feature: move mysql operator to this repo

sample-operators/mysql-schema/README.md

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+# MySQL Schema Operator
+
+This example shows how an operator can control resources outside of the Kubernetes cluster. In this case it will be
+managing MySQL schemas in an existing database server. This is a common scenario in many organizations where developers
+need to create schemas for different applications and environments, but the database server itself is managed by a 
+different team. Using this operator a dev team can create a CR in their namespace and have a schema provisioned automatically.
+Access to the MySQL server is configured in the configuration of the operator, so admin access is restricted. 
+
+This is an example input:
+```yaml
+apiVersion: "mysql.sample.javaoperatorsdk/v1"
+kind: MySQLSchema
+metadata:
+  name: mydb
+spec:
+  encoding: utf8
+```
+
+Creating this custom resource will prompt the operator to create a schema named `mydb` in the MySQL server and update
+the resource status with its URL. Once the resource is deleted, the operator will delete the schema. Obviously don't
+use it as is with real databases. 
+
+### Try 
+
+To try how the operator works you will need the following:
+* JDK installed (minimum version 11, tested with 11 and 15)
+* Maven installed (tested with 3.6.3)
+* A working Kubernetes cluster (tested with v1.15.9-gke.24)
+* kubectl installed (tested with v1.15.5)
+* Docker installed (tested with 19.03.8)
+* Container image registry
+
+How to configure all the above depends heavily on where your Kubernetes cluster is hosted. 
+If you use [minikube](https://minikube.sigs.k8s.io/docs/) you will need to configure kubectl and docker differently
+than if you'd use [GKE](https://cloud.google.com/kubernetes-engine/). You will have to read the documentation of your
+Kubernetes provider to figure this out.
+
+Once you have the basics you can build and deploy the operator.
+
+### Build & Deploy
+
+1. We will be building the Docker image from the source code using Maven, so we have to configure the Docker registry
+where the image should be pushed. Do this in mysql-schema/pom.xml. In the example below I'm setting it to
+the [Container Registry](https://cloud.google.com/container-registry/) in Google Cloud Europe. 
+
+```xml
+<to>
+   <image>eu.gcr.io/my-gcp-project/mysql-operator</image>
+</to>
+```
+
+1. The following Maven command will build the JAR file, package it as a Docker image and push it to the registry.
+
+   `mvn jib:dockerBuild` 
+
+1. Deploy the test MySQL on your cluster if you want to use it. Note that if you have an already running MySQL server
+you want to use, you can skip this step, but you will have to configure the operator to use that server.
+
+   `kubectl apply -f k8s/mysql-db.yaml`
+1. Deploy the CRD: 
+
+   `kubectl apply -f k8s/crd.yaml`
+
+1. Make a copy of `k8s/operator.yaml` and replace ${DOCKER_REGISTRY} and ${OPERATOR_VERSION} to the 
+right values. You will want to set `OPERATOR_VERSION` to the one used for building the Docker image. `DOCKER_REGISTRY` should
+be the same as you set the docker-registry property in your `pom.xml`.
+If you look at the environment variables you will notice this is where the access to the MySQL server is configured.
+The default values assume the server is running in another Kubernetes namespace (called `mysql`), uses the `root` user
+with a not very secure password. In case you want to use a different MySQL server, this is where you configure it. 
+
+1. Run `kubectl apply -f copy-of-operator.yaml` to deploy the operator. You can wait for the deployment to succeed using
+this command: `kubectl rollout status deployment mysql-schema-operator -w`. `-w` will cause kubectl to continuously monitor 
+the deployment until you stop it.
+
+1. Now you are ready to create some databases! To create a database schema called `mydb` just apply the `k8s/schema.yaml`
+file with kubectl: `kubectl apply -f k8s/schema.yaml`. You can modify the database name in the file to create more schemas.

sample-operators/mysql-schema/k8s/mysql-deployment.yaml

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+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: mysql
+spec:
+  selector:
+    matchLabels:
+      app: mysql
+  strategy:
+    type: Recreate
+  template:
+    metadata:
+      labels:
+        app: mysql
+    spec:
+      containers:
+      - image: mysql:5.6
+        name: mysql
+        env:
+        # Use secret in real usage
+        - name: MYSQL_ROOT_PASSWORD
+          value: password
+        ports:
+        - containerPort: 3306
+          name: mysql

sample-operators/mysql-schema/k8s/mysql-service.yaml

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+apiVersion: v1
+kind: Service
+metadata:
+  name: mysql
+spec:
+  ports:
+  - port: 3306
+  selector:
+    app: mysql
+  type: LoadBalancer

sample-operators/mysql-schema/k8s/operator.yaml

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+apiVersion: v1
+kind: Namespace
+metadata:
+  name: mysql-schema-operator
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: mysql-schema-operator
+  namespace: mysql-schema-operator
+spec:
+  selector:
+    matchLabels:
+      app: mysql-schema-operator
+  replicas: 1 # we always run a single replica of the operator to avoid duplicate handling of events
+  strategy:
+    type: Recreate # during an upgrade the operator will shut down before the new version comes up to prevent two instances running at the same time
+  template:
+    metadata:
+      labels:
+        app: mysql-schema-operator
+    spec:
+      serviceAccountName: mysql-schema-operator # specify the ServiceAccount under which's RBAC persmissions the operator will be executed under
+      containers:
+      - name: operator
+        image: ${DOCKER_REGISTRY}/mysql-schema-operator:${OPERATOR_VERSION}
+        imagePullPolicy: Always
+        ports:
+        - containerPort: 80
+        env:
+        - name: MYSQL_HOST
+          value: mysql.mysql # assuming the MySQL server runs in a namespace called "mysql" on Kubernetes
+        - name: MYSQL_USER
+          value: root
+        - name: MYSQL_PASSWORD
+          value: password # sample-level security
+        readinessProbe:
+          httpGet:
+            path: /health # when this returns 200 the operator is considered up and running
+            port: 8080
+          initialDelaySeconds: 1
+          timeoutSeconds: 1
+        livenessProbe:
+          httpGet:
+            path: /health # when this endpoint doesn't return 200 the operator is considered broken and get's restarted
+            port: 8080
+          initialDelaySeconds: 30
+          timeoutSeconds: 1
+
+---
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: mysql-schema-operator
+  namespace: mysql-schema-operator
+
+---
+apiVersion: rbac.authorization.k8s.io/v1beta1
+kind: ClusterRole
+metadata:
+  name: mysql-schema-operator
+rules:
+- apiGroups:
+  - mysql.sample.javaoperatorsdk
+  resources:
+  - schemas
+  verbs:
+  - "*"
+- apiGroups:
+  - mysql.sample.javaoperatorsdk
+  resources:
+  - schemas/status
+  verbs:
+  - "*"
+- apiGroups:
+  - apiextensions.k8s.io
+  resources:
+  - customresourcedefinitions
+  verbs:
+  - "get"
+  - "list"
+- apiGroups:
+  - ""
+  resources:
+  - secrets
+  verbs:
+  - "*"
+
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: mysql-schema-operator
+subjects:
+- kind: ServiceAccount
+  name: mysql-schema-operator
+  namespace: mysql-schema-operator
+roleRef:
+  kind: ClusterRole
+  name: mysql-schema-operator
+  apiGroup: ""

sample-operators/mysql-schema/k8s/schema.yaml

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+apiVersion: "mysql.sample.javaoperatorsdk/v1"
+kind: MySQLSchema
+metadata:
+  name: mydb
+spec:
+  encoding: utf8

sample-operators/mysql-schema/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>io.javaoperatorsdk</groupId>
+        <artifactId>sample-operators</artifactId>
+        <version>2.0.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>sample-mysql-schema-operator</artifactId>
+    <name>Operator SDK - Samples - MySQL Schema</name>
+    <description>Provisions Schemas in a MySQL database</description>
+    <packaging>jar</packaging>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+        <jib-maven-plugin.version>3.1.4</jib-maven-plugin.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.javaoperatorsdk</groupId>
+            <artifactId>operator-framework</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.takes</groupId>
+            <artifactId>takes</artifactId>
+            <version>1.19</version>
+        </dependency>
+        <dependency>
+            <groupId>mysql</groupId>
+            <artifactId>mysql-connector-java</artifactId>
+            <version>8.0.26</version>
+        </dependency>
+        <dependency>
+            <groupId>io.fabric8</groupId>
+            <artifactId>crd-generator-apt</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-slf4j-impl</artifactId>
+            <version>2.13.3</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.awaitility</groupId>
+            <artifactId>awaitility</artifactId>
+            <version>4.1.0</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.dataformat</groupId>
+            <artifactId>jackson-dataformat-yaml</artifactId>
+            <version>2.13.0</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>com.google.cloud.tools</groupId>
+                <artifactId>jib-maven-plugin</artifactId>
+                <version>${jib-maven-plugin.version}</version>
+                <configuration>
+                    <from>
+                        <image>gcr.io/distroless/java:11</image>
+                    </from>
+                    <to>
+                        <image>mysql-schema-operator</image>
+                    </to>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

sample-operators/mysql-schema/src/main/java/io/javaoperatorsdk/operator/sample/MySQLDbConfig.java

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+package io.javaoperatorsdk.operator.sample;
+
+import org.apache.commons.lang3.ObjectUtils;
+
+public class MySQLDbConfig {
+
+  private final String host;
+  private final String port;
+  private final String user;
+  private final String password;
+
+  public MySQLDbConfig(String host, String port, String user, String password) {
+    this.host = host;
+    this.port = port != null ? port : "3306";
+    this.user = user;
+    this.password = password;
+  }
+
+  public static MySQLDbConfig loadFromEnvironmentVars() {
+    if (ObjectUtils.anyNull(System.getenv("MYSQL_HOST"),
+        System.getenv("MYSQL_USER"), System.getenv("MYSQL_PASSWORD"))) {
+      throw new IllegalStateException("Mysql server parameters not defined");
+    }
+    return new MySQLDbConfig(System.getenv("MYSQL_HOST"),
+        System.getenv("MYSQL_PORT"),
+        System.getenv("MYSQL_USER"),
+        System.getenv("MYSQL_PASSWORD"));
+  }
+
+  public String getHost() {
+    return host;
+  }
+
+  public String getPort() {
+    return port;
+  }
+
+  public String getUser() {
+    return user;
+  }
+
+  public String getPassword() {
+    return password;
+  }
+}
+

sample-operators/mysql-schema/src/main/java/io/javaoperatorsdk/operator/sample/MySQLSchema.java

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+package io.javaoperatorsdk.operator.sample;
+
+import io.fabric8.kubernetes.api.model.Namespaced;
+import io.fabric8.kubernetes.client.CustomResource;
+import io.fabric8.kubernetes.model.annotation.Group;
+import io.fabric8.kubernetes.model.annotation.Version;
+
+@Group("mysql.sample.javaoperatorsdk")
+@Version("v1")
+public class MySQLSchema extends CustomResource<SchemaSpec, SchemaStatus> implements Namespaced {
+}