Adding implementation for subscription manager This CL introduces the implementation of subscription manager and related classes. It includes the following features: - ResourceMonitor to monitor the sampling intervals for each resource. - ActiveSubscription to manage a single subscription. - SubscriptionManagerImpl which provide APIs to add/remove subscriptions. - Resample function which downsample data collected by the data source. - Unit tests to validate the implementation. In addition to above changes, added `SubscriptionPolicy` to SubscriptionParams to allow the subscriber to specify Resource to subscribe and whether subscription should apply to all resources or specific based on the given identifiers Tested: Unit Test #tlbmc #tlbmc-hft PiperOrigin-RevId: 760813662 Change-Id: I78f76b4ea6dcd6cfb07ff3489cbee4be38c7d53d

diff --git a/tlbmc/sensor_payload.proto b/tlbmc/sensor_payload.proto
index c1aace3..00a84f1 100644
--- a/tlbmc/sensor_payload.proto
+++ b/tlbmc/sensor_payload.proto

@@ -5,7 +5,10 @@
 import "sensor_identifier.proto";
 
 message HighFrequencySensorReading {
-  float float_reading = 1;
+  oneof reading {
+    float float_reading = 1;
+    // Add support for other types of readings.
+  }
   int64 timestamp_ns = 2;  // Nanosecond timestamp of the readings.
 }
 
@@ -15,5 +18,5 @@
 }
 
 message HighFrequencySensorsReadingsBatch {
-  repeated HighFrequencySensorsReadings readings = 1;
+  repeated HighFrequencySensorsReadings high_frequency_sensors = 1;
 }

diff --git a/tlbmc/subscription/manager.h b/tlbmc/subscription/manager.h
index 3d30b86..092d4c2 100644
--- a/tlbmc/subscription/manager.h
+++ b/tlbmc/subscription/manager.h

@@ -1,43 +1,29 @@
 #ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_HFT_SUBSCRIPTION_MANAGER_H_
 #define THIRD_PARTY_MILOTIC_EXTERNAL_CC_HFT_SUBSCRIPTION_MANAGER_H_
 
-#include <memory>
+#include <string>
 
 #include "absl/functional/any_invocable.h"
-#include "tlbmc/adapter/data_source.h"
-#include "tlbmc/subscription/store.h"
+#include "absl/status/status.h"
+#include "absl/status/statusor.h"
 #include "tlbmc/types/payload.proto.h"
 #include "tlbmc/types/subscription_params.proto.h"
-#include "tlbmc/scheduler/scheduler.h"
 
 namespace milotic_hft {
 
 class SubscriptionManager {
  public:
-  // A handle to a subscription that can be used to cancel the subscription.
-  class SubscriptionHandle {
-   public:
-    ~SubscriptionHandle() { subscription_->Cancel(); }
-
-   private:
-    Subscription* subscription_;
-  };
+  using SubscriptionId = std::string;
 
   virtual ~SubscriptionManager() = default;
 
   // Adds a new subscription to the manager.
   // `on_data_callback` will be called when new data is available to be exported
   // to the subscriber.
-  virtual void AddSubscription(
+  virtual absl::StatusOr<SubscriptionId> AddSubscription(
       const SubscriptionParams& params,
-      absl::AnyInvocable<void(Payload&&)>
-          on_data_callback) = 0;
-
- private:
-  // An adapter to the data source.
-  std::unique_ptr<DataSource> data_source_;
-  std::unique_ptr<SubscriptionStore> subscription_store_;
-  std::unique_ptr<milotic_tlbmc::TaskScheduler> task_scheduler_;
+      absl::AnyInvocable<void(Payload&&)> on_data_callback) = 0;
+  virtual absl::Status Unsubscribe(const SubscriptionId& sub_id) = 0;
 };
 
 }  // namespace milotic_hft

diff --git a/tlbmc/subscription_params.proto b/tlbmc/subscription_params.proto
index 5fdaa1c..84b3a98 100644
--- a/tlbmc/subscription_params.proto
+++ b/tlbmc/subscription_params.proto

@@ -4,6 +4,22 @@
 
 import "identifier.proto";
 
+message SubscriptionPolicy {
+  enum ConfigurationType {
+    CONFIGURATION_TYPE_UNSPECIFIED = 0;
+    CONFIGURATION_TYPE_CONFIGURE_ALL_RESOURCES = 1;
+    CONFIGURATION_TYPE_CONFIGURE_SPECIFIC_RESOURCES = 2;
+  }
+
+  enum ResourceType {
+    RESOURCE_TYPE_UNSPECIFIED = 0;
+    RESOURCE_TYPE_SENSOR = 1;
+    RESOURCE_TYPE_FRU = 2;
+  }
+  ConfigurationType configuration_type = 1;
+  ResourceType resource_type = 2;
+}
+
 message SubscriptionParams {
   // The interval between two consecutive batches of readings.
   // If not set, the default sampling interval is implementation defined.
@@ -23,10 +39,10 @@
   int32 export_interval_ms = 2;
 
   // The number of batches to export before cancelling the subscription.
-  // If set to 0, the subscription will remain active indefinitely.
-  // If not set, the subscription will be cancelled after the first batch.
-  int32 num_batches = 3 [default = 1];
+  // If not set, the subscription will continue until explicitly cancelled.
+  int32 num_batches = 3;
 
-  // The identifier of the data source to subscribe to.
-  Identifier identifier = 4;
+  // The identifiers of the resources to subscribe to.
+  repeated Identifier identifiers = 4;
+  SubscriptionPolicy subscription_policy = 5;
 }