added fallback defaults for env vars

dispatch/src/main.go

@@ -112,7 +112,12 @@ func main() {
         LogLevel: instana.Info}))
 
     // Init amqpUri
-    amqpUri = fmt.Sprintf("amqp://guest:guest@%s:5672/", os.Getenv("AMQP_HOST"))
+    // get host from environment
+    amqpHost, ok := os.LookupEnv("AMQP_HOST")
+    if !ok {
+        amqpHost = "rabbitmq"
+    }
+    amqpUri = fmt.Sprintf("amqp://guest:guest@%s:5672/", amqpHost)
 
     // MQ error channel
     rabbitCloseError = make(chan *amqp.Error)

payment/payment.py

@@ -14,6 +14,9 @@ from rabbitmq import Publisher
 
 app = Flask(__name__)
 
+CART = os.getenv('CART_HOST', 'cart')
+USER = os.getenv('USER_HOST', 'user')
+
 @app.route('/health', methods=['GET'])
 def health():
     return 'OK'
@@ -33,13 +36,13 @@ def pay(id):
     queueOrder({ 'orderid': orderid, 'user': id, 'cart': cart })
 
     # add to history
-    req = requests.post('http://user:8080/order/' + id,
+    req = requests.post('http://{user}:8080/order/{id}'.format(user=USER, id=id),
             data=json.dumps({'orderid': orderid, 'cart': cart}),
             headers={'Content-Type': 'application/json'})
     app.logger.info('order history returned {}'.format(req.status_code))
 
     # delete cart
-    req = requests.delete('http://cart:8080/cart/' + id);
+    req = requests.delete('http://{cart}:8080/cart/{id}'.format(cart=CART, id=id));
     app.logger.info('cart delete returned {}'.format(req.status_code))
 
     return jsonify({ 'orderid': orderid })

payment/rabbitmq.py

@@ -3,7 +3,7 @@ import pika
 import os
 
 class Publisher:
-    HOST = os.getenv("AMQP_HOST", "rabbitmq")
+    HOST = os.getenv('AMQP_HOST', 'rabbitmq')
     VIRTUAL_HOST = '/'
     EXCHANGE='robot-shop'
     TYPE='direct'

shipping/service/src/main/java/org/steveww/spark/Main.java

@@ -37,9 +37,8 @@ public class Main {
 
     public static void main(String[] args) {
         // Get ENV configuration values
-        Map<String, String> env = System.getenv();
-        CART_URL = String.format("http://%s/shipping/", env.get("CART_ENDPOINT"));
-        JDBC_URL = String.format("jdbc:mysql://%s/cities?useSSL=false&autoReconnect=true", env.get("DB_HOST"));
+        CART_URL = String.format("http://%s/shipping/", System.getenv("CART_ENDPOINT") != null ? System.getenv("CART_ENDPOINT") : "cart");
+        JDBC_URL = String.format("jdbc:mysql://%s/cities?useSSL=false&autoReconnect=true", System.getenv("DB_HOST") != null ? System.getenv("DB_HOST") : "mysql");
 
         //
         // Create database connector