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Internal and external load balancer from one K8s Service

Using Google Cloud, deploy a sample application to Google Kubernetes Engine (GKE), and expose it both on a public IP address using a regional external Application Load Balancer, and on a private IP address using an internal passthrough Network Load Balancer.

The two load balancers use different

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#!/bin/sh
go build -o /layers/google.go.build/bin/main ./. && /layers/google.go.build/bin/main

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apiVersion: example.com/v1
kind: DigesterFunction
metadata:
  name: digester
  annotations:
    config.kubernetes.io/function: |
      exec:
        path: ./digester

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# Docker Desktop not required
brew install docker hyperkit minikube
minikube start --driver=hyperkit
# or persistent: minikube config set driver hyperkit
eval $(minikube docker-env)
# docker build/run away

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#!/usr/bin/env bash
#
# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#

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# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,

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#!/usr/bin/env bash
#
# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#

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WSGI middleware can be used to validate incoming requests for APIs implemented in Python.

See middleware.py below for an example that validates the presence of a content key in the JSON body of an incoming HTTP POST request.

appengine_config.py shows how to add this middleware to an application running in Google App Engine Python Standard Environment.

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Install Knative using Minikube on macOS

This will install Istio 0.8.0 and Knative 0.1.0 on a Minikube cluster running Kubernetes 1.10.6, and then deploy a sample application.

Install prerequisites

Install kubectl (https://kubernetes.io/docs/tasks/tools/install-kubectl/#install-with-homebrew-on-macos):

brew install kubernetes-cli

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import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;

public class PairPermutations {

  public static void main(String[] args) {
    Iterator<String> itemsIterator = Arrays.asList("1", "2", "3").iterator();