feat: Add blob size metrics (matter-labs#2411)

## What ❔

Add metrics for witness input data blob sizes

## Why ❔

To have deeper understanding of what is right and what is wrong

## Checklist

<!-- Check your PR fulfills the following items. -->
<!-- For draft PRs check the boxes as you complete them. -->

- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [x] Tests for the changes have been added / updated.
- [x] Documentation comments have been added / updated.
- [x] Code has been formatted via `zk fmt` and `zk lint`.

core/node/proof_data_handler/Cargo.toml

@@ -10,6 +10,7 @@ keywords.workspace = true
 categories.workspace = true
 
 [dependencies]
+vise.workspace = true
 zksync_config.workspace = true
 zksync_dal.workspace = true
 zksync_object_store.workspace = true

core/node/proof_data_handler/src/lib.rs

@@ -18,6 +18,7 @@ use zksync_types::commitment::L1BatchCommitmentMode;
 mod tests;
 
 mod errors;
+mod metrics;
 mod request_processor;
 mod tee_request_processor;
 

core/node/proof_data_handler/src/metrics.rs

@@ -0,0 +1,41 @@
+use vise::{Histogram, Metrics};
+use zksync_object_store::bincode;
+use zksync_prover_interface::inputs::WitnessInputData;
+
+const BYTES_IN_MEGABYTE: u64 = 1024 * 1024;
+
+#[derive(Debug, Metrics)]
+pub(super) struct ProofDataHandlerMetrics {
+    #[metrics(buckets = vise::Buckets::exponential(1.0..=2_048.0, 2.0))]
+    pub vm_run_data_blob_size_in_mb: Histogram<u64>,
+    #[metrics(buckets = vise::Buckets::exponential(1.0..=2_048.0, 2.0))]
+    pub merkle_paths_blob_size_in_mb: Histogram<u64>,
+    #[metrics(buckets = vise::Buckets::exponential(1.0..=2_048.0, 2.0))]
+    pub eip_4844_blob_size_in_mb: Histogram<u64>,
+    #[metrics(buckets = vise::Buckets::exponential(1.0..=2_048.0, 2.0))]
+    pub total_blob_size_in_mb: Histogram<u64>,
+}
+
+impl ProofDataHandlerMetrics {
+    pub fn observe_blob_sizes(&self, blob: &WitnessInputData) {
+        let vm_run_data_blob_size_in_mb =
+            bincode::serialize(&blob.vm_run_data).unwrap().len() as u64 / BYTES_IN_MEGABYTE;
+        let merkle_paths_blob_size_in_mb =
+            bincode::serialize(&blob.merkle_paths).unwrap().len() as u64 / BYTES_IN_MEGABYTE;
+        let eip_4844_blob_size_in_mb =
+            bincode::serialize(&blob.eip_4844_blobs).unwrap().len() as u64 / BYTES_IN_MEGABYTE;
+        let total_blob_size_in_mb =
+            bincode::serialize(blob).unwrap().len() as u64 / BYTES_IN_MEGABYTE;
+
+        self.vm_run_data_blob_size_in_mb
+            .observe(vm_run_data_blob_size_in_mb);
+        self.merkle_paths_blob_size_in_mb
+            .observe(merkle_paths_blob_size_in_mb);
+        self.eip_4844_blob_size_in_mb
+            .observe(eip_4844_blob_size_in_mb);
+        self.total_blob_size_in_mb.observe(total_blob_size_in_mb);
+    }
+}
+
+#[vise::register]
+pub(super) static METRICS: vise::Global<ProofDataHandlerMetrics> = vise::Global::new();

core/node/proof_data_handler/src/request_processor.rs

@@ -20,7 +20,7 @@ use zksync_types::{
     L1BatchNumber, H256,
 };
 
-use crate::errors::RequestProcessorError;
+use crate::{errors::RequestProcessorError, metrics::METRICS};
 
 #[derive(Clone)]
 pub(crate) struct RequestProcessor {
@@ -147,6 +147,8 @@ impl RequestProcessor {
             },
         };
 
+        METRICS.observe_blob_sizes(&blob);
+
         let proof_gen_data = ProofGenerationData {
             l1_batch_number,
             witness_input_data: blob,