DEV Community: Mukesh Singh

Python

Mukesh Singh — Sat, 13 Sep 2025 19:49:16 +0000

What is a Python identifier?
A Python identifier is the name of a variable, function, class, module or object.

An identifier can start with a letter A-Z or a-z or an underscore.
An identifier can includes zero or more letter, number 0-9 and an underscore
Class name starts with uppercase letter and other letters are lower case
An identifier starts with a single underscore is used for private identifier
An identifier with two underscores is used for strongly private identifier
An identifer with prefix and suffix with two underscore indicates system identifier

Date Time Format in Python

Git

Mukesh Singh — Thu, 21 Aug 2025 12:49:15 +0000

git clone git@:

ssh-agent bash
Note if agent has not started it will throw error when running
ssh-add -l
Error connecting to agent: No such file or directory

Also it will ask for private key password

At the user folder
ssh-add ~/.ssh/

Test
ssh -Tv

git config user.email "YOUR_EMAIL"
git config user.name "YOUR_NAME"

Check remote URL

git remote -v

To Check Detail
git remote show origin

To change Origin

git remote set-url origin

Clean Architecture Vs Verticle Slice Achitecture

Mukesh Singh — Sat, 19 Jul 2025 18:04:13 +0000

Clean Architecture

Separation of concerns: Every layer has a specific responsibility and focus on single concern
Dependency rules Dependency flows inward. The high-level module should not aware of low-level module
Organises into layers
Business logic is decoupled from external concerns
Facilitates for more testing, automation testing and SOLID principles.
Provides flexibility and modular design to facilitate future flexibility

Vertical Skice Architecture

It emphasises end-to-end delivery, cutting layers by building small vertical features
_Creates feature-based folders
_It facilitates faster feedback, Team collaboration, and Incremental delivery.

References:
https://www.freecodecamp.org/news/a-quick-introduction-to-clean-architecture-990c014448d2/

Commonly used microservices design patterns

Mukesh Singh — Sun, 13 Jul 2025 18:16:42 +0000

Dedicated database for each service: A database dedicated to one service can’t be accessed by other services.
Saga pattern 2.1. Choreography: 2.2. Orchestration
API gateway pattern
Backends for Frontends pattern
Circuit breaker design pattern
pub-sub
Asynchronous messaging
Event sourcing
Strangler

Deploy Azure Function App using Terraform

Mukesh Singh — Sun, 13 Jul 2025 18:15:51 +0000

Azure Service Bus

Mukesh Singh — Sun, 13 Jul 2025 13:07:40 +0000

A queue with session enabled will guarantee the message stay in the order.
Azure Service Bus with session enabled automatically group messages into sessions.

Transaction in Service Bus:

Using a transaction group combines two or more operations together in execution scope. It is processed as a single unit. In transaction retry does not happen when any exception.

Send
Complete
Abandon
Deadletter
Defer
Renew lock

var options = new ServiceBusClientOptions { EnableCrossEntityTransactions = true };
await using var client = new ServiceBusClient(connectionString, options);

ServiceBusReceiver receiverA = client.CreateReceiver("queueA");
ServiceBusSender senderB = client.CreateSender("queueB");

ServiceBusReceivedMessage receivedMessage = await receiverA.ReceiveMessageAsync();

using (var ts = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled))
{
await receiverA.CompleteMessageAsync(receivedMessage);
await senderB.SendMessageAsync(new ServiceBusMessage());
ts.Complete();
}

Link

Message Session in Service Bus:

It allow joint and ordered procession of unbound sequence of related messages.

Session can be used FIFO and request-response pattern.

Sender can initiate a seesion when submitting message into topi with session-ID property. At AMQP 1.o it will be mapped to group-id property

Duplicate Detection in Service Bus:

When creating queue enable duplicate detection and set the detction window.

Partitioning in Service Bus:

A queue or topic is handled by a single message broker and stored in one messaging store.
A Service Bus enable queues and topics to be partitioned across multiple message brokers and message stores.

Topic Filters and Action in Service Bus:

## Filters
It's a rule consists of filter condition that selects particular message (e.g., SQL Filter, Boolean Filter, Correlation Filter)

## Action
It's a update statement. The action is done on the message after it has been matched and before message is selected into subscription.

adminClient = new ServiceBusAdministrationClient(connectionString);

// Create a SQL filter with color set to red
// Action is defined to set the quantity to half if the color is red
await adminClient.CreateRuleAsync(topicName, "ColorRed", new CreateRuleOptions
{
Name = "RedOrdersWithAction",
Filter = new SqlRuleFilter("user.color='red'"),
Action = new SqlRuleAction("SET quantity = quantity / 2;")
}

Transaction in Service Bus:

Patterns in Service Bus:

Broadcast Pattern
Partition Pattern
Routing Pattern

Service Bus

Azure Function App Authentication

Mukesh Singh — Sun, 13 Jul 2025 07:34:40 +0000

AuthorizationLevel

Anonymous
User
Function
System
Admin

Azure Function App

Mukesh Singh — Sat, 12 Jul 2025 23:00:08 +0000

Robust function characteristics

Avoid long-running functions
Plan cross-function communication
Write functions to be stateless
Write defensive functions
Security
Concurrency

Scaling

Event driven scaling
Concurrency in Function App Concurrency refers to the ability of a service to handle multiple requests or operations simultaneously. This can be achieved by
Parallelism Executing multiple tasks at the same time on different cpu/machine
Overlapping Execution Perform operation in a way that they dont block each other

Concurreny is achived by

-Thread pools
Assigning threads to handle incoming requests
-Async Operation
Async communication patterns to decouple tasks.
-Concurrency control mechanism

Pessimistic locking
Locking entire row to prevent users from modifying data that affects the current user
Optimistic Concurrency
Versioning
event driven architecture
Static Concurrency
Dynamic Concurrency

Fuction App Design Pattern

Database per Service - each service has its own private database
Shared database - services share a database
Saga - use sagas, which a sequences of local transactions, to maintain data consistency across services
Command-side replica - maintain a queryable replica of data in a service that implements a command
API Composition - implement queries by invoking the services that own the data and performing an in-memory join
CQRS - implement queries by maintaining one or more materialized views that can be efficiently queried
Domain event - publish an event whenever data changes
Event sourcing - persist aggregates as a sequence of events
Event based pattern In this way it can improve the speed, endurance and resilience of the process.
Async Pattern
With Async approachit eliminates blocking call

Consider async/await misuses anti patterns
Concurrency settings in host.json

"extensions": {
"http": {
"routePrefix": "api",
"maxOutstandingRequests": 200,
"maxConcurrentRequests": 100,
"dynamicThrottlesEnabled": true,
"hsts": {
"isEnabled": true,
"maxAge": "10"
},
"customHeaders": {
"X-Content-Type-Options": "nosniff"
}
}
}

Idempotent Design best practices

Verify input
Verify data freshness
Verify existence for update and delete operations
Duplicate detection
Concurrency control Link

Problem with Distributed Transaction

Problem with ACID

Saga Design Pattern

Optimistic Locking

Read the record and note the version. Use this version for writing the record

Pessimistic Locking

Apply exclusive lock until finished the operation

DEV Community: Mukesh Singh

Python

Git

Clean Architecture Vs Verticle Slice Achitecture

Clean Architecture

Vertical Skice Architecture

Commonly used microservices design patterns

Deploy Azure Function App using Terraform

Azure Service Bus

Transaction in Service Bus:

Message Session in Service Bus:

Duplicate Detection in Service Bus:

Partitioning in Service Bus:

Topic Filters and Action in Service Bus:

Transaction in Service Bus:

Transaction in Service Bus:

Patterns in Service Bus:

Service Bus

Azure Function App Authentication

AuthorizationLevel

Azure Function App

Robust function characteristics

Scaling

Concurreny is achived by

Fuction App Design Pattern

Consider async/await misuses anti patterns

Idempotent Design best practices

Problem with Distributed Transaction

Saga Design Pattern

Optimistic Locking

Pessimistic Locking