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Deploy Capsule FaaS on OVH Cloud

For this recipe, I'm using an OVH Cloud compute instance (sponsored by @titimoby DevRel at OVH) with the following specifications:

  • Model: D2-4
  • RAM: 4 GB
  • Processor: 2 vCores

SSH Connect to the OVH Cloud compute instance

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ssh -i ./keys/capsule ubuntu@${OVH_IP}

Remark: I'm using a ssh key to connect to the OVH Cloud instance and OVH_IP is the IP address of the OVH Cloud instance.

Install the last version of Capsule HTTP on the OVH Cloud instance

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VERSION="v0.4.2" OS="linux" ARCH="amd64"
wget -O capsule-http https://github.com/bots-garden/capsule/releases/download/${VERSION}/capsule-http-${VERSION}-${OS}-${ARCH}

chmod +x capsule-http
sudo cp capsule-http  /usr/local/bin/capsule-http
rm capsule-http
capsule-http --version

If you already have Capsule HTTP installed and running, you need to stop it: 

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# from your computer
pkill capsule-http

Start Capsule HTTP on the OVH Cloud instance

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export CAPSULE_FAAS_TOKEN="ILOVEPANDAS"
nohup capsule-http --httpPort=8888 \
--faas=true \
--crt=faas.capsule.foundation.crt \
--key=faas.capsule.foundation.key &> /dev/null &
  • CAPSULE_FAAS_TOKEN allows to protect the admin routes
  • I have a domain name linked to the instance faas.capsule.foundation
  • --crt=faas.capsule.foundation.crt and --key=faas.capsule.foundation.key allow to use HTTPS.
  • --httpPort=8888, the port of the Capsule HTTP service.

To be able to connect on https://faas.capsule.foundation/, you need to do the following: 

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sudo iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-port 8888
sudo apt-get install iptables-persistent

Check the status of Capsule HTTP

If you open this URL https://faas.capsule.foundation/ on your browser, you should see the following message:

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Capsule [HTTP] v0.4.2 ⛱️ [beach umbrella]

Install the last version of CapsCtl

CapsCtl is a CLI to send commands to the Capsule HTTP server when it is running in FaaS mode.

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VERSION="v0.4.2" OS="linux" ARCH="arm64"
wget -O capsctl https://github.com/bots-garden/capsule/releases/download/${VERSION}/capsctl-${VERSION}-${OS}-${ARCH}
chmod +x capsctl
sudo cp capsctl  /usr/local/bin/capsctl
rm capsctl
capsctl --version

Add a start page to Capsule HTTP

We need to add a start page to Capsule HTTP by creating a new WASM function (module).

index.html

Create a file named index.html in a directory:

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<html>
  <head>
    <meta charset="utf-8">
    <title>Wasm is fantastic 😍</title>
      <meta name="viewport" content="width=device-width, initial-scale=1">
      <style>
        .container { min-height: 100vh; display: flex; justify-content: center; align-items: center; text-align: center; }
        .title { font-family: "Source Sans Pro", "Helvetica Neue", Arial, sans-serif; display: block; font-weight: 300; font-size: 80px; color: #35495e; letter-spacing: 1px; }
        .subtitle { font-family: "Source Sans Pro", "Helvetica Neue", Arial, sans-serif; font-weight: 300; font-size: 32px; color: #526488; word-spacing: 5px; padding-bottom: 15px; }
        .links { padding-top: 15px; }
      </style>
  </head>

  <body>
    <section class="container">
      <div>
        <h1 class="title">👋 Hello World 🌍</h1>
        <h2 class="subtitle">Served with 💜 by Capsule 💊 [HTTP] v0.4.2 ⛱️ [beach umbrella] </h2>
        <h2 class="subtitle">🎉 Hosted on OVH Cloud [🚀 Faas mode]</h2>
        <h2 class="subtitle">🥰 With the help of @titimoby</h2>
      </div>
    </section>
  </body>

</html>

main.go

Into the same directory, create a file named main.go and add the following code:

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go mod init index.page
touch main.go

main.go 

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// Package main => serving an html resource
package main

import (
    _ "embed"
    capsule "github.com/bots-garden/capsule-module-sdk"
)

var (
    //go:embed index.html
    html []byte
)

func main() {

    capsule.SetHandleHTTP(func (param capsule.HTTPRequest) (capsule.HTTPResponse, error) {

        return capsule.HTTPResponse{
            TextBody: string(html),
            Headers: `{
                "Content-Type": "text/html; charset=utf-8",
                "Cache-Control": "no-cache",
                "X-Powered-By": "capsule-module-sdk"
            }`,
            StatusCode: 200,
        }, nil
    })
}

Build the WASM module

Use the following command to build the WASM module: 

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go mod tidy
tinygo build -o index.page.wasm \
    -scheduler=none \
    --no-debug \
    -target wasi ./main.go

Deploy the WASM module on the OVH Cloud instance

From your computer, run the following command: 

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scp -i ./keys/capsule ./index-page/index.page.wasm ubuntu@${OVH_IP}:./

Start the index.page function

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export CAPSULE_FAAS_TOKEN="ILOVEPANDAS"
export CAPSULE_MAIN_PROCESS_URL="https://faas.capsule.foundation"

capsctl \
    --cmd=start \
    --name=index.page \
    --revision=default \
    --wasm=./index.page.wasm

You should get this output: 

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✅ index.page/default is started
ℹ️ url: https://faas.capsule.foundation/functions/index.page/default

Now you can call the function: 

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curl -X GET "https://faas.capsule.foundation/functions/index.page/default"

index.page function name is mapped to the / root

If you open this URL: https://faas.capsule.foundation in your browser, you will reach the index.page function.

It's a specific case of Capsule FaaS, and it's only possible because you name the function index.page when you started it with this command:

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capsctl \
    --cmd=start \
    --name=index.page \
    --revision=default \
    --wasm=./index.page.wasm

Create and Deploy a new function

main.go

Into the a directory, create a file named main.go and add the following code:

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go mod init hello
touch main.go

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package main

import (
    capsule "github.com/bots-garden/capsule-module-sdk"
)

func main() {
    capsule.SetHandleHTTP(func (param capsule.HTTPRequest) (capsule.HTTPResponse, error) {

        return capsule.HTTPResponse{
            TextBody: "🍊 👋 Hey " + param.Body +" !",
            Headers: `{"Content-Type": "text/plain; charset=utf-8"}`,
            StatusCode: 200,
        }, nil

    })
}

Build the WASM module

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tinygo build -o hello.wasm \
    -scheduler=none \
    --no-debug \
    -target wasi ./main.go

Deploy the WASM module on the OVH Cloud instance

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scp -i ./keys/capsule ./hello/hello.wasm ubuntu@${OVH_IP}:./

Start the hello function with a revision named orange

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capsctl \
    --cmd=start \
    --name=hello \
    --revision=orange \
    --wasm=./hello.wasm

You should get this output: 

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✅ hello/orange is started
ℹ️ url: https://faas.capsule.foundation/functions/hello/orange

Now you can call the function: 

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curl -X POST ${CAPSULE_MAIN_PROCESS_URL}/functions/hello/orange \
-H 'Content-Type: text/plain; charset=utf-8' \
-d 'Bob Morane'

You should get this output: 

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🍊 👋 Hey Bob Morane !