[OPIK-493] Fix Redis setup to properly config database indexes

apps/opik-backend/src/main/java/com/comet/opik/infrastructure/RedisConfig.java

@@ -1,5 +1,6 @@
 package com.comet.opik.infrastructure;
 
+import com.comet.opik.infrastructure.redis.RedisUrl;
 import com.comet.opik.utils.JsonUtils;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import jakarta.validation.Valid;
@@ -19,10 +20,13 @@ public class RedisConfig {
     public Config build() {
         Config config = new Config();
 
+        var redisUrl = RedisUrl.parse(singleNodeUrl);
+
         Objects.requireNonNull(singleNodeUrl, "singleNodeUrl must not be null");
 
         config.useSingleServer()
-                .setAddress(singleNodeUrl);
+                .setAddress(singleNodeUrl)
+                .setDatabase(redisUrl.database());
 
         config.setCodec(new JsonJacksonCodec(JsonUtils.MAPPER));
         return config;

apps/opik-backend/src/main/java/com/comet/opik/infrastructure/redis/RedisUrl.java

@@ -0,0 +1,36 @@
+package com.comet.opik.infrastructure.redis;
+
+import lombok.NonNull;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+public record RedisUrl(String scheme, String host, int port, int database) {
+
+    public static RedisUrl parse(@NonNull String redisUrl) {
+        try {
+            URI uri = new URI(redisUrl.trim());
+            String scheme = uri.getScheme();
+            String host = uri.getHost();
+            int port = uri.getPort() == -1 ? 6379 : uri.getPort();
+            String path = uri.getPath();
+            int database = 0;
+
+            if (path != null && path.length() > 1) {
+                database = getDatabase(path);
+            }
+
+            return new RedisUrl(scheme, host, port, database);
+        } catch (URISyntaxException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+
+    private static int getDatabase(String path) {
+        try {
+            return Integer.parseInt(path.substring(1));
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException("Invalid database index in Redis URL: " + path);
+        }
+    }
+}

apps/opik-backend/src/test/java/com/comet/opik/infrastructure/redis/RedisUrlTest.java

@@ -0,0 +1,40 @@
+package com.comet.opik.infrastructure.redis;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DisplayName("Redis URL parser Unit Test")
+class RedisUrlTest {
+
+    public static Stream<Arguments> testRedisUrlParser() {
+        return Stream.of(
+                Arguments.of("redis://localhost:6379/0", "redis", "localhost", 6379, 0),
+                Arguments.of("redis://localhost:6379/1", "redis", "localhost", 6379, 1),
+                Arguments.of("redis://localhost:6379", "redis", "localhost", 6379, 0),
+                Arguments.of("rediss://localhost:6379", "rediss", "localhost", 6379, 0),
+                Arguments.of("rediss://master.redis.cache.amazonaws.com:7000/3", "rediss",
+                        "master.redis.cache.amazonaws.com", 7000, 3),
+                Arguments.of("rediss://:xxxxxxxxxxx@redis-16379.hosted.com:16379/16", "rediss",
+                        "redis-16379.hosted.com", 16379, 16)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource
+    @DisplayName("Test parse method with different URLs")
+    void testRedisUrlParser(String url, String scheme, String host, int port, int database) {
+        var redisUrl = RedisUrl.parse(url);
+
+        assertThat(scheme).isEqualTo(redisUrl.scheme());
+        assertThat(host).isEqualTo(redisUrl.host());
+        assertThat(port).isEqualTo(redisUrl.port());
+        assertThat(database).isEqualTo(redisUrl.database());
+    }
+
+}