cellery hello world api sample 🎉

hello-world-api/Makefile

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+#  Copyright (c) 2019 WSO2 Inc. (http:www.wso2.org) All Rights Reserved.
+#
+#  WSO2 Inc. licenses this file to you 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, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+
+PROJECT_ROOT := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
+DOCKER_REPO ?= wso2cellery
+DOCKER_IMAGE_TAG ?= latest
+
+SAMPLE := hello-world-api
+COMPONENT := hello-service
+
+all: clean build docker
+
+.PHONY: clean.$(SAMPLE)
+clean.$(SAMPLE): clean
+
+.PHONY: check-style.$(SAMPLE)
+check-style.$(SAMPLE): check-style
+
+.PHONY: build.$(SAMPLE)
+build.$(SAMPLE): build
+
+.PHONY: docker.$(SAMPLE)
+docker.$(SAMPLE): docker
+
+.PHONY: docker-push.$(SAMPLE)
+docker-push.$(SAMPLE): docker-push
+
+.PHONY: clean
+clean:
+	cd components/$(COMPONENT); \
+	rm -f hello-service
+
+.PHONY: check-style
+check-style:
+	@:
+
+PHONY: build
+build:
+	cd components/$(COMPONENT); \
+	CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o hello-service hello-service.go
+
+.PHONY: docker
+docker:
+	cd components/$(COMPONENT); \
+	docker build -t ${DOCKER_REPO}/samples-$(SAMPLE):${DOCKER_IMAGE_TAG} .
+
+.PHONY: docker-push
+docker-push:
+	cd components/$(COMPONENT); \
+	docker push ${DOCKER_REPO}/samples-$(SAMPLE):${DOCKER_IMAGE_TAG}

hello-world-api/README.md

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+Hello World API
+===============
+
+Hello World API sample is a simple rest API that returns the text 'Hello World!' as a response to a GET request.
+
+## Getting Started
+
+### Checkout the Sample
+
+1. Clone the [wso2-cellery/samples](https://github.com/wso2-cellery/samples) repository.
+
+2. Navigate to the hello-world-api Sample.
+   ```
+   cd <SAMPLES_ROOT>/hello-world-api
+   ```
+
+### Running the Hello World API Cell
+
+1. Build the hello-world-api Cell.
+   ```
+   cellery build hello-world-api.bal wso2cellery/hello-world-api:0.1.0
+   ```
+2. Deploy the hello-world Cell
+   ```
+   cellery run wso2cellery/hello-world-api:0.1.0 -n my-hello-api
+   ```
+3. Check the running Cell. 
+   ```
+   cellery status my-hello-api
+   ```
+   Once the status becomes 'Ready' you can go ahead and invoke it. 
+
+4. Invoking the Hello World API
+
+    By default, the Cellery installation will be using the following domain names for the relevant components in Cellery: 
+    * cellery-dashboard
+    * wso2-apim-gateway
+    * cellery-k8s-metrics
+    * wso2-apim
+    * idp.cellery-system
+    * wso2sp-observability-api
+
+    These domains should be mapped to the IP of Kubernetes Ingress Controller in the Cellery installation.   
+
+    To invoke the API, an oauth2 token should be obtained from the API store, as described in the following steps:
+
+    1. Login to the [API Store](https://wso2-apim/store/) using admin:admin credentials.
+
+    2. Click on ‘my_hello_api_global_1_0_0_hello’ to create a subscription and generate a token. 
+       (See  [Subscribing to an API](https://docs.wso2.com/display/AM260/Subscribe+to+an+API))
+
+    Once you have subscribed to the API and generated a token, invoke the API passing the same as a Bearer token:
+    ```
+    curl -H "Authorization: Bearer <token>" https://wso2-apim-gateway/my-hello-api/hello/ -kv
+    ```
+
+## Building the Components from Source
+
+You do not need to build the Components if you just wish to deploy the Cells. This should only be done if you wish to change the Hello World API sample and play around with it.
+
+### Prerequisites
+
+* Docker
+* GNU Make 4.1+
+
+### Building the Components
+
+If you wish to change the Hello World API Sample and play around with Cellery, you can follow this section to rebuild the Components.
+
+1. [Checkout](#checkout-the-sample) the Sample
+2. Set the following environment variables for customizing the build.
+
+   | Environment Variable  |                                                                       |
+   |-----------------------|-----------------------------------------------------------------------|
+   | DOCKER_REPO           | The name of the repository of the Docker images (Your Docker Hub ID)  |
+   | DOCKER_IMAGE_TAG      | The tag of the Docker images                                          |
+
+3. Run the make target for building docker images.
+   ```
+   make docker
+   ```
+   This would build the components from source and build the docker images using the environment variables you have provided.
+4. Login to Docker Hub
+   ```
+   docker login
+   ```
+5. Run the target for pushing the docker images.
+   ```
+   make docker-push
+   ```
+6. Update the `<SAMPLES_ROOT>/hello-world-api/hello-world-api.bal` file and set the newly created image names for the component source.
+7. [Build and run](#getting-started) the Cells.

hello-world-api/components/hello-service/Dockerfile

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+FROM scratch
+COPY hello-service /
+ENTRYPOINT ["/hello-service","-logtostderr=true"]

hello-world-api/components/hello-service/hello-service.go

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+/*
+ * Copyright (c) 2019 WSO2 Inc. (http:www.wso2.org) All Rights Reserved.
+ *
+ * WSO2 Inc. licenses this file to you 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, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func main() {
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "Hello World! \n")
+	})
+
+	fmt.Println("hello service is listening on port 9090")
+	http.ListenAndServe(":9090", nil)
+}

hello-world-api/hello-world-api.bal

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+//
+//  Copyright (c) 2019 WSO2 Inc. (http:www.wso2.org) All Rights Reserved.
+//
+//  WSO2 Inc. licenses this file to you 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, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+//  KIND, either express or implied.  See the License for the
+//  specific language governing permissions and limitations
+//  under the License.
+//
+
+import ballerina/io;
+import celleryio/cellery;
+
+//Hello World Component
+cellery:Component helloComponent = {
+    name: "hello-api",
+    source: {
+        image: "docker.io/wso2cellery/samples-hello-world-api"
+    },
+    ingresses: {
+        helloApi: <cellery:HttpApiIngress>{ port: 9090,
+            context: "hello",
+            definition: {
+                resources: [
+                    {
+                        path: "/",
+                        method: "GET"
+                    }
+                ]
+            },
+            expose: "global"
+        }
+    }
+};
+
+cellery:CellImage helloCell = {
+    components: {
+        helloComp: helloComponent
+    }
+};
+
+public function build(cellery:ImageName iName) returns error? {
+    //Build Hello Cell
+    io:println("Building Hello World Cell ...");
+    return cellery:createImage(helloCell, iName);
+}