a design for database modelling and most of our backend code is ready , voila 🔅 . Refer to first part over here .

However aEnterprise application requires more than simply inserting into a database model . Data validation is super critical . It would be important to check input data for correctness else database will…


Leave application using Hasura and Vue

As application development engineer , it feels good when you can develop a web application end to end . That means controlling the complete front to back experience .

As developer , would like a framework and tools , which makes it easy to write business logic and allow application developer to treat framework as black box and not getting into internals of framework too much ( not at the start at least)

I also have to admit that , developing a front end is not my professional competence . …

elastic search — searching simplified


Assume you have customer information system or customer on-boarding system . Most important functionality would be searching .

  • on-boarding system would like to understand whether there is existing customer by the same name .
  • Customer information search system would like to search by name

Article shows how elastic search makes searching easier . Article cover some of interesting features of elastic search

  • Searching documents ( made of texts ) with any order of the input words ( a.k.a Full text search) .
  • searching documents with small variation of spelling to that of input ( a.k.a edit distance search)
  • Searching documents…

face recognition has become a very important tool . Many interesting use cases have come up which uses for face recognition . One interesting use case , is that Chinese government is using face recognition to catch criminals .

Another use case , i encountered on the twitter . Face recognition was used to display departure gate details to airport travelers . Airport is Chengdu Shuangliu International Airport in china . Seems pretty amazing feat of technology.

face recognition using passport photo

Question is how do you use face recognition in application software . Approach can depends on the number…

Let us consider a typical authentication and authorization scenario for api

  • User passes id/password to the server as part of authentication .
  • password is validated , server generates a token and saves the token in the database against the user id.
  • Server sends a token to the client.
  • Client will send the token back in all subsequent api request .
  • Server will validate the token against the one saved in the database and allow the request to proceed ,provided user has correct authorization on the api .
Authorization issues in case of micro services communication

In micro services architecture , services communicate to each other by using api…

Adoption of micro services architectures bring agility into the software development.It allows for a faster feature development . Each micro service is small enough to be developed and maintained by couple of software developers . The small footprint also allows for faster boot up and shut down times. Adoption of micro services results into new sets of challenges. One of the challenge would be of a communication between micro services .

Communication between micro services .

  • api based communication
  • event based communication

In api based communication pattern , micro services communicate with each other by using api end points …

ionic framework is one of the popular framework for creating mobile apps. Most frequently used command lines as reference .

Creating a blank application

ionic start Loyalty blank — V2 .

This command creates a new blank ionic application with home page.

Adding a new page into application

During application development , we create master detail pattern . Master page would be home page and detail page , we would add as we evolve our application .

ionic g page earnpoints

here page name is earnpoints .Ionic framework will create a folder earnpoints and create earnpoints.ts and earnpoints.html .It …

While working on Unix and Linux . we need to create a patch or a local change . this patch change is compiled and built into shared object .

when we run our services , however there is always doubt , whether code change has been really picked up by running service . Many of times , we resort to put printfs(debugs ) into the code and run again .

Our shared object ,could be lying in multiple paths ,due to which it is possible that , exact location from which shared object is loaded may not be known.



Interests : software design ,architecture , search, open banking , machine learning ,mobility

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