Author: sandeeppote

Kubernetes commands for managing Pods

To get the cluster info use-

kubectl cluster-info

To get list of nodes user-

kubectl get nodes

Creating Pod – imperative way

Create a POD with nginx image and name nginx in default namespace

// kubectl run <<pod name>> --image <<image in docker hub>> 
kubectl run nginx --image nginx

Create a POD with nginx image and name nginx in different namespace

// kubectl run <<pod name>> --image <<image in docker hub>> -n <<namespace name>>
kubectl run nginx --image nginx -n production

Get Pods and details

Get a list of POD’s in default namespace

kubectl get pods

Get a list of POD’s in other namespace

//kubectl get pods -n <<namespace name>>
kubectl get pods -n production

Check the node of the Pod it is created-

kubectl get pods -o wide

Create POD using yaml – declarative way

// file name- pod-definition.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod-yaml
spec:
  containers:
    - name: nginx-container-yaml
      image: nginx

Create a pod declarative way-

kubectl create -f pod-definition.yaml

Deleting Pod

Delete a pod in default namespace

// kubectl delete pod <<pod-name>>
kubectl delete pod nginx-pod-yaml

Delete all pods in default namespace

kubectl delete --all pods

Delete a pod in custom namespace

//kubectl delete pod <<pod-name>> -n <<namespace-name>>
kubectl delete pod nginx-pod-yaml -n development

Delete all pods in custom namespace

//kubectl delete --all pods -n <<namespace-name>>
kubectl delete --all pods -n development

Create a Asp.Net simple rendering using data source in Helix Examples Solution

In this blog will create a simple rendering uing Asp.Net Rendering SDK in Helix Examples Solution

Please refer the blog to create a rendering folder and configure the SCS before proceeding this blog.

So lets create a new module or rendering feature named “Articles”.

1. Create a Feature project using Razor Class Library

Project Name – BasicCompany.Feature.Articles.Rendering

Notice the project path

Choose .Net Core 3.1 Framework-

Delete any exisitng files and folders under this project-

Edit the project to use netcoreapp3.1 and AddRazorSupportForMvc to true

Rename helix-basic-aspnetcore\src\Feature\Articles\BasicCompany.Feature.Articles.Rendering to rendering. Just to follow other feature fodler structure.

2. Install Sitecore packages

Sitecore.AspNet.RenderingEngine

Sitecore.LayoutService.Client

I have installed verions 16 just to be in sync with other projects. You may install the latest.

New rendering project should have these packages installed-

Remove these packages as this may be not required at thi point of time or downgrade this to 3.1.1

Refer the new created rendering project to BasicCompany.Project.BasicCompany.Rendering

When the solution is build you may see this error-

Severity Code Description Project File Line Suppression State
Error The package reference ‘Sitecore.AspNet.RenderingEngine’ should not specify a version. Please specify the version in ‘C:\projects\Helix.Examples\examples\helix-basic-aspnetcore\Packages.props’ or set VersionOverride to override the centrally defined version. BasicCompany.Feature.Articles.Rendering C:\projects\Helix.Examples\examples\helix-basic-aspnetcore\src\Feature\Articles\rendering\BasicCompany.Feature.Articles.Rendering.csproj

Solution– Remove the version for the plugin fropm project file

Edit the project file and remove version from the PackageReference-

Solution should build successully.

3. Ensure Articles.modules.json file in Feature folder

Please see this blog <<Enter blog url here>> how to create a module.json file to serliaze the Sitecore items for new Feature.

4. Create required Sitecore Templates, content, renderings and Placeholder Settings

Template – Article in following path- /sitecore/templates/Feature/Articles

Page Type Template – Create 2 page type templates “Articles” and “Article” page as below.

Add any required Insert Options where necessary.

IMP- inherit from _NavigationItem to display the Articles as Navigation option

Enter Navigation Title for Articles page-

Content

Create content in Home page based on the Article templates created.

Rendering

Create a new Json Rendering Article. See previous post

Set Datasource Location- ./Page Components|query:./ancestor-or-self::*[@@templatename=’Site’]/Shared Content/Articles

Datasource Template- /sitecore/templates/Feature/Articles/Article

Add rendering to Template

Add Header, Article and Footer Controls to the Presentation

Select appropriate datasource for the Article component-

You can also add the component from experience editor. For simplicity purpose I am adding this from the presentation details manually.

Publish the changes and see https://www.basic-company-aspnetcore.localhost

Note:- If you get bad gateway error the resolution is in this blog <<blog for resolution>>

you should see the Articles option in Navigation-

Note- We wont be configuring “Articles” page in this blog. Will see that in next blog when uing Content Resolver.

See thie Article page-

https://www.basic-company-aspnetcore.localhost/Articles/Sitecore%20Content%20Serialization%20structural%20overview

There is a error – “Unknown component ‘Article'”. This is because we havent yet created view for this component.

Create Model in BasicCompany.Feature.Articles.Rendering project for rendering Article component

Note the propeties are using Sitecore.LayoutService.Client.Response.Model.Fields

using Sitecore.LayoutService.Client.Response.Model.Fields;
using System;
using System.Collections.Generic;
using System.Text;

namespace BasicCompany.Feature.Articles.Rendering.Models
{
    public class Article
    {
        public TextField Title { get; set; }

        public RichTextField Description { get; set; }

        public TextField ShortDescription { get; set; }
    }
}

Create View in BasicCompany.Feature.Articles.Rendering project for rendering Article component

Create Article.cshtml file under Views/Shared/Components/SitecoreComponent

Add following markup-


@model Article

<div class="container">
    <section class="hero is-small product-detail-hero">
        <div class="hero-body">
             <h3  class="title" asp-for="Title"></h3>
            <sc-text class="subtitle is-one-quarter" asp-for="Description"></sc-text>
        </div>
    </section>
</div>

InViews Folder create _ViewImports.cshtml file and put the following in file-

@using Sitecore.LayoutService.Client.Response.Model
@using Sitecore.LayoutService.Client.Response.Model.Fields
@using Sitecore.AspNet.RenderingEngine.Extensions
@using BasicCompany.Feature.Articles.Rendering.Models

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
@addTagHelper *, Sitecore.AspNet.RenderingEngine

Add Extensions for registering the ModelBoundView. This is a static class and will be used in Project Rendering on application startup (BasicCompany.Project.BasicCompany.Rendering).

using BasicCompany.Feature.Articles.Rendering.Models;
using Sitecore.AspNet.RenderingEngine.Configuration;
using Sitecore.AspNet.RenderingEngine.Extensions;

namespace BasicCompany.Feature.Articles.Extensions
{
    public  static class RenderingEngineOptionsExtensions
    {
        public static RenderingEngineOptions AddFeatureArticle(this RenderingEngineOptions options)
        {
            options
                .AddModelBoundView<Article>("Article");            
            return options;
        }
    }
}

In BasicCompany.Project.BasicCompany.Rendering project, Startup.cs register the component-

Build the Project

Output– https://www.basic-company-aspnetcore.localhost/Articles/Sitecore%20Content%20Serialization%20structural%20overview

Issues

Bad gateway error while accessing – https://www.basic-company-aspnetcore.localhost/

Solution-

Restart the rendering container

docker ps
docker restart <<rebdering container>>

Debug Helix Examples solution using Asp.Net Rendering hosted in Docker Containers

See this blog to setup the development environment for Helix Examlpes using Docker

Open the solution from following location – \examples\helix-basic-aspnetcore

Open the containers tab and should list all the containsers with its status-

You may also use following command to check the status of contrianers-

docker ps

Lets debug the Navigation which has content resolver-

Right click the CD container and Attach to Process

Select Managed(.Net 4.x) debug type. Select w3wp.exe and click Attach.

Helix Examples Solution should now run in debug mode.

Build the solution, add a breakpoint to any of the resolvers (Header or Footer)

Refresh or visit the site – https://www.basic-company-aspnetcore.localhost/ and should be able to see the debugger-

Issues debuging or just building the solution-

Bad Gateway-

Solution- You may see the errors with command-

docker-compose logs -f rendering

Following log appears- binary is being used by another process. This is the issues with the dotnet watch with the docker

Solution- Restart the rendering container

This should bring up the site.

You can also watch the changes outside the docker. See here for more details-

https://sitecore.stackexchange.com/questions/29566/asp-net-core-rendering-sdk-every-time-i-have-to-run-docker-compose-restart-ren

Sitecore Headless Development with ASP.NET Rendering SDK – Helix Examples Solution – The Docker Way

This blog will give a quick overview of setting development environment for Headless Development with ASP.Net Rendering SDK using the Helix Examples and the docker.

Although there are videos and blogs around same I will do a quick walk through on setting Helix Examples and any errors I faced whilst setting up the environment.

Refer the following for same – https://github.com/Sitecore/Helix.Examples/tree/master/examples/helix-basic-aspnetcore

Install .Net Core 3.1

https://dotnet.microsoft.com/en-us/download/dotnet/3.1

Install .Net core 3.1 on your machine and this is required to create any rendering or platform projects later to extend the Helix Examples Solution or compiling the existing code.

Install Docker Desktop on Windows

https://docs.docker.com/desktop/windows/install/

Run this on Hyper-V mode and Switch to Windows Containers

Install Visual Studio Code and Visual Studio 2022 Community Edition

https://visualstudio.microsoft.com/vs/community/

https://code.visualstudio.com/download

Whilst installing Visual Studio 2022 select the .Net Framework project and templates option as the platform projects uses .Net Framework 4.8 version. This will also help further if you want to extend the solution.

Install and Configure Windows Terminal (optional)

https://docs.microsoft.com/en-us/windows/terminal/install

https://dev.to/shahinalam02/customize-your-terminal-using-oh-my-posh-theme-38if

https://www.hanselman.com/blog/my-ultimate-powershell-prompt-with-oh-my-posh-and-the-windows-terminal

Install Windows Terminal, refer above link and if you fancy applying the themes, although this is optional.

Install git

https://git-scm.com/download/win

Clone Helix Examples Solution

https://github.com/Sitecore/Helix.Examples

https://github.com/Sitecore/Helix.Examples.git

Initialise the config

Navigate to \examples\helix-basic-aspnetcore and run following-

.\init.ps1 -LicenseXmlPath C:\<<path to license>>\license.xml -SitecoreAdminPassword "b"

This should initalise teh .env file and fill in the values of the variables for License and Admin Password. Also it will populate other variables.

Build Images

Once the config are initialised run folowing command-

up.ps1

Once all the images are downloaded and built along with solution login to CM should will be asked.

Login to the CM and Allow access to Sitecore API and Offline Access

Once this done the CD and CM app should be ready along with the data been synched.

Check the logs for any errors in rendering with following command-

docker-compose logs -f rendering

Access Application

Site can be accessed with the following url –

Sitecore Content Management: https://cm.basic-company-aspnetcore.localhost/sitecore/

Sitecore Identity Server: https://id.basic-company-aspnetcore.localhost

Basic Company site: https://www.basic-company-aspnetcore.localhost

Use following to stop/remove containers-

docker compose down

Issues while building the images

Error response from daemon: Unrecognised volume spec: file ‘\\.\pipe\docker_engine’ cannot be mapped. Only directories can be mapped on this platform

Solution-

Disable Docker Compose V2 using command or in Docker Desktop-

docker-compose disable-v2

or Uncheck the “Use Docker Compose V2” option

https://stackoverflow.com/questions/68010612/error-response-from-daemon-unrecognised-volume-spec-file-pipe-docker-engi

Solidity deployment error – ContractNotFound: No contract deployed at address

At time when the Ganache tool is re-opened all the Transactions and Constracts are reset. Whilst deploying contract you might see the error –

ContractNotFound: No contract deployed at {address}

PS C:\Projects\Blockchain\Solidity\brownie_fundme> brownie run .\scripts\deploy.py --network ganache-local
INFO: Could not find files for the given pattern(s).
Brownie v1.19.0 - Python development framework for Ethereum

BrownieFundmeProject is the active project.
  File "C:\Users\sandeep\.local\pipx\venvs\eth-brownie\lib\site-packages\brownie\_cli\__main__.py", line 64, in main
    importlib.import_module(f"brownie._cli.{cmd}").main()
  File "C:\Users\sandeep\.local\pipx\venvs\eth-brownie\lib\site-packages\brownie\_cli\run.py", line 45, in main
    network.connect(CONFIG.argv["network"])
  File "C:\Users\sandeep\.local\pipx\venvs\eth-brownie\lib\site-packages\brownie\network\main.py", line 55, in connect
    p._load_deployments()
  File "C:\Users\sandeep\.local\pipx\venvs\eth-brownie\lib\site-packages\brownie\project\main.py", line 370, in _load_deployments
    contract = ProjectContract(self, build, build_json.stem)
  File "C:\Users\sandeep\.local\pipx\venvs\eth-brownie\lib\site-packages\brownie\network\contract.py", line 1305, in __init__
    _DeployedContractBase.__init__(self, address, owner, tx)
  File "C:\Users\sandeep\.local\pipx\venvs\eth-brownie\lib\site-packages\brownie\network\contract.py", line 708, in __init__
    raise ContractNotFound(f"No contract deployed at {address}")
ContractNotFound: No contract deployed at 0x7465E5ca8aFeFba39eFD83bd056ACAafa3d16646

Solution-

Delete all the files and folders in Deployment folder as closing the Ganache tool will reset contracts etc. the deployment folder has references to old contract.

Reference-

https://stackoverflow.com/questions/68460396/contractnotfound-no-contract-deployed-at

Add new network in Ganache using brownie for Ethereum Smart Contract local development

This should show the list of networks available in Brownie.

brownie networks list

In the Ethereum (persistent network) there is no Ganache(local) network

Add a network to Ethereum

brownie networks add Ethereum ganache-local host=http://127.0.0.1:7545 chainid=1337

Name of the network- ganache-local

host- where ganache endpoint is listening i.e. RPC Server

chainid – for ganache it is 1337

Output

Install Ganache for Solidity development

Ganache is the development tool used to run local blockchain for Ethereum development.

Ganache can be used to deploy the contract to local Blockchain. Its a simutated environemnt like Javascript VM when developing on Remix. It helps spin up a local Blockchain.

Ganache UI

Install the Ganache from following location-

https://trufflesuite.com/ganache/

Click the QUICKSTART to get started with Ethereum. By default Ethereum is selected. Ganache can also be used for Corda development

The next screen shows the local Blockchain with the Accounts having 100 ETH and ready to receive the contracts and transactions.

Options in Ganache in later post.

Ganache CLI-

Similar to Ganache UI the local Blockchain node can be setup using CLI.

Install nodejs – https://nodejs.org/en/download/

Check the version of node js

node -v

Install yarn

npm install --global yarn

Install Ganache CLI

yarn global add ganache-cli

Verify installation by checking the version

ganache-cli --version
Ganache CLI v6.12.2 (ganache-core: 2.13.2)

Use following command to see the Accounts, Transactions, Contracts etc in command line same as UI.

ganache-cli --deterministic

For more CLI options see –

https://www.npmjs.com/package/ganache-cli

Start deploying Contracts, signing and sending transactions to the local Blockchain.

To use Blockchain as a service use-

https://infura.io/

https://www.alchemy.com/

Blockchain Concepts

Advantages of Blockchain-

  • Decentralised – Having no single point of authority
  • Transperancy and Flexibility
  • Speed and Effeciency
  • Security and Immutability
  • Removal of counterparty risk
  • Trust minimised agreements
  • Hybrid smart conrtract with Chain Link (Oracle)

Terms and Abbrevations used in Blockchain-

DAO’s – Decentralised Autonomous Organization’s

Testnet – are free and for testing smart contracts

Mainnet – cost money and are considered “live”

Faucet – is and application that gives us free test token, like free test Rinkeby Ethereum

Block Explorer – an application that allows us to “view” transactions that happen on a blockchain.

Gas – is a unit of computational measure. The more computation a transaction uses the more “gas” you have to pay for.

Every transaction that happens on-chain pays a “gas fee” to node operators.

The amount of “gas” used and how much you pay depends on how “computationally expensive” your transaction is.

Sending ETH to 1 address would be “cheaper” than sending ETH to 1,000 addresses.

Gwei (giga-wei) – denomination or a small unit of Ether 1 Ether is 1 billion Gwei. It is used to measure cost of transaction i.e. used in the Ethereum network to but and sell goods and services.

Gas – Measure of computation use

Gas Price – How much it costs per unit of gas.

Gas Limit – Max amount of gas in a transaction

Transaction Fee – Gas used X Gas Price i.e. 21,000 gas @ 1GWEI per gas =21,000 GWEI

Gas Price of Ehtereum fluctuates based on the demand of the blockchain. More perople using or want to make transactions, the higher the gas price and therefore the higher the transaction fees.

Gnesis Block – First block in a blockchain

Hash – Unique fixed length string to identify a piece of data

Hash Algorithm – A function or algorithm that computes data into a unique hash.

Mining – The precess of finding the “solution” to the blockchain “problem”. Node get paid for mining blocks.

Block – A list of transactions mined together

Nonce – A “number used once” to find the “solution” to the blockchain problem. It’s also used to define the transaction number for an account/address.

Public Key – Is derived from your private key. Anyone can “see” it, and user it, and user it to verify that a transaction came from you.

Private key – Only know to the keyholder, its used to “sign” transactions.

Elliptic Curve Digital Signature Algorithm (ECDSA) – generates public key using private key.

Signing Transactions – A “one way” process. Someone with a private key signs a transaction by their private key being hashed with their transaction data. Anyone can then verify this new transaction hash with your public key.

Node: Single instance in a decentralized network. Anyone can join the network. Blockchains are resilient. Blockchain nodes keep lists of the transactions that occur. They are immutable- nothing can corrupt them.

Consensus – is the mechanism used to agree on the state of a blockchain.

Broken into 2 :-

— Chain Selection

Sybil Resistance – Proof of work. Block Author, defends on fake blockchains

— — PoW – Minners. Uses lot of electricity and is hence costly.

-Transaction Fees and Block Reward.- compete each other to find the answer to the problems. Whoever finds first get the transaction fees.

Sybil Attack – creates fake accounts to influence the network

51% attack

Longest Chain Rule

– — PoS — Validators – nodes put up collateral as a sybil resistance mechanism. Uses less energy. Slightly less decentralised.

ABI– ApplicationBinary Interface- tells Solidity how it can interact with another contract. What functions can be called from the contract. Interfaces compile down to ABI.

Python – Metaclass

In Python, metclass is a class whose instances are classes. Metaclass are derived from type.

Metaclasses change the classes automatically when decorators are not efficient use metaclass.

Metaclass implements __new__ method which calls the parent class to create a new instance. The creation of metaclass includes the name of the class, class bases and attributes used in the class.

Metaclass are used to create class dyunamically using the type keyword. See following code snippet-

car = type("vehicle", "Vehicle", "{speed:50}")

Here the type accepts the name of the instance, then the baseclass name and attributes defined for the object.

See the below code to create your own metaclass.

Vehicle_Meta class inherits from type. Implements __new__ method which accepts four parameters. cls, name – name of the class to be dynamically created, bases – meta class base class and dict- attributes attached to the class. custom attribute speed is created.

Vehicle class refers to the meta class Vehicle_Meta.

When the __dict__ is accessed it has the custom attribute along with other attributes created as a part of Class.