Added differential signer state sync

libs/gl-client/src/lib.rs

@@ -29,6 +29,7 @@ pub mod scheduler;
 pub mod signer;
 
 pub mod persist;
+pub mod metrics;
 
 pub mod lnurl;
 

libs/gl-client/src/metrics.rs

@@ -0,0 +1,43 @@
+use prost::Message;
+
+const HSM_REQUEST_SIGNER_STATE_FIELD_NUMBER: u32 = 4;
+const HSM_RESPONSE_SIGNER_STATE_FIELD_NUMBER: u32 = 5;
+
+fn protobuf_varint_len(mut value: usize) -> usize {
+    let mut len = 1;
+    while value >= 0x80 {
+        value >>= 7;
+        len += 1;
+    }
+    len
+}
+
+fn signer_state_wire_bytes(entries: &[crate::pb::SignerStateEntry], field_number: u32) -> usize {
+    let field_key = ((field_number << 3) | 2) as usize; // wire type 2 = length-delimited
+    let field_key_len = protobuf_varint_len(field_key);
+    entries
+        .iter()
+        .map(|entry| {
+            let entry_len = entry.encoded_len();
+            field_key_len + protobuf_varint_len(entry_len) + entry_len
+        })
+        .sum()
+}
+
+pub fn signer_state_request_wire_bytes(entries: &[crate::pb::SignerStateEntry]) -> usize {
+    signer_state_wire_bytes(entries, HSM_REQUEST_SIGNER_STATE_FIELD_NUMBER)
+}
+
+pub fn signer_state_response_wire_bytes(entries: &[crate::pb::SignerStateEntry]) -> usize {
+    signer_state_wire_bytes(entries, HSM_RESPONSE_SIGNER_STATE_FIELD_NUMBER)
+}
+
+pub fn savings_percent(full_wire_bytes: usize, diff_wire_bytes: usize) -> usize {
+    if full_wire_bytes == 0 {
+        return 0;
+    }
+    full_wire_bytes
+        .saturating_sub(diff_wire_bytes)
+        .saturating_mul(100)
+        / full_wire_bytes
+}