refactor(migrate-from-gcs): split in mods

Splits the blob of proven code into neat modules.

src/bin/migrate-from-gcs/execution_payloads.rs

@@ -0,0 +1,64 @@
+use std::fmt;
+
+use csv::ByteRecord;
+use serde::Serialize;
+
+use crate::slots::Slot;
+
+#[derive(Serialize)]
+pub struct ExecutionPayload {
+    block_hash: String,
+    #[serde(skip_serializing)]
+    id: String,
+    inserted_at: String,
+    payload: serde_json::Value,
+    proposer_pubkey: String,
+    slot: Slot,
+    version: String,
+}
+
+impl ExecutionPayload {
+    pub fn payload_block_hash(&self) -> &str {
+        self.payload["block_hash"].as_str().unwrap()
+    }
+
+    pub fn slot(&self) -> Slot {
+        self.slot
+    }
+}
+
+impl fmt::Debug for ExecutionPayload {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let payload_block_hash = self.payload_block_hash();
+        f.debug_struct("ExecutionPayload")
+            .field("block_hash", &self.block_hash)
+            .field("id", &self.id)
+            .field("inserted_at", &self.inserted_at)
+            .field("proposer_pubkey", &self.proposer_pubkey)
+            .field("slot", &self.slot)
+            .field("version", &self.version)
+            .field(
+                "payload",
+                &format!("<PAYLOAD block_hash={}>", payload_block_hash),
+            )
+            .finish()
+    }
+}
+
+impl From<ByteRecord> for ExecutionPayload {
+    fn from(value: ByteRecord) -> Self {
+        Self {
+            block_hash: String::from_utf8(value[4].into()).unwrap(),
+            id: String::from_utf8(value[0].into()).unwrap(),
+            inserted_at: String::from_utf8(value[1].into()).unwrap(),
+            payload: serde_json::from_slice(&value[6]).unwrap(),
+            proposer_pubkey: String::from_utf8(value[3].into()).unwrap(),
+            slot: std::str::from_utf8(&value[2])
+                .unwrap()
+                .parse()
+                .map(Slot)
+                .unwrap(),
+            version: String::from_utf8(value[5].into()).unwrap(),
+        }
+    }
+}