Hello world sample for PHP (#15)

serving/samples/helloworld-php/Dockerfile

@@ -0,0 +1,6 @@
+FROM php:7.2.6-apache
+
+COPY index.php /var/www/html/
+
+# Run on port 8080 rather than 80
+RUN sed -i 's/80/8080/g' /etc/apache2/sites-available/000-default.conf /etc/apache2/ports.conf

serving/samples/helloworld-php/README.md

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+# Hello World - PHP
+
+A simple web app written in PHP that you can use for testing.application in PHP.
+It reads in an env variable `TARGET` and prints "Hello World: ${TARGET}". If
+TARGET is not specified, it will use "NOT SPECIFIED" as the TARGET.
+
+## Prerequisites
+
+* A Kubernetes Engine cluster with Knative installed. Follow the
+[installation instructions](https://github.com/knative/install/) if you need to create one.
+* The [Google Cloud SDK](https://cloud.google.com/sdk/docs/) is installed and initalized.
+* You have `kubectl` configured to connect to the Kubernetes cluster running Knative. If you created your cluster using the Google Cloud SDK, this has already be done. If you created your cluster from the Google Cloud Console, run the following command, replacing `CLUSTER_NAME` with the name of your cluster:
+
+    ```bash
+    gcloud containers clusters get-credentials CLUSTER_NAME
+    ```
+
+## Recreating the sample code
+
+While you can clone all of the code from this directory, hello world
+apps are generally more useful if you build them step-by-step. The 
+following instructions recreate the source files from this folder.
+
+1. Create a new directory and cd into it:
+    ````shell
+    mkdir app
+    cd app
+    ````
+1. Create a file named `index.php` and copy the code block below into it:
+
+    ```php
+    <?php
+      $target = getenv('TARGET', true) ?: "NOT SPECIFIED";
+      echo sprintf("Hello World: %s!\n", $target);
+    ?>
+    ```
+
+1. Create a file named `Dockerfile` and copy the code block below into it. 
+See [official PHP docker image](https://hub.docker.com/_/php/) for more details.
+
+    ```docker
+    FROM php:7.2.6-apache
+
+    COPY index.php /var/www/html/
+
+    # Run on port 8080 rather than 80
+    RUN sed -i 's/80/8080/g' /etc/apache2/sites-available/000-default.conf /etc/apache2/ports.conf
+    ```
+
+1. Create a file named `service.yaml` and copy the following service definition into the file. 
+Make sure to replace `{PROJECT_ID}` with the ID of your Google Cloud project. 
+If you are using docker or another container registry instead, replace the entire image path.
+
+    ```yaml
+    apiVersion: serving.knative.dev/v1alpha1
+    kind: Service
+    metadata:
+      name: helloworld-php
+      namespace: default
+    spec:
+      runLatest:
+        configuration:
+          revisionTemplate:
+            spec:
+              container:
+                image: gcr.io/{PROJECT_ID}/helloworld-php
+                env:
+                - name: TARGET
+                  value: "PHP Sample v1"
+    ```
+
+## Building and deploying the sample
+
+Once you have recreated the sample code files (or used the files in the sample folder) 
+you're ready to build and deploy the sample app.
+
+1. For this example, we'll use Google Cloud Container Builder to build the sample into a container. 
+To use container builder, execute the following gcloud command:
+
+    ```shell
+    gcloud container builds submit --tag gcr.io/${PROJECT_ID}/helloworld-php
+    ```
+
+1. After the build has completed, you can deploy the app into your cluster. 
+Ensure that the container image value in `service.yaml` matches the container
+you build in the previous step. Apply the configuration using kubectl:
+
+    ```shell
+    kubectl apply -f service.yaml
+    ```
+
+1. Now that your service is created, Knative will perform the following steps:
+   * Create a new immutable revision for this version of the app.
+   * Network programming to create a route, ingress, service, and load balance for your app.
+   * Automatically scale your pods up and down (including to zero active pods).
+
+1. To find the URL and IP address for your service, use kubectl to list the ingress points in the cluster:
+
+    ```shell
+    kubectl get ing
+
+    NAME                        HOSTS                                                                                   ADDRESS        PORTS     AGE
+    helloworld-php-ingress   helloworld-php.default.demo-domain.com,*.helloworld-php.default.demo-domain.com   35.232.134.1   80        1m
+    ```
+
+1. Now you can make a request to your app to see the result. Replace `{IP_ADDRESS}` 
+with the address you see returned in the previous step.
+
+    ```shell
+    curl -H "Host: helloworld-php.default.demo-domain.com" http://{IP_ADDRESS}
+    Hello World: PHP Sample v1!
+    ```
+
+## Removing the sample app deployment
+
+To remove the sample app from your cluster, delete the service record:
+
+```shell
+kubectl delete -f service.yaml
+```

serving/samples/helloworld-php/index.php

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+<?php
+  $target = getenv('TARGET', true) ?: "NOT SPECIFIED";
+  echo sprintf("Hello World: %s!\n", $target);
+?>

serving/samples/helloworld-php/service.yaml

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+apiVersion: serving.knative.dev/v1alpha1
+kind: Service
+metadata:
+  name: helloworld-php
+  namespace: default
+spec:
+  runLatest:
+    configuration:
+      revisionTemplate:
+        spec:
+          container:
+            image: gcr.io/{PROJECT_ID}/helloworld-php
+            env:
+            - name: TARGET
+              value: "PHP Sample v1"

serving/samples/helloworld-python/README.md

@@ -1,6 +1,6 @@
 # Hello World - Python sample
 
-This sample application shows how to create a hello world application in Python 3.
+This sample application shows how to create a hello world application in Python.
 When called, this application reads an env variable 'TARGET' 
 and prints "Hello World: ${TARGET}!".
 If TARGET is not specified, it will use "NOT SPECIFIED" as the TARGET.