Spring Boot Actuator

Actuator is mainly used to expose operational information about the running application — health, metrics, info, dump, env, etc. It uses HTTP endpoints or JMX beans to enable us to interact with it.

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency>

management.endpoints.web.exposure.include=*

List of endpoints (More than 15 endpoints)



Here are some of the most common endpoints Boot provides out of the box:

  • /health shows application health information (a simple status when accessed over an unauthenticated connection or full message details when authenticated); it's not sensitive by default.
  • /info displays arbitrary application info; it's not sensitive by default.
  • /metrics shows metrics information for the current application; it's sensitive by default.
  • /trace displays trace information (by default the last few HTTP requests).








Custom Health Indicator

We need to extend this class and override the doHealthCheck() method.

public abstract class AbstractHealthIndicator implements HealthIndicator {
    private static final String NO_MESSAGE = null;
    private static final String DEFAULT_MESSAGE = "Health check failed";
    private final Log logger;
    private final Function<Exception, String> healthCheckFailedMessage;

    protected AbstractHealthIndicator() {
        this(NO_MESSAGE);
    }

    protected AbstractHealthIndicator(Function<Exception, String> healthCheckFailedMessage) {
        this.logger = LogFactory.getLog(this.getClass());
        Assert.notNull(healthCheckFailedMessage, "HealthCheckFailedMessage must not be null");
        this.healthCheckFailedMessage = healthCheckFailedMessage;
    }

    public final Health health() {
        Builder builder = new Builder();
        try {
            this.doHealthCheck(builder);
        } catch (Exception var3) {
            builder.down(var3);
        }

        this.logExceptionIfPresent(builder.getException());
        return builder.build();
    }

    protected abstract void doHealthCheck(Builder builder) throws Exception;
}

Sample

public class DatabaseHealthIndicator extends AbstractHealthIndicator {

    private static final Logger LOG = LoggerFactory.getLogger(DatabaseHealthIndicator.class);

    @Autowired
    private DataSource dataSource;

    /**
     * @param builder : health check
     * Overriding custom health check to check either database is UP / DOWN
     */
    @Override
    protected void doHealthCheck(Health.Builder builder) throws SQLException {
        try {
            boolean check = checkDatabase();
            if (check) {
                // The database is UP
                builder.up();
                return;
            }
            LOG.warn("Database is down");
            //The database is DOWN => give some details
            builder.down().withDetail("error", "Connection timed out").withDetail("message", "Unable to connect to database");
        } catch (Exception e) {
            LOG.error("Unknown error {}", e.toString());
            // Unable to fetch the status of the module => Set the status to UNKNOWN and give some details
            builder.unknown().withDetail("error", e.toString()).withDetail("message", "Database is down.");
        }
    }
    //This method ensures if we are able to establish connection with database or not
    private boolean checkDatabase() throws SQLException {
        try (Connection connection = dataSource.getConnection()) {
            return true;
        } catch (SQLException exe) {
            return false;
        }
    }







































Comments

Post a Comment

Popular posts from this blog

Java 8 : Find the number starts with 1 from a list of integers

  List<Integer> list = List. of ( 12 , 32 , 14 , 15 , 56 ); //Result->12,14,15 List<String> listString = list.stream().map(String::valueOf).collect(Collectors.toList()); List<String> result1 = listString.stream().filter(x->x.startsWith( "1" )) .collect(Collectors.toList()); System. out .println( "result1-->" +result1); List<String> result2 = list.stream().map(x->x+ "" ).filter(x->x.startsWith( "1" )) .collect(Collectors.toList()); System. out .println( "result2-->" +result2);
Read more

Junit Mockito and Power Mockito

Mock vs Spy Both can be used to mock methods or fields. The difference is that  in mock, you are creating a complete mock or fake object while in spy, there is the real object and you just spying or stubbing specific methods of it . Mock vs InjectMock @Mock  creates a mock.  @InjectMocks  creates an instance of the class and injects the mocks that are created with the  @Mock  (or  @Spy ) annotations into this instance. Unit Testing Void Methods with Mockito and JUnit How to Test Void Methods  As we already know that our aim is to test void methods in a class. But it is also really important to understand why we test void methods.  Whenever we write unit test cases for any method, we expect a return value from the method. Generally, we use assert for checking if the method returns the value that we expect it to return, but in the case of void methods, they do not return any value. So how do we check if our method is functioning properly? Let’s...
Read more

Important Linux Commands

  ls -lrt → command lists the contents of the directory with all the details, in reverse order of their modification time (older files will be displayed first) ls -lrth → This will list the contents of the current directory showing more information and sorting them so the most recently modified file will be displayed last. The h flag makes the file sizes more human friendly! chmod 755 <name> → chmod 755 sets the 755 permission for a file. 755 means full permissions for the owner and read and execute permission for others. ln -s 14.9.0-SNAPSHOT current → Create a current tag and mapped to current version. To link files in the same directory Update Any File → sed -i 's/10.46.87.148/10.46.87.115/g' journal.sch textToFind → 10.46.87.148 replaceText → 10.46.87.115 FileName → journal.sch . SED is a text stream editor used on Unix systems to edit files quickly and efficiently Untar a tar file → tar -xvzf filename.tar Rmove a folder → rm -r folderName netstat -anpe | grep ...
Read more