Add TimeIntervalFilter definition

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

RELEASE_NOTES.md

@@ -15,6 +15,7 @@
 - Added new message definitions for communication components.
 - Added new message `ElectricalComponentDiagnostic` to represent warnings and errors in microgrid electrical components.
 - The enum `ComponentErrorCode` has now been renamed to `ElectricalComponentDiagnosticCode` to better reflect its shared usage with warnings and errors.
+- Added a common `TimeIntervalFilter` message in `frequenz.api.common.v1.types` to standardize time interval filtering across APIs. This uses `start_time` (inclusive) and `end_time` (exclusive) fields, aligning with ISO 8601 and common programming conventions.
 
 ## Bug Fixes
 

proto/frequenz/api/common/v1/types/time_interval_filter.proto

@@ -0,0 +1,35 @@
+// An arbitrary precision real number.
+//
+// Copyright 2024 Frequenz Energy-as-a-Service GmbH
+//
+// Licensed under the MIT License (the "License");
+// you may not use this file except in compliance with the License.
+
+syntax = "proto3";
+
+package frequenz.api.common.v1.types;
+
+import "google/protobuf/timestamp.proto";
+
+
+// Represents a time interval filter.
+//
+// The interval includes the start time and excludes the end time.
+// This follows the convention used in ISO 8601 for time intervals,
+// Pandas slicing, and Python slicing: [start_time, end_time).
+//
+// * If `start_time` is omitted, the interval is
+//   considered unbounded at the start.
+// * If `end_time` is omitted, the interval is
+//   considered unbounded at the end.
+message TimeIntervalFilter {
+  // The beginning of the time interval (inclusive).
+  //
+  // Must be a UTC timestamp.
+  google.protobuf.Timestamp start_time = 1;
+
+  // The end of the time interval (exclusive).
+  //
+  // Must be a UTC timestamp.
+  google.protobuf.Timestamp end_time = 2;
+}