DEV Community: Matthew Davis

The first Svelte 5 SPA router 🔥

Matthew Davis — Mon, 04 Nov 2024 06:35:45 +0000

An SPA router for Svelte that allows you to divide & conquer your app with nested routers, snippets, and more.

Live demo: https://svelte5-router.vercel.app

Features

Supports Svelte 5, just one rune baby 🚀!
Divide & conquer - use nested routers all over the place.
Use components, snippets, or both!
Use regex paths (e.g. /foo/(.*?)/bar) and/or named parameters together 🔥.
Use async routes simply with component: async () => import("./my-component.svelte").

Source code and more is at https://github.com/mateothegreat/svelte5-router.

Ambient Mesh with Istio like a boss!

Matthew Davis — Wed, 10 Jul 2024 17:59:14 +0000

Why ambient mesh and not sidecar?

Ambient mesh uses a shared agent on each Kubernetes node, called a ztunnel. This zero-trust tunnel securely connects and authenticates elements within the mesh, redirecting all traffic through the local ztunnel agent.

This separation allows operators to manage the data plane independently from applications, enabling easier scaling and upgrades.

Ztunnels provide core service mesh functions: zero trust, mTLS, telemetry, authentication, and L4 authorization, without parsing HTTP.

In comparison, ztunnel doesn't perform L7 processing, making it leaner than sidecars and suitable as shared infrastructure. The traditional sidecar, which has been a staple of Istio for years, now faces a significant competitor. This new contender challenges the long-standing dominance of the sidecar model, introducing innovative approaches and technologies that promise to enhance performance, security, and overall efficiency in service mesh architectures.

Pre-requisites

This post assumes you already have istio set up in ambient mode. In case you don’t, this will get you up and running in two minutes:

helm repo add istio https://istio-release.storage.googleapis.com/charts --force-update

helm install -n istio-system istio-base istio/base --create-namespace
helm install -n istio-system istio-cni istio/cni --set profile=ambient
helm install -n istio-system istiod istio/istiod --set profile=ambient
helm install -n istio-system ztunnel istio/ztunnel
helm install -n istio-ingress istio-ingress istio/gateway --create-namespace

kubectl get crd gateways.gateway.networking.k8s.io &> /dev/null || { kubectl kustomize "github.com/kubernetes-sigs/gateway-api/config/crd?ref=v1.1.0" | kubectl apply -f -; }

The `Gateway`

The Gateway API simplifies the configuration of ingress and egress traffic, providing a unified approach to managing traffic routing within the mesh. This helps in maintaining a clear and manageable structure for directing traffic to the appropriate services.

Setting Up the Gateway

To set up the Gateway, you need to create a Gateway resource that defines how traffic enters the mesh.

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: gateway
  namespace: ingress-internal
spec:
  gatewayClassName: istio
  addresses:          #
  - value: 10.0.16.3  # This block is optional
    type: IPAddress   #
  listeners:
  - name: http
    hostname: "*.matthewdavis.io"
    port: 80
    protocol: HTTP
    allowedRoutes:
      namespaces:
        from: Selector
        selector:
          matchLabels:
            gateway-internal-access: "true"
  - name: https
    hostname: "*.matthewdavis.io"
    port: 443
    protocol: HTTPS
    tls:
      mode: Terminate
      certificateRefs:
      - name: ingress-internal # Ensure secret is in the same namespace!
    allowedRoutes:
      namespaces:
        from: Selector
        selector:
          matchLabels:
            gateway-internal-access: "true"

Labeling the Namespace

💡 If you do not label your namespace(s) to match the selector above your routes will not be added!

Next, label the namespace that will host your internal services to allow the Gateway to route traffic to them. This is a crucial step which tells istio to look for HTTPRoute objects in this namespace.

kubectl label ns internal-services gateway-internal-access=true

Create `HTTPRoute` Objects

Create HTTPRoute resources to define how traffic should be routed to your services. Here’s an example for two different services:

Tool A

Define an HTTPRoute for tool-a:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: tool-a
  namespace: internal-services
spec:
  hostnames:
  - "tool-a.matthewdavis.io"
  parentRefs:
  - name: gateway
    namespace: ingress-internal
  rules:
  - backendRefs:
    - name: tool-a
      port: 8080

Tool B

Define an HTTPRoute for tool-b:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: tool-b
  namespace: internal-services
spec:
  hostnames:
  - "tool-b.matthewdavis.io"
  parentRefs:
  - name: gateway
    namespace: ingress-internal
  rules:
  - backendRefs:
    - name: tool-b
      port: 9090

Learn more

Angular Inter-Component Communication

Matthew Davis — Sun, 02 Feb 2020 07:10:28 +0000

Communicating between components can be a challenging concept to grasp. Fear not, I will show you how to effectively communicate between your components using a simple "service" design pattern.

At a high level the service class will hold our variables. When we want to access, or modify, these variables we will simply use dependency injection and "inject" our service class into the component class(es) that need to access this information.

Live Demo https://ng-byexamples-component-comms.herokuapp.com/

The Service

A service is nothing more than a class that contains reusable logic that you want to share between other services and components.

import { Injectable }  from '@angular/core';
import { FormControl } from '@angular/forms';

@Injectable({
    providedIn: 'root'
})
export class MyServiceService {

    /**
     * Holds the current page name.
     *
     * @type {string}
     */
    public currentPage: string;

    /**
     * Holds the value of the <input>'s.
     *
     * @type {number}
     */
    public someNumber: number = 0;

    /**
     * FormControl to hold the value of the <input> on each components page.
     * @type {FormControl}
     */
    public formControl: FormControl = new FormControl('');

    public constructor() {

        //
        // Subscribe to the formControl's changes and update the service value.
        //
        this.formControl.valueChanges.subscribe(value => this.someNumber = value);

    }

}

This is what the service class looks like based on the needs for this demo. You can add ass many properties as you want!

The Component

Our component will use dependency injection to inject our MyServiceService class instance and because we're making it public we can access it's properties and methods from within our template.

The Component Class

import { Component }        from '@angular/core';
import { MyServiceService } from '../my-service.service';

@Component({
    selector: 'app-page1',
    templateUrl: './page1.component.html',
    styleUrls: [ './page1.component.scss' ]
})
export class Page1Component {


    /**
     * By passing the service class to the constructor dependency injection
     * will automatically instantiate it for us.
     *
     * @param {MyServiceService} myServiceService class instance reference.
     */
    public constructor(public myServiceService: MyServiceService) {

    }

}

The Component Template

<h1>Page 1 Component</h1>

<p>Enter a value below and you will see it update in the footer!</p>

<label>Enter some Number:</label>
<input [formControl]="myServiceService.formControl">

As you can see by using [formControl]="myServiceService.formControl" we are binding the <input> attribute [formControl] to the FormControl instance from our service class.

NgByexamplesComponentCommunication

This project was generated with Angular CLI version 8.3.17.

Development server

Run ng serve for a dev server. Navigate to http://localhost:4200/. The app will automatically reload if you change any of the source files.

Code scaffolding

Build

Run ng build to build the project. The build artifacts will be stored in the dist/ directory. Use the --prod flag for a production build.

Running unit tests

Run ng test to execute the unit tests via Karma.

Running end-to-end tests

Run ng e2e to execute the end-to-end tests via Protractor.

Further help

To get more help on the Angular CLI use ng help or go check out the Angular CLI README.

View on GitHub

DEV Community: Matthew Davis

The first Svelte 5 SPA router 🔥

Features

Ambient Mesh with Istio like a boss!

Why ambient mesh and not sidecar?

Pre-requisites

The `Gateway`

Setting Up the Gateway

Labeling the Namespace

Create `HTTPRoute` Objects

Tool A

Tool B

Learn more

Angular Inter-Component Communication

The Service

The Component

The Component Class

The Component Template

See also

mateothegreat / ng-byexamples-component-communication

Communicate between components using a Service.

NgByexamplesComponentCommunication

Development server

Code scaffolding

Build

Running unit tests

Running end-to-end tests

Further help

DEV Community: Matthew Davis

The first Svelte 5 SPA router 🔥

Features

Ambient Mesh with Istio like a boss!

Why ambient mesh and not sidecar?

Pre-requisites

The Gateway

Setting Up the Gateway

Labeling the Namespace

Create HTTPRoute Objects

Tool A

Tool B

Learn more

Angular Inter-Component Communication

The Service

The Component

The Component Class

The Component Template

See also

mateothegreat / ng-byexamples-component-communication

Communicate between components using a Service.

NgByexamplesComponentCommunication

Development server

Code scaffolding

Build

Running unit tests

Running end-to-end tests

Further help

The `Gateway`

Create `HTTPRoute` Objects