Application Layer

Setup

ALFI is currently in an open beta.

Step by step

In a hurry? Skip to Complete examples.

Construct an ApplicationCoordinates instance.
Construct a TrafficCoordinates instance.
Optionally (if using a custom TrafficCoordinates instance) construct a GremlinService singleton.
Optionally (if using a custom TrafficCoordinates instance) inject the fault using com.gremlin.GremlinService#applyImpact(trafficCoordinates). Add this line of code anywhere in your application, you wish the fault to be injected.
Click here to create a new Attack.
Select an Application Query.
Set the necessary fields for the selected Application Query.
- These are defined when setting up the ApplicationCoordinates.
Select a Traffic Query.
- These are defined when setting up the TrafficCoordinates.
Choose a Gremlin attack - Set the amount of latency in ms to apply and optionally throw a RuntimeException within your application.
Run the attack - Set the duration in seconds for how long the attack will last.
Test your application to observe the impact of the attack.

Complete examples

ALFI AWS

This example has been developed for AWS Lambda but could be used in any application one deploys to AWS. Include alfi-aws jar in your calasspath to use this library.
Source code: https://github.com/gremlin/alfi-lambda

java

1package com.alfilambda;
2
3import com.amazonaws.services.lambda.runtime.Context;
4import com.amazonaws.services.lambda.runtime.LambdaLogger;
5import com.amazonaws.services.lambda.runtime.RequestHandler;
6import com.gremlin.*;
7import com.gremlin.aws.AwsApplicationCoordinatesResolver;
8
9import java.time.Duration;
10import java.time.Instant;
11import java.util.Map;
12
13public class AlfiDemoHandler implements RequestHandler<Map<String,String>, String> {
14
15    private final GremlinService gremlinService;
16
17    public AlfiDemoHandler() {
18        final GremlinServiceFactory factory = new GremlinServiceFactory(new GremlinCoordinatesProvider() {
19            @Override
20            public ApplicationCoordinates initializeApplicationCoordinates() {
21                ApplicationCoordinates coords = AwsApplicationCoordinatesResolver.inferFromEnvironment()
22                        .orElseThrow(IllegalStateException::new);
23                return coords;
24            }
25        });
26        gremlinService = factory.getGremlinService();
27    }
28
29    @Override
30    public String handleRequest(Map<String, String> input, Context context) {
31        Instant start = Instant.now();
32        TrafficCoordinates trafficCoordinates = new TrafficCoordinates.Builder()
33                .withType(this.getClass().getSimpleName())
34                .withField("method", "handleRequest")
35                .build();
36        gremlinService.applyImpact(trafficCoordinates);
37        LambdaLogger logger = context.getLogger();
38        Instant finish = Instant.now();
39        long timeElapsed = Duration.between(start, finish).toMillis();  //in millis
40        logger.log(String.format("Lambda took %s millis", timeElapsed));
41        return new String("200 OK");
42    }
43}

Click here to create a new Attack
See Attack and Lambda setup here: https://github.com/gremlin/alfi-lambda/blob/master/README.md

ALFI DynamoDB

This example uses Spring for Dependency Injection and the alfi-aws-dynamodb-client jar.
Source code: https://github.com/gremlin/alfi-dynamodb

java

1package com.example.alfidynamodb.config;
2
3import com.amazonaws.ClientConfiguration;
4import com.amazonaws.handlers.RequestHandler2;
5import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
6import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
7import com.gremlin.*;
8import com.gremlin.aws.GremlinDynamoRequestInterceptor;
9import org.springframework.beans.factory.annotation.Value;
10import org.springframework.context.annotation.Bean;
11import org.springframework.context.annotation.Configuration;
12@Configuration
13public class AlfiConfig {
14
15    private static final String APPLICATION_QUERY_NAME = "ALFIDemoApplication";
16    private static final int CLIENT_EXECUTION_TIMEOUT = 1500;
17    private static final int CLIENT_REQUEST_TIMEOUT = 500;
18
19    @Value("${aws.region}")
20    private String region;
21
22
23    public GremlinCoordinatesProvider gremlinCoordinatesProvider() {
24        return new GremlinCoordinatesProvider() {
25            @Override
26            public ApplicationCoordinates initializeApplicationCoordinates() {
27                return new ApplicationCoordinates.Builder()
28                        .withType(APPLICATION_QUERY_NAME)
29                        .build();
30            }
31        };
32    }
33
34    public GremlinServiceFactory gremlinServiceFactory() {
35        return new GremlinServiceFactory(gremlinCoordinatesProvider());
36    }
37
38    public GremlinService gremlinService() {
39        return gremlinServiceFactory().getGremlinService();
40    }
41
42    @Bean
43    public AmazonDynamoDB amazonDynamoDB() {
44        final RequestHandler2 gremlinDynamoInterceptor = new GremlinDynamoRequestInterceptor(gremlinService(), CLIENT_EXECUTION_TIMEOUT, CLIENT_REQUEST_TIMEOUT);
45        return AmazonDynamoDBClientBuilder.standard()
46                .withRegion(region)
47                .withClientConfiguration(new ClientConfiguration()
48                        .withClientExecutionTimeout(CLIENT_EXECUTION_TIMEOUT)
49                        .withConnectionTimeout(CLIENT_REQUEST_TIMEOUT)
50                        .withMaxErrorRetry(2)
51                )
52                .withRequestHandlers(gremlinDynamoInterceptor).build();
53    }
54
55}

java

1package com.example.alfidynamodb.persistence;
2
3import com.amazonaws.AmazonServiceException;
4import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
5import com.amazonaws.services.dynamodbv2.model.AttributeValue;
6import com.amazonaws.services.dynamodbv2.model.GetItemRequest;
7import com.amazonaws.services.kms.model.NotFoundException;
8import org.slf4j.Logger;
9import org.slf4j.LoggerFactory;
10import org.springframework.beans.factory.annotation.Autowired;
11import org.springframework.beans.factory.annotation.Value;
12import org.springframework.stereotype.Component;
13
14import java.util.HashMap;
15import java.util.Map;
16@Component
17public class GetItemRequester {
18
19    private final Logger LOG = LoggerFactory.getLogger(getClass().getName());
20
21    @Value("${dynamo.db.table}")
22    private String table;
23
24    private final AmazonDynamoDB amazonDynamoDB;
25
26    public GetItemRequester(@Autowired AmazonDynamoDB amazonDynamoDB) {
27        this.amazonDynamoDB = amazonDynamoDB;
28    }
29
30    public Map<String, AttributeValue> getItem(String id) {
31        long startTime = System.currentTimeMillis();
32        try {
33
34            LOG.info(String.format("Querying DynamoDB for item with ID %s...", id));
35            Map<String, AttributeValue> returnedItem = amazonDynamoDB.getItem(createRequestWithId(id)).getItem();
36            if (returnedItem != null) {
37                return returnedItem;
38            } else {
39                throw new NotFoundException(String.format("Item with id %s not found!", id));
40            }
41        } catch (AmazonServiceException e) {
42            LOG.error(e.getMessage());
43            throw e;
44        } finally {
45            long endTime = System.currentTimeMillis();
46            long duration = (endTime - startTime);
47            LOG.info(String.format("Call to DynamoDB took %s milliseconds.", duration));
48        }
49    }
50
51    private GetItemRequest createRequestWithId(String id) {
52        HashMap<String, AttributeValue> keyToGet = new HashMap<>();
53        keyToGet.put("id", new AttributeValue(id));
54        return new GetItemRequest().withKey(keyToGet).withTableName(table);
55    }
56}

Click here to create a new Attack
Fill out the Application Query and Traffic Query fields to match this example:

ALFI HTTP Servlet Filter

This example uses Spring for Dependency Injection and the alfi-http-servlet-filter jar.
Source code: https://github.com/gremlin/books-demo

java

1package com.example.rec;
2
3import com.gremlin.ApplicationCoordinates;
4import com.gremlin.GremlinCoordinatesProvider;
5import com.gremlin.GremlinService;
6import com.gremlin.GremlinServiceFactory;
7import com.gremlin.http.servlet.GremlinServletFilter;
8import org.springframework.boot.web.servlet.FilterRegistrationBean;
9import org.springframework.context.annotation.Bean;
10import org.springframework.context.annotation.Configuration;
11
12@Configuration
13public class WebConfig {
14
15    @Bean
16    public FilterRegistrationBean recommendationsFilterRegistrationBean() {
17        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
18        registrationBean.setName("recs");
19
20        final GremlinCoordinatesProvider alfiCoordinatesProvider = new GremlinCoordinatesProvider() {
21            @Override
22            public ApplicationCoordinates initializeApplicationCoordinates() {
23                return new ApplicationCoordinates.Builder()
24                        .withType("local")
25                        .withField("service", "recommendations")
26                        .build();
27            }
28        };
29        final GremlinServiceFactory alfiFactory = new GremlinServiceFactory(alfiCoordinatesProvider);
30        final GremlinService alfi = alfiFactory.getGremlinService();
31
32        GremlinServletFilter alfiFilter = new GremlinServletFilter(alfi);
33        registrationBean.setFilter(alfiFilter);
34        registrationBean.setOrder(1);
35        return registrationBean;
36    }
37
38}

There is no need to define a TrafficCoordinates when using the GremlinServletFilter. This library takes care of that for you.

This enables you to target any verb and any route hosted by your application! For example, you could narrow the blast radius of an attack to only GET requests to https://somehost/recommendations.

Click here to create a new Attack
Fill out the Application Query and Traffic Query fields to match this example:

ALFI Apache Http Client

This example uses Spring for Dependency Injection and the alfi-apache-http-client jar.
Source code: https://github.com/gremlin/alfi-apache-http-client

java

1package com.example.alfiapachehttpclient.config;
2
3import org.springframework.context.annotation.Bean;
4import org.springframework.context.annotation.Configuration;
5import com.gremlin.*;
6
7@Configuration
8public class ALFIConfig {
9
10    private static final String APPLICATION_QUERY_NAME = "ALFIApacheHttpClientDemo";
11
12    public GremlinCoordinatesProvider gremlinCoordinatesProvider() {
13        return new GremlinCoordinatesProvider() {
14            @Override
15            public ApplicationCoordinates initializeApplicationCoordinates() {
16                return new ApplicationCoordinates.Builder()
17                        .withType(APPLICATION_QUERY_NAME)
18                        .build();
19            }
20        };
21    }
22
23    public GremlinServiceFactory gremlinServiceFactory() {
24        return new GremlinServiceFactory(gremlinCoordinatesProvider());
25    }
26
27    @Bean
28    public GremlinService gremlinService() {
29        return gremlinServiceFactory().getGremlinService();
30    }
31
32}

java

1package com.example.alfiapachehttpclient.config;
2
3import com.gremlin.GremlinService;
4import com.gremlin.http.client.GremlinApacheHttpRequestInterceptor;
5import org.apache.http.client.config.RequestConfig;
6import org.apache.http.impl.client.CloseableHttpClient;
7import org.apache.http.impl.client.HttpClientBuilder;
8import org.springframework.beans.factory.annotation.Autowired;
9import org.springframework.context.annotation.Bean;
10import org.springframework.context.annotation.Configuration;
11
12@Configuration
13public class ApacheClientConfig {
14
15    private final GremlinService gremlinService;
16    private static final int CONNECTION_TIMEOUT = 1000;
17    private static final int SOCKET_TIMEOUT = 3000;
18
19    @Autowired
20    public ApacheClientConfig(GremlinService gremlinService) {
21        this.gremlinService = gremlinService;
22    }
23
24    @Bean
25    public CloseableHttpClient closableHttpClient() {
26        RequestConfig requestConfig = RequestConfig.custom()
27                .setConnectTimeout(CONNECTION_TIMEOUT)
28                .setSocketTimeout(SOCKET_TIMEOUT)
29                .build();
30
31        final GremlinApacheHttpRequestInterceptor gremlinInterceptor =
32                new GremlinApacheHttpRequestInterceptor(gremlinService, "alfi-client-demo");
33        final HttpClientBuilder clientBuilder = HttpClientBuilder
34                .create()
35                .addInterceptorFirst(gremlinInterceptor)
36                .setDefaultRequestConfig(requestConfig);
37
38        return clientBuilder.build();
39    }
40
41
42}

java

1package com.example.alfiapachehttpclient.controller;
2
3import org.apache.http.HttpEntity;
4import org.apache.http.client.methods.CloseableHttpResponse;
5import org.apache.http.client.methods.HttpGet;
6import org.apache.http.impl.client.CloseableHttpClient;
7import org.apache.http.util.EntityUtils;
8import org.slf4j.Logger;
9import org.slf4j.LoggerFactory;
10import org.springframework.beans.factory.annotation.Autowired;
11import org.springframework.http.HttpStatus;
12import org.springframework.http.ResponseEntity;
13import org.springframework.web.bind.annotation.GetMapping;
14import org.springframework.web.bind.annotation.ResponseBody;
15import org.springframework.web.bind.annotation.RestController;
16
17import java.io.IOException;
18
19@RestController
20public class MainController {
21
22    private final Logger LOG = LoggerFactory.getLogger(getClass().getName());
23
24    private final CloseableHttpClient closeableHttpClient;
25    private CloseableHttpResponse closeableHttpResponse;
26
27    @Autowired
28    public MainController(CloseableHttpClient closeableHttpClient) {
29        this.closeableHttpClient = closeableHttpClient;
30    }
31
32    @GetMapping("/")
33    public @ResponseBody
34    ResponseEntity<String> hello() {
35        final String URI = "https://www.gremlin.com/";
36        HttpGet httpGet = new HttpGet(URI);
37        String responseContent = null;
38        long startTime = System.currentTimeMillis();
39        try {
40            LOG.info(String.format("Executing GET request to %s...", URI));
41            closeableHttpResponse = closeableHttpClient.execute(httpGet);
42            HttpEntity httpEntity = closeableHttpResponse.getEntity();
43            responseContent = EntityUtils.toString(httpEntity);
44            EntityUtils.consume(httpEntity);
45            LOG.info(responseContent);
46        } catch (IOException e) {
47            e.printStackTrace();
48        } finally {
49            long endTime = System.currentTimeMillis();
50            long duration = (endTime - startTime);
51            LOG.info(String.format("GET Request took %d milliseconds", duration));
52            try {
53                closeableHttpResponse.close();
54            } catch (IOException e) {
55                e.printStackTrace();
56            }
57        }
58        return new ResponseEntity<>(responseContent, HttpStatus.OK);
59    }
60}

Click here to create a new Attack
Fill out the Application Query and Traffic Query fields to match the following:

ALFI Core

This example uses Spring for Dependency Injection and the alfi-core jar.
Source code: https://github.com/gremlin/alfi-spring-boot

java

1package com.gremlin.todo.config;
2
3import com.gremlin.*;
4import com.gremlin.todo.ToDoApplication;
5import org.springframework.context.annotation.Bean;
6import org.springframework.stereotype.Service;
7
8import javax.annotation.PostConstruct;
9
10@Configuration
11public class ALFIConfig {
12
13    public GremlinCoordinatesProvider gremlinCoordinatesProvider() {
14        return new GremlinCoordinatesProvider() {
15            @Override
16            public ApplicationCoordinates initializeApplicationCoordinates() {
17                return new ApplicationCoordinates.Builder()
18                        .withType("MyApplication")
19                        .withField("service", "to-do")
20                        .build();
21            }
22        };
23    }
24    
25    public GremlinServiceFactory gremlinServiceFactory() {
26        return new GremlinServiceFactory(gremlinCoordinatesProvider());
27    }
28
29    @Bean
30    public GremlinService gremlinService() {
31        return gremlinServiceFactory().getGremlinService();
32    }
33    
34}

java

1package com.gremlin.todo.controller;
2
3import com.gremlin.todo.aspect.AdvancedAttack;
4import com.gremlin.todo.aspect.Attack;
5import com.gremlin.todo.dto.ToDoDto;
6import com.gremlin.todo.model.ToDo;
7import com.gremlin.todo.service.ToDoService;
8import org.bson.types.ObjectId;
9import org.springframework.beans.factory.annotation.Autowired;
10import org.springframework.http.HttpEntity;
11import org.springframework.http.HttpStatus;
12import org.springframework.http.ResponseEntity;
13import org.springframework.web.bind.annotation.*;
14
15import java.util.Collection;
16
17@RestController
18public class MyController {
19    private final GremlinService gremlinService;
20    private TrafficCoordinates getAllToDosCoordinates;
21    
22    @Autowired
23    public MyController(GremlinService gremlinService) {
24        this.gremlinService = gremlinService;
25    }
26
27    @GetMapping("/all")
28    public Collection<ToDo> getAllToDos() {
29        gremlinService.applyImpact(this.getAllToDosCoordinates);
30        return toDoService.findAll();
31    }
32
33    @PostConstruct() {
34        getAllToDosCoordinates = new TrafficCoordinates
35                                     .Builder()
36                                     .withType("MyController")
37                                     .withField("method", "getAllToDos")
38                                     .build();
39    }
40
41}

Click here to create a new Attack
Fill out the Application Query and Traffic Query fields to match the following:

The custom value for the traffic type is hidden behind elipses in that screenshot. The value is getAllToDos.

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