Added howto for using header routing with Kubernetes

walkthroughs/howto-k8s-http-headers/.gitignore

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+_output

walkthroughs/howto-k8s-http-headers/README.md

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+## Overview
+This example shows how http routes can use headers for matching incoming requests.
+
+## Prerequisites
+[Walkthrough: App Mesh with EKS](../eks/)
+
+## Setup
+
+1. Clone this repository and navigate to the walkthrough/howto-k8s-cloudmap folder, all commands will be ran from this location
+2. **Your** account id:
+    ```
+    export AWS_ACCOUNT_ID=<your_account_id>
+    ```
+3. **Region** e.g. us-west-2
+    ```
+    export AWS_DEFAULT_REGION=us-west-2
+    ```
+4. **ENVOY_IMAGE** environment variable is set to App Mesh Envoy, see https://docs.aws.amazon.com/app-mesh/latest/userguide/envoy.html
+    ```
+    export ENVOY_IMAGE=...
+    ```
+5. Deploy
+    ```.
+    ./deploy.sh
+    ```

walkthroughs/howto-k8s-http-headers/colorapp/Dockerfile

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+FROM python:3
+
+COPY serve.py ./
+RUN chmod +x ./serve.py
+
+CMD ["python", "-u", "./serve.py"]

walkthroughs/howto-k8s-http-headers/colorapp/serve.py

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+#!/usr/bin/env python3
+
+try:
+    import os
+    from http.server import BaseHTTPRequestHandler, HTTPServer
+except Exception as e:
+    print(f'[ERROR] {e}')
+
+COLOR = os.environ.get('COLOR', 'no color!')
+print(f'COLOR is {COLOR}')
+
+PORT = int(os.environ.get('PORT', '8080'))
+print(f'PORT is {PORT}')
+
+class Handler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        if self.path == '/ping':
+            self.send_response(200)
+            self.end_headers()
+            return
+
+        self.send_response(200)
+        self.end_headers()
+        self.wfile.write(bytes(COLOR, 'utf8'))
+
+print('starting server...')
+httpd = HTTPServer(('', PORT), Handler)
+print('running server...')
+httpd.serve_forever()

walkthroughs/howto-k8s-http-headers/deploy.sh

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+#!/bin/bash
+
+set -e
+
+if [ -z $AWS_ACCOUNT_ID ]; then
+    echo "AWS_ACCOUNT_ID environment variable is not set."
+    exit 1
+fi
+
+if [ -z $AWS_DEFAULT_REGION ]; then
+    echo "AWS_DEFAULT_REGION environment variable is not set."
+    exit 1
+fi
+
+if [ -z $ENVOY_IMAGE ]; then
+    echo "ENVOY_IMAGE environment variable is not set to App Mesh Envoy, see https://docs.aws.amazon.com/app-mesh/latest/userguide/envoy.html"
+    exit 1
+fi
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
+PROJECT_NAME="howto-k8s-http-headers"
+APP_NAMESPACE=${PROJECT_NAME}
+MESH_NAME=${PROJECT_NAME}
+
+ECR_IMAGE_PREFIX="${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_DEFAULT_REGION}.amazonaws.com/${PROJECT_NAME}"
+FRONT_APP_IMAGE="${ECR_IMAGE_PREFIX}/feapp"
+COLOR_APP_IMAGE="${ECR_IMAGE_PREFIX}/colorapp"
+
+deploy_images() {
+    for app in colorapp feapp; do
+        aws ecr describe-repositories --repository-name $PROJECT_NAME/$app >/dev/null 2>&1 || aws ecr create-repository --repository-name $PROJECT_NAME/$app
+        docker build -t ${ECR_IMAGE_PREFIX}/${app} ${DIR}/${app}
+        $(aws ecr get-login --no-include-email)
+        docker push ${ECR_IMAGE_PREFIX}/${app}
+    done
+}
+
+deploy_app() {
+    EXAMPLES_OUT_DIR="${DIR}/_output/"
+    mkdir -p ${EXAMPLES_OUT_DIR}
+    eval "cat <<EOF
+$(<${DIR}/manifest.yaml.template)
+EOF
+" >${EXAMPLES_OUT_DIR}/manifest.yaml
+
+    kubectl apply -f ${EXAMPLES_OUT_DIR}/manifest.yaml
+}
+
+main() {
+    if [ -z $SKIP_IMAGES ]; then
+        echo "deploy images..."
+        deploy_images
+    fi
+
+    deploy_app
+}
+
+main

walkthroughs/howto-k8s-http-headers/feapp/Dockerfile

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+FROM python:3
+
+COPY serve.py ./
+RUN chmod +x ./serve.py
+
+CMD ["python", "-u", "./serve.py"]

walkthroughs/howto-k8s-http-headers/feapp/serve.py

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+#!/usr/bin/env python3
+
+try:
+    import os
+    import socket
+    from http.server import BaseHTTPRequestHandler, HTTPServer
+    from urllib.request import Request, urlopen
+    from urllib.error import URLError, HTTPError
+except Exception as e:
+    print(f'[ERROR] {e}')
+
+COLOR_HOST = os.environ.get('COLOR_HOST')
+print(f'COLOR_HOST is {COLOR_HOST}')
+
+PORT = int(os.environ.get('PORT', '8080'))
+print(f'PORT is {PORT}')
+
+class Handler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        if self.path == '/ping':
+            self.send_response(200)
+            self.end_headers()
+            return
+
+        try:
+            print('Trying to hit ' + COLOR_HOST.split(':')[0])
+            print(socket.gethostbyname(COLOR_HOST.split(':')[0]))
+            req = Request(f'http://{COLOR_HOST}')
+            cool_header = self.headers.get('color_header')
+            if cool_header is not None:
+                req.add_header('color_header', cool_header)
+            res = urlopen(req)
+            self.send_response(200)
+            self.end_headers()
+            self.wfile.write(res.read())
+
+        except HTTPError as e:
+            print(f'[ERROR] {e}')
+            self.send_error(e.code, e.reason)
+
+        except Exception as e:
+            print(f'[ERROR] {e}')
+            self.send_error(500, b'Something really bad happened')
+
+print('starting server...')
+httpd = HTTPServer(('', PORT), Handler)
+print('running server...')
+httpd.serve_forever()