basic programming
Sometimes we want to create a symlink on our code and push it to Git repository. For Linux or MacOS system, it is quite straightforward. However things are different in Windows 10, which we can use below command
$ mklink new.txt old.txt
Sample git repo with symlink file can be found in below URL,
https://github.com/edwin/symlinks-on-windows-and-git
Basically we can create a folder to store JBoss EAP logs with hostname as its name. We can leverage “jboss.node.name” variable for this.
<periodic-rotating-file-handler name="FILE" autoflush="true">
<formatter>
<named-formatter name="PATTERN"/>
</formatter>
<file path="/log/${jboss.node.name}/server.log"/>
<suffix value=".yyyy-MM-dd"/>
<append value="true"/>
</periodic-rotating-file-handler>
There are times where we want to build our application while pointing our library to a specific custom folder, which is having a relative folder location to current project Java folder.
For example, i have a Java project and a Libs folder with structure like below
libs/ +--- org | +--- postgresql | | +--- postgresql | | | +--- random.version | | | | +--- postgresql-random.version.jar java_project/ +--- pom.xml +--- src | +--- main | | +--- java
We can build our java_project by refering to libs folder by using this configuration on our pom.xml
<repositories>
<repository>
<id>local-repo</id>
<name>Local Repository</name>
<url>file://${project.basedir}/../libs</url>
</repository>
</repositories>
And refer it
<dependency> <groupId>org.postgresql</groupId> <artifactId>postgresql</artifactId> <version>random.version</version> </dependency>
Running maven build command will display the complete build log where library is coming from our relative folder location,
$ mvn clean package ....... Downloading from local-repo: file:///source/java_project/../libs/org/postgresql/postgresql/random.version/postgresql-random.version.jar [WARNING] Could not validate integrity of download from file:///source/java_project/../libs/org/postgresql/postgresql/random.version/postgresql-random.version.jar: Checksum validation failed, no checksums available [WARNING] Checksum validation failed, no checksums available from local-repo for file:///source/java_project/../libs/org/postgresql/postgresql/random.version/postgresql-random.version.jar Downloaded from local-repo: file:///source/java_project/../libs/org/postgresql/postgresql/random.version/postgresql-random.version.jar (1.0 MB at 7.0 MB/s)
Distributed Tracing with Spring Boot, Infinispan, and Jaeger
Infinispan 14, or Datagrid 8.4, has the capability to implement a distributed tracing which will make distributed tracing easier and providing a better end-to-end view.
The concept of distributed tracing perhaps looks like this,
For this example, we are going to use Spring Boot 3 and OpenTelemetry for client side, and Jaeger all-in-one on for monitoring. So lets start with a simple pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.edw</groupId>
<artifactId>spring-boot-infinispan-and-jaeger</artifactId>
<version>1.0</version>
<name>Spring Boot 3 with OpenTelemetry and Jaeger</name>
<description>Spring Boot testing app with opentelemetry</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.0.5</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<version.infinispan>14.0.2.Final</version.infinispan>
<version.protostream>4.6.2.Final</version.protostream>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-bom</artifactId>
<version>${version.infinispan}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- tracing -->
<dependency>
<groupId>io.micrometer</groupId>
<artifactId>micrometer-tracing-bridge-otel</artifactId>
</dependency>
<dependency>
<groupId>io.opentelemetry</groupId>
<artifactId>opentelemetry-exporter-otlp</artifactId>
</dependency>
<!-- infinispan -->
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-spring-boot-starter-remote</artifactId>
</dependency>
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-query</artifactId>
</dependency>
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-remote-query-client</artifactId>
</dependency>
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-api</artifactId>
</dependency>
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-spring-boot-starter-embedded</artifactId>
</dependency>
<dependency>
<groupId>org.infinispan.protostream</groupId>
<artifactId>protostream-processor</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.infinispan</groupId>
<artifactId>infinispan-client-hotrod</artifactId>
</dependency>
<dependency>
<groupId>javax.transaction</groupId>
<artifactId>jta</artifactId>
<version>1.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Next is some Java classes,
@SpringBootApplication
public class Main {
public static void main(String[] args) {
SpringApplication.run(Main.class, args);
}
}
@RestController
public class IndexController {
private static final Logger logger = LoggerFactory.getLogger(IndexController.class);
@Autowired
private IndexService indexService;
@GetMapping("/")
public ResponseEntity path1() {
logger.info("request at / ");
indexService.createData();
return ResponseEntity.ok().build();
}
}
@Service
public class IndexService {
@Autowired
private RemoteCacheManager cacheManager;
@Autowired
private Tracer tracer;
private Logger logger = LoggerFactory.getLogger(this.getClass());
public void createData() {
logger.info("starting ====================");
// starting span
Span span = tracer.spanBuilder()
.name("cache-add")
.tag("cache", "balance")
.kind(Span.Kind.CLIENT).start();
final RemoteCache cache = cacheManager.getCache("balance");
// generate cache key
String key = UUID.randomUUID().toString();
// put it
cache.put(key, Math.random());
// get it -- somehow this is not monitored in Jaeger
Double value = Double.parseDouble((String)cache.get(key));
// and remove it
cache.remove(key);
span.end();
logger.info("done processing {} - {} ====================", key, value);
}
}
@Configuration
public class OtlpConfiguration {
@Bean
public OtlpHttpSpanExporter otlpHttpSpanExporter() {
return OtlpHttpSpanExporter.builder()
.build();
}
}
@Configuration
public class InfinispanConfiguration {
@Bean
public RemoteCacheManager remoteCacheManager() {
return new RemoteCacheManager(
new org.infinispan.client.hotrod.configuration.ConfigurationBuilder()
.addServers("127.0.0.1:11222")
.security().authentication().username("admin").password("password")
.clientIntelligence(ClientIntelligence.HASH_DISTRIBUTION_AWARE)
.marshaller(ProtoStreamMarshaller.class)
.build());
}
}
server.port=8080
spring.application.name=app-testing
management.tracing.sampling.probability=1.0
management.otlp.metrics.export.url=http://localhost:4318/v1/traces
management.otlp.metrics.export.step=5s
logging.pattern.level=%5p [${spring.application.name:},%X{traceId:-},%X{spanId:-}]
Once we have all Java classes ready, we’ll continue with setting Jaeger server up. We’ll need
docker run -d \
-e COLLECTOR_OTLP_ENABLED=true \
-p 16686:16686 \
-p 4317:4317 \
-p 4318:4318 \
jaegertracing/all-in-one:1.40
Next is setting up our Infinispan cache,
<distributed-cache name="balance" mode="SYNC" remote-timeout="30000" statistics="true">
<encoding media-type="text/plain"/>
<locking concurrency-level="1000" isolation="READ_COMMITTED" acquire-timeout="60000" striping="false"/>
<transaction mode="NON_XA" auto-commit="true" stop-timeout="30000" locking="PESSIMISTIC" reaper-interval="30000" complete-timeout="30000" notifications="true"/>
<state-transfer timeout="30000"/>
</distributed-cache>
And dont forget to put this Java runtime variables on our Infinispan,
JAVA_OPTS="$JAVA_OPTS -Dinfinispan.tracing.enabled=true -Dotel.service.name=infinispan-server
-Dotel.exporter.otlp.endpoint=http://localhost:4317 -Dotel.metrics.exporter=none"
We can run this app, and see the result on our Jaeger dashboard.
And this is the detail traces within one same request,
Code for this article can be found on below Github link
https://github.com/edwin/spring-boot-infinispan-and-jaeger
Have fun.
Sometimes we need to measure how long does a java process or a specific method take. We can use some traditional method like below to do that but it wont be too elegant
private void someMethod() {
Long timestamp = System.currentTimeMillis();
// do some process
logger.info(System.currentTimeMillis()-timestamp)
}
It looks good but we are unable to generate a report or statistics for this. And this is where Java Melody’s Stopwatch comes into the picture. It can measure the time needed for a specific process and generate report and statistics for it.
This is how it works,
public class RestService {
public void callRestAPIOne() {
try (Stopwatch stopwatch = new Stopwatch("stopwatch-for-one-todo")) {
try {
HttpRequest request = HttpRequest.newBuilder().uri(new URI("https://jsonplaceholder.typicode.com/todos/1"))
.GET().build();
System.out.println(HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString()).body());
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
public void callRestAPITwo() {
try (Stopwatch stopwatch = new Stopwatch("stopwatch-for-users")) {
try {
HttpRequest request = HttpRequest.newBuilder().uri(new URI("https://jsonplaceholder.typicode.com/users"))
.GET().build();
System.out.println(HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString()).body());
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
public void callRestAPIThree() {
try (Stopwatch stopwatch = new Stopwatch("stopwatch-for-posts")) {
try {
HttpRequest request = HttpRequest.newBuilder().uri(new URI("https://jsonplaceholder.typicode.com/posts"))
.GET().build();
System.out.println(HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString()).body());
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
And it shall generate report like this,
