Added Circuit Breaker for API Gateway (Cloud Gateway Service) with Monitoring...

Added Circuit Breaker for API Gateway (Cloud Gateway Service) with Monitoring using Prometheus and Grafana

MicroServices/CloudGateway/pom.xml

@@ -27,6 +27,15 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-actuator</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-circuitbreaker-reactor-resilience4j</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.micrometer</groupId>
+            <artifactId>micrometer-registry-prometheus</artifactId>
+            <scope>runtime</scope>
+        </dependency>
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-gateway</artifactId>
@@ -51,26 +60,6 @@
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
-<!--            <dependency>-->
-<!--                <groupId>org.slf4j</groupId>-->
-<!--                <artifactId>slf4j-api</artifactId>-->
-<!--                <version>2.0.9</version>-->
-<!--            </dependency>-->
-<!--            <dependency>-->
-<!--                <groupId>ch.qos.logback</groupId>-->
-<!--                <artifactId>logback-classic</artifactId>-->
-<!--                <version>1.4.11</version>-->
-<!--            </dependency>-->
-<!--            <dependency>-->
-<!--                <groupId>ch.qos.logback</groupId>-->
-<!--                <artifactId>logback-core</artifactId>-->
-<!--                <version>1.4.11</version>-->
-<!--            </dependency>-->
-<!--            <dependency>-->
-<!--                <groupId>com.google.code.gson</groupId>-->
-<!--                <artifactId>gson</artifactId>-->
-<!--                <version>2.8.9</version>-->
-<!--            </dependency>-->
         </dependencies>
 
     </dependencyManagement>

MicroServices/CloudGateway/src/main/java/org/example/FallbackMethod.java

+package org.example;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+
+@RestController
+@RequestMapping("/")
+public class FallbackMethod {
+
+    @RequestMapping("user-fallback")
+    public String getCatalogFallback(){
+        //it can be an empty list of books or last cash result
+        return "User Service Service is temporary unavailable, Please Try Again Later";
+    }
+
+    @RequestMapping("database-fallback")
+    public String getMovieFallback(){
+        //it can be an empty list of books or last cash result
+        return "Database Service is temporary unavailable, Please Try Again Later";
+    }
+    @RequestMapping("weather-fallback")
+    public String getRatingFallback(){
+        //it can be an empty list of books or last cash result
+        return "Weather Service is temporary unavailable, Please Try Again Later";
+    }
+}

MicroServices/CloudGateway/src/main/resources/application.yml

@@ -12,14 +12,32 @@ spring:
           predicates:
             - Path=/users-db/**
             - Path=/flights-db/**
+          filters:
+            - name: CircuitBreaker
+              args:
+                name: databaseCircuitBreaker
+                fallbackUri: forward:/database-fallback
+
         - id: UserService
           uri: lb://user-service
           predicates:
             - Path=/users/**
+          filters:
+            - name: CircuitBreaker
+              args:
+                name: userCircuitBreaker
+                fallbackUri: forward:/user-fallback
+
         - id: WeatherService
           uri: lb://weather-service
           predicates:
             - Path=/weather/**
+          filters:
+            - name: CircuitBreaker
+              args:
+                name: weatherCircuitBreaker
+                fallbackUri: forward:/weather-fallback
+
 
 eureka:
   client:
@@ -28,6 +46,28 @@ eureka:
     service-url:
       default-zone: http://localhost:8761/eureka/
 
-#  instance:
-#    hostname: localhost
-#    preferIpAddress: true
\ No newline at end of file
+management:
+  health:
+    circuitbreakers:
+      enabled: true
+  endpoints:
+    web:
+      exposure:
+        include: health,prometheus
+  endpoint:
+    health:
+      show-details: always
+
+resilience4j:
+  circuitbreaker:
+    instances:
+      userCircuitBreaker:
+        registerHealthIndicator: true
+        eventConsumerBufferSize: 10
+        failureRateThreshold: 50
+        minimumNumberOfCalls: 5
+        automaticTransitionFromOpenToHalfOpenEnabled: true
+        waitDurationInOpenState: 10s
+        permittedNumberOfCallsInHalfOpenState: 3
+        slidingWindowSize: 10
+        slidingWindowType: COUNT_BASED
\ No newline at end of file

MicroServices/CloudGateway/target/classes/application.yml

@@ -12,14 +12,32 @@ spring:
           predicates:
             - Path=/users-db/**
             - Path=/flights-db/**
+          filters:
+            - name: CircuitBreaker
+              args:
+                name: databaseCircuitBreaker
+                fallbackUri: forward:/database-fallback
+
         - id: UserService
           uri: lb://user-service
           predicates:
             - Path=/users/**
+          filters:
+            - name: CircuitBreaker
+              args:
+                name: userCircuitBreaker
+                fallbackUri: forward:/user-fallback
+
         - id: WeatherService
           uri: lb://weather-service
           predicates:
             - Path=/weather/**
+          filters:
+            - name: CircuitBreaker
+              args:
+                name: weatherCircuitBreaker
+                fallbackUri: forward:/weather-fallback
+
 
 eureka:
   client:
@@ -28,6 +46,28 @@ eureka:
     service-url:
       default-zone: http://localhost:8761/eureka/
 
-#  instance:
-#    hostname: localhost
-#    preferIpAddress: true
\ No newline at end of file
+management:
+  health:
+    circuitbreakers:
+      enabled: true
+  endpoints:
+    web:
+      exposure:
+        include: health,prometheus
+  endpoint:
+    health:
+      show-details: always
+
+resilience4j:
+  circuitbreaker:
+    instances:
+      userCircuitBreaker:
+        registerHealthIndicator: true
+        eventConsumerBufferSize: 10
+        failureRateThreshold: 50
+        minimumNumberOfCalls: 5
+        automaticTransitionFromOpenToHalfOpenEnabled: true
+        waitDurationInOpenState: 10s
+        permittedNumberOfCallsInHalfOpenState: 3
+        slidingWindowSize: 10
+        slidingWindowType: COUNT_BASED
\ No newline at end of file

MicroServices/ReadME.txt

+# Mini-Catalog Microservices Application
+
+
+## Application Services
+### Spring Boot APP
+- Weather Service
+- User Service
+- DataBase Service
+### Spring Cloud APP
+- Service Discovery (DiscAndReg)
+- Cloud Gateway
+## Monitoring with Prometheus and Grafana
+
+### Requirements
+[Docker](https://docs.docker.com/install/) and [Docker Compose](https://docs.docker.com/compose/install/) installed.
+
+### Step 1
+Use docker-compose to start Grafana and Prometheus servers.
+- In the root folder
+```sh
+docker-compose -f docker-compose.yml up
+```
+### Step 2
+Check the Prometheus server.
+- Open http://localhost:9091
+- Access status -> Targets, both endpoints must be "UP"
+
+### Step 3
+Configure the Grafana.
+- Open http://localhost:3000
+- **Configure integration with Prometheus**
+    - Access configuration
+    - Add data source
+    - Select Prometheus
+    - Use url "http://prometheus:9090" and access with value "Browser"
+- **Configure dashboard**
+    - Access "home"
+    - Import dashboard
+    - Upload dashboard.json from /docker

MicroServices/docker-compose.yml

+version: '3'
+services:
+  prometheus:
+    image: prom/prometheus
+    container_name: prometheus
+    volumes:
+      - ./docker/prometheus-desktop.yml:/etc/prometheus/prometheus.yml
+    ports:
+      - "9091:9090"
+    networks:
+      - net
+  grafana:
+    image: grafana/grafana
+    container_name: grafana
+    env_file:
+      - ./docker/grafana.env
+    ports:
+      - "3000:3000"
+    networks:
+      - net
+networks:
+  net:
\ No newline at end of file

MicroServices/docker/grafana.env

+# [server]
+# GF_SERVER_DOMAIN=localhost
+# GF_SERVER_HTTP_PORT=3000
+# GF_SERVER_PROTOCOL=http
\ No newline at end of file

MicroServices/docker/prometheus-desktop.yml

+
+global:
+  scrape_interval:     15s # By default, scrape targets every 15 seconds.
+
+  # Attach these labels to any time series or alerts when communicating with
+  # external systems (federation, remote storage, Alertmanager).
+  external_labels:
+    monitor: 'resilience4j-monitor'
+
+# A scrape configuration containing exactly one endpoint to scrape:
+# Here it's Prometheus itself.
+scrape_configs:
+  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
+  - job_name: 'prometheus'
+
+    # Override the global default and scrape targets from this job every 5 seconds.
+    scrape_interval: 5s
+
+    static_configs:
+      - targets: ['localhost:9090']
+
+  - job_name:       'Cloud-Gateway'
+
+    # Override the global default and scrape targets from this job every 5 seconds.
+    scrape_interval: 5s
+
+    metrics_path: /actuator/prometheus
+
+    static_configs:
+      # Use the service name (see docker-compose.yml) instead of localhost
+      - targets: ['host.docker.internal:9090']