Merge pull request #15637 from imsurajmishra/bael-7192

implementation for bael-7192

spring-boot-modules/spring-boot-logging-loki/README.md

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+### Relevant Articles:

spring-boot-modules/spring-boot-logging-loki/pom.xml

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+<?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>
+    <artifactId>spring-boot-logging-loki</artifactId>
+    <version>0.1-SNAPSHOT</version>
+    <name>loki</name>
+
+    <parent>
+        <groupId>com.baeldung.spring-boot-modules</groupId>
+        <artifactId>spring-boot-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.github.loki4j</groupId>
+            <artifactId>loki-logback-appender</artifactId>
+            <version>${loki-logback.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <loki-logback.version>1.4.2</loki-logback.version>
+    </properties>
+</project>

spring-boot-modules/spring-boot-logging-loki/src/main/java/com/baeldung/loki/DemoService.java

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+package com.baeldung.loki;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Service;
+
+@Service
+public class DemoService {
+
+    private static final Logger LOG = LoggerFactory.getLogger(DemoService.class);
+
+    public void log() {
+        LOG.info("DemoService.log invoked");
+    }
+}

spring-boot-modules/spring-boot-logging-loki/src/main/resources/logback-spring.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+
+    <springProperty name="name" source="spring.application.name"/>
+    <appender name="LOKI" class="com.github.loki4j.logback.Loki4jAppender">
+        <http>
+            <url>http://localhost:3100/loki/api/v1/push</url>
+        </http>
+        <format>
+            <label>
+                <pattern>app=${name},host=${HOSTNAME},level=%level</pattern>
+                <readMarkers>true</readMarkers>
+            </label>
+            <message>
+                <pattern>
+                    {
+                    "level":"%level",
+                    "class":"%logger{36}",
+                    "thread":"%thread",
+                    "message": "%message",
+                    "requestId": "%X{X-Request-ID}"
+                    }
+                </pattern>
+            </message>
+        </format>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="LOKI"/>
+    </root>
+
+</configuration>

spring-boot-modules/spring-boot-logging-loki/src/test/java/com/baeldung/loki/DemoServiceLiveTest.java

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+package com.baeldung.loki;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.net.URI;
+import java.time.LocalDateTime;
+import java.time.ZoneOffset;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.util.UriComponentsBuilder;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+@SpringBootTest(classes = DemoService.class)
+public class DemoServiceLiveTest {
+
+    /**
+     * This test assumes that loki service is already up.
+     * For more details please check section #2 Running Loki and Grafana Service
+     * Which spin up Loki server using docker-compose
+     */
+    @Test
+    public void givenLokiContainerRunning_whenDemoServiceInvoked_thenLokiAppenderCollectLogs() throws JsonProcessingException, InterruptedException {
+        DemoService service = new DemoService();
+        service.log();
+
+        String baseUrl = "http://localhost:3100/loki/api/v1/query_range";
+        // Set up query parameters
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.APPLICATION_JSON);
+        String query = "{level=\"INFO\"} |= `DemoService.log invoked`";
+
+        // Get current time in UTC
+        LocalDateTime currentDateTime = LocalDateTime.now(ZoneOffset.UTC);
+        String currentTimeUtc = currentDateTime.format(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'"));
+
+        LocalDateTime tenMinsAgo = currentDateTime.minusMinutes(10);
+        String startTimeUtc = tenMinsAgo.format(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'"));
+
+        URI uri = UriComponentsBuilder.fromUriString(baseUrl)
+            .queryParam("query", query)
+            .queryParam("start", startTimeUtc)
+            .queryParam("end", currentTimeUtc)
+            .build()
+            .toUri();
+
+        RestTemplate restTemplate = new RestTemplate();
+        ResponseEntity<String> response = restTemplate.exchange(uri, HttpMethod.GET, new HttpEntity<>(headers), String.class);
+
+        List<String> messages = new ArrayList<>();
+        ObjectMapper objectMapper = new ObjectMapper();
+        assertEquals(response.getStatusCode(), HttpStatus.OK);
+
+        String responseBody = response.getBody();
+        JsonNode jsonNode = objectMapper.readTree(responseBody);
+        JsonNode result = jsonNode.get("data")
+            .get("result")
+            .get(0)
+            .get("values");
+        result.iterator()
+            .forEachRemaining(e -> {
+                Iterator<JsonNode> elements = e.elements();
+                elements.forEachRemaining(f -> messages.add(f.toString()));
+            });
+
+        String expected = "DemoService.log invoked";
+        assertThat(messages).anyMatch(e -> e.contains(expected));
+    }
+}