FsdbSyncManager gflag to enable patch publish

Summary:
In FsdbSyncManager introduce gflag fsdb_publish_state_with_patches which can be
set by client binaries to enable publishing state to FSDB using patches instead
of deltas.

Differential Revision: D75021159

fbshipit-source-id: 8e1611007a253f60fa6116e6e0e9c7eaf5d9bf51

Author: Priyank Warkhede

fboss/fsdb/client/FsdbSyncManager.cpp

@@ -7,4 +7,16 @@ DEFINE_bool(
     false,
     "Publish paths using thrift ids rather than names");
 
-namespace facebook::fboss::fsdb {} // namespace facebook::fboss::fsdb
+DEFINE_bool(
+    fsdb_publish_state_with_patches,
+    false,
+    "Publish state to FSDB using Patches instead of Deltas, default false");
+
+namespace facebook::fboss::fsdb {
+
+PubSubType getFsdbStatePubType() {
+  return FLAGS_fsdb_publish_state_with_patches ? PubSubType::PATCH
+                                               : PubSubType::DELTA;
+}
+
+} // namespace facebook::fboss::fsdb

fboss/fsdb/client/FsdbSyncManager.h

@@ -17,8 +17,12 @@
 
 DECLARE_bool(publish_use_id_paths);
 
+DECLARE_bool(fsdb_publish_state_with_patches);
+
 namespace facebook::fboss::fsdb {
 
+PubSubType getFsdbStatePubType();
+
 template <typename PubRootT, bool EnablePatchAPIs = false>
 class FsdbSyncManager {
  public: