[OPIK-6941] [BE] [FE] feat: workspace-level span metric aggregation in dashboards

apps/opik-backend/src/main/java/com/comet/opik/api/metrics/WorkspaceSpanMetricRequest.java

@@ -0,0 +1,42 @@
+package com.comet.opik.api.metrics;
+
+import com.comet.opik.api.TimeInterval;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
+import com.fasterxml.jackson.databind.annotation.JsonNaming;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.AssertTrue;
+import jakarta.validation.constraints.NotNull;
+import lombok.Builder;
+
+import java.time.Instant;
+import java.util.Optional;
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * Request for workspace-level span metrics aggregated across projects. When {@code projectIds} is empty, all projects
+ * in the workspace are included; otherwise only the given projects. {@code intervalEnd} is optional and defaults to
+ * "now" server-side, mirroring the per-project metrics endpoint.
+ */
+@Builder(toBuilder = true)
+@JsonIgnoreProperties(ignoreUnknown = true)
+@JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
+public record WorkspaceSpanMetricRequest(
+        Set<@NotNull UUID> projectIds,
+        MetricType metricType,
+        TimeInterval interval,
+        @Valid BreakdownConfig breakdown,
+        @NotNull Instant intervalStart,
+        Instant intervalEnd) {
+
+    @AssertTrue(message = "intervalStart must be before intervalEnd") public boolean isStartBeforeEnd() {
+        return intervalEnd == null || intervalStart.isBefore(intervalEnd);
+    }
+
+    public boolean hasBreakdown() {
+        return Optional.ofNullable(breakdown)
+                .map(BreakdownQueryBuilder::isEnabled)
+                .orElse(false);
+    }
+}

apps/opik-backend/src/main/java/com/comet/opik/api/resources/v1/priv/WorkspacesResource.java

@@ -8,6 +8,7 @@
 import com.comet.opik.api.metrics.WorkspaceMetricResponse;
 import com.comet.opik.api.metrics.WorkspaceMetricsSummaryRequest;
 import com.comet.opik.api.metrics.WorkspaceMetricsSummaryResponse;
+import com.comet.opik.api.metrics.WorkspaceSpanMetricRequest;
 import com.comet.opik.domain.WorkspaceConfigurationService;
 import com.comet.opik.domain.WorkspaceMetricsService;
 import com.comet.opik.domain.workspaces.WorkspaceVersionService;
@@ -150,6 +151,29 @@ public Response getCost(
         return Response.ok().entity(response).build();
     }
 
+    @POST
+    @Path("/metrics/spans")
+    @Operation(operationId = "getWorkspaceSpanMetric", summary = "Get workspace span metric", description = "Gets a span metric time series aggregated across the workspace. When project_ids is empty, all projects in the workspace are included; otherwise only the given projects.", responses = {
+            @ApiResponse(responseCode = "200", description = "Workspace span metric", content = @Content(schema = @Schema(implementation = WorkspaceMetricResponse.class))),
+            @ApiResponse(responseCode = "400", description = "Bad Request", content = @Content(schema = @Schema(implementation = ErrorMessage.class)))
+    })
+    @RequiredPermissions(WorkspaceUserPermission.PROJECT_DATA_VIEW)
+    public Response getWorkspaceSpanMetric(
+            @RequestBody(content = @Content(schema = @Schema(implementation = WorkspaceSpanMetricRequest.class))) @NotNull @Valid WorkspaceSpanMetricRequest request) {
+
+        String workspaceId = requestContext.get().getWorkspaceId();
+
+        log.info("Retrieve workspace span metric '{}' for projectIds '{}', on workspace_id '{}'", request.metricType(),
+                request.projectIds(), workspaceId);
+        WorkspaceMetricResponse response = workspaceMetricsService.getWorkspaceSpanMetric(request)
+                .contextWrite(ctx -> setRequestContext(ctx, requestContext))
+                .block();
+        log.info("Retrieved workspace span metric '{}' for projectIds '{}', on workspace_id '{}'", request.metricType(),
+                request.projectIds(), workspaceId);
+
+        return Response.ok().entity(response).build();
+    }
+
     @GET
     @Path("/versions")
     @Operation(operationId = "getWorkspaceVersion", summary = "Get workspace version", description = """