chore(kb): start evaluating dapr

.vscode/settings.json

@@ -134,6 +134,7 @@
         "cryptsetup",
         "csma",
         "daemonless",
+        "dapr",
         "datagram",
         "datasource",
         "datasources",

knowledge base/cloud computing/dapr.md

@@ -1,37 +1,51 @@
-# DAPR
-
-> TODO
+# Distributed APplication Runtime
 
 Portable, event-driven runtime for building distributed applications across cloud and edge.
 
-<!-- Remove this line to uncomment if used
-## Table of contents <!-- omit in toc -->
-
 1. [TL;DR](#tldr)
+1. [Self-hosted mode](#self-hosted-mode)
+1. [Clustered mode](#clustered-mode)
 1. [Further readings](#further-readings)
    1. [Sources](#sources)
 
 ## TL;DR
 
-<!-- Uncomment if used
+Codifies standards and best practices for building microservice applications into _building block_ APIs.<br/>
+Provides _cross-cutting_ APIs that apply across all the build blocks.<br/>
+Exposes its HTTP and gRPC APIs as a sidecar architecture to avoid requiring the application to include any Dapr-related
+runtime code.
+
+Building blocks:
+
+- Consist of an HTTP or gRPC API that can be called from one's code to use one or more Dapr components.
+- Enable building portable applications using the language and framework of one's choice.
+- Are independent from one another.
+- Have no limit to how many you use in one's application.
+
+Dapr can be executed:
+
+- [Self-hosted][self-hosted mode] on a Windows/Linux/macOS machine, e.g. for local development.
+- [Clustered][clustered mode] on Kubernetes or clusters of physical or virtual machines, e.g. for production.
+
 <details>
   <summary>Setup</summary>
 
 ```sh
+brew install 'dapr/tap/dapr-cli'
 ```
 
 </details>
--->
 
-<!-- Uncomment if used
 <details>
   <summary>Usage</summary>
 
 ```sh
+# Launch a sidecar for a blank application named 'myApp' that will listen on port '3500'.
+dapr run --app-id 'myApp' --dapr-http-port '3500'
+
 ```
 
 </details>
--->
 
 <!-- Uncomment if used
 <details>
@@ -43,6 +57,55 @@ Portable, event-driven runtime for building distributed applications across clou
 </details>
 -->
 
+## Self-hosted mode
+
+Dapr runs as a separate sidecar process **for each** service.<br/>
+This sidecar can be called via HTTP or gRPC to use state stores, pub/sub, binding components, and the other building
+blocks.
+
+Use the Dapr CLI to run Dapr-enabled applications on one's local machine.
+
+```sh
+brew install 'dapr/tap/dapr-cli'
+dapr init
+```
+
+This:
+
+- Fetches and installs the Dapr sidecar binaries locally.
+- Creates a development environment to streamline application development with Dapr.
+
+The development environment includes:
+
+- Running a Redis container as a local state store and message broker.
+- Running a Zipkin container for observability.
+- Creating a default components folder with component definitions for the above.
+- Running a Dapr placement service container for local actor support.
+- Running a Dapr scheduler service container for job scheduling.
+
+## Clustered mode
+
+<details>
+  <summary>In Kubernetes</summary>
+
+Dapr runs as a sidecar container alongside the application container in the same pod by using the
+`dapr-sidecar-injector` and `dapr-operator` control plane services.
+
+The `dapr-sentry` service acts as a certificate authority to enable mutual TLS between Dapr sidecar instances.<br/>
+This provides secure data encryption as well as providing identity via [Spiffe].
+
+</details>
+
+<details>
+  <summary>On clusters of machines</summary>
+
+Dapr's control plane services can be deployed in high availability mode to machines.
+
+Dapr uses multicast DNS by default to provide name resolution via DNS for the applications running in the cluster.<br/>
+This can be optionally replaced by Hashicorp's Consul.
+
+</details>
+
 ## Further readings
 
 - [Website]
@@ -58,7 +121,12 @@ Portable, event-driven runtime for building distributed applications across clou
   -->
 
 <!-- In-article sections -->
+[clustered mode]: #clustered-mode
+[self-hosted mode]: #self-hosted-mode
+
 <!-- Knowledge base -->
+[spiffe]: ../spiffe.md
+
 <!-- Files -->
 <!-- Upstream -->
 [codebase]: https://github.com/dapr/dapr