From 676bf0cf8b4b7390f12a9fdbfc8730117566456c Mon Sep 17 00:00:00 2001
From: Filipe Azevedo <filipe@azevedo.io>
Date: Fri, 2 Dec 2022 12:36:59 +0000
Subject: [PATCH] fail when ens rainbow not present

---
 graph/src/components/store/traits.rs |  2 ++
 runtime/wasm/src/host_exports.rs     |  4 +++
 runtime/wasm/src/module/mod.rs       |  6 ++++
 store/postgres/src/primary.rs        | 12 +++++++
 store/postgres/src/subgraph_store.rs | 52 +++++++++++++++++++++++++---
 5 files changed, 72 insertions(+), 4 deletions(-)

diff --git a/graph/src/components/store/traits.rs b/graph/src/components/store/traits.rs
index 4a0ccecb766..24d3918907e 100644
--- a/graph/src/components/store/traits.rs
+++ b/graph/src/components/store/traits.rs
@@ -32,6 +32,8 @@ pub trait EnsLookup: Send + Sync + 'static {
     /// Find the reverse of keccak256 for `hash` through looking it up in the
     /// rainbow table.
     fn find_name(&self, hash: &str) -> Result<Option<String>, StoreError>;
+    // Check if the rainbow table is filled.
+    fn is_table_empty(&self) -> Result<bool, StoreError>;
 }
 
 /// An entry point for all operations that require access to the node's storage
diff --git a/runtime/wasm/src/host_exports.rs b/runtime/wasm/src/host_exports.rs
index a412260fd32..d6eaf0d0f24 100644
--- a/runtime/wasm/src/host_exports.rs
+++ b/runtime/wasm/src/host_exports.rs
@@ -676,6 +676,10 @@ impl<C: Blockchain> HostExports<C> {
         Ok(self.ens_lookup.find_name(hash)?)
     }
 
+    pub(crate) fn is_ens_data_empty(&self) -> Result<bool, anyhow::Error> {
+        Ok(self.ens_lookup.is_table_empty()?)
+    }
+
     pub(crate) fn log_log(
         &self,
         logger: &Logger,
diff --git a/runtime/wasm/src/module/mod.rs b/runtime/wasm/src/module/mod.rs
index b4306e72b08..d7d473583a3 100644
--- a/runtime/wasm/src/module/mod.rs
+++ b/runtime/wasm/src/module/mod.rs
@@ -1689,6 +1689,12 @@ impl<C: Blockchain> WasmInstanceContext<C> {
 
         let hash: String = asc_get(self, hash_ptr, gas)?;
         let name = self.ctx.host_exports.ens_name_by_hash(&*hash)?;
+        if name.is_none() && self.ctx.host_exports.is_ens_data_empty()? {
+            return Err(anyhow!(
+                "Missing ENS data: see https://github.com/graphprotocol/ens-rainbow"
+            )
+            .into());
+        }
 
         // map `None` to `null`, and `Some(s)` to a runtime string
         name.map(|name| asc_new(self, &*name, gas).map_err(Into::into))
diff --git a/store/postgres/src/primary.rs b/store/postgres/src/primary.rs
index 80e45db241a..c4a01086667 100644
--- a/store/postgres/src/primary.rs
+++ b/store/postgres/src/primary.rs
@@ -1495,6 +1495,18 @@ impl<'a> Connection<'a> {
             .map_err(|e| anyhow!("error looking up ens_name for hash {}: {}", hash, e).into())
     }
 
+    pub fn is_ens_table_empty(&self) -> Result<bool, StoreError> {
+        use ens_names as dsl;
+
+        dsl::table
+            .select(dsl::name)
+            .limit(1)
+            .get_result::<String>(self.conn.as_ref())
+            .optional()
+            .map(|r| r.is_none())
+            .map_err(|e| anyhow!("error if ens table is empty: {}", e).into())
+    }
+
     pub fn record_active_copy(&self, src: &Site, dst: &Site) -> Result<(), StoreError> {
         use active_copies as cp;
 
diff --git a/store/postgres/src/subgraph_store.rs b/store/postgres/src/subgraph_store.rs
index 99cdab1fbae..04ef489658d 100644
--- a/store/postgres/src/subgraph_store.rs
+++ b/store/postgres/src/subgraph_store.rs
@@ -6,7 +6,7 @@ use diesel::{
 };
 use std::{
     collections::{BTreeMap, HashMap},
-    sync::{Arc, Mutex},
+    sync::{atomic::AtomicU8, Arc, Mutex},
 };
 use std::{fmt, io::Write};
 use std::{iter::FromIterator, time::Duration};
@@ -1147,8 +1147,35 @@ impl SubgraphStoreInner {
     }
 }
 
+const STATE_ENS_NOT_CHECKED: u8 = 0;
+const STATE_ENS_EMPTY: u8 = 1;
+const STATE_ENS_NOT_EMPTY: u8 = 2;
+
+/// EnsLookup reads from a rainbow table store in postgres that needs to be manually
+/// loaded. To avoid unnecessary database roundtrips, the empty table check is lazy
+/// and will not be retried. Once the table is checked, any subsequent calls will
+/// just used the stored result.
 struct EnsLookup {
     primary: ConnectionPool,
+    // In order to keep the struct lock free, we'll use u8 for the status:
+    // 0 - Not Checked
+    // 1 - Checked - empty
+    // 2 - Checked - non empty
+    state: AtomicU8,
+}
+
+impl EnsLookup {
+    pub fn new(pool: ConnectionPool) -> Self {
+        Self {
+            primary: pool,
+            state: AtomicU8::new(STATE_ENS_NOT_CHECKED),
+        }
+    }
+
+    fn is_table_empty(pool: &ConnectionPool) -> Result<bool, StoreError> {
+        let conn = pool.get()?;
+        primary::Connection::new(conn).is_ens_table_empty()
+    }
 }
 
 impl EnsLookupTrait for EnsLookup {
@@ -1156,14 +1183,31 @@ impl EnsLookupTrait for EnsLookup {
         let conn = self.primary.get()?;
         primary::Connection::new(conn).find_ens_name(hash)
     }
+
+    fn is_table_empty(&self) -> Result<bool, StoreError> {
+        match self.state.load(std::sync::atomic::Ordering::SeqCst) {
+            STATE_ENS_NOT_CHECKED => {}
+            STATE_ENS_EMPTY => return Ok(true),
+            STATE_ENS_NOT_EMPTY => return Ok(false),
+            _ => unreachable!("unsupported state"),
+        }
+
+        let is_empty = Self::is_table_empty(&self.primary)?;
+        let new_state = match is_empty {
+            true => STATE_ENS_EMPTY,
+            false => STATE_ENS_NOT_EMPTY,
+        };
+        self.state
+            .store(new_state, std::sync::atomic::Ordering::SeqCst);
+
+        Ok(is_empty)
+    }
 }
 
 #[async_trait::async_trait]
 impl SubgraphStoreTrait for SubgraphStore {
     fn ens_lookup(&self) -> Arc<dyn EnsLookupTrait> {
-        Arc::new(EnsLookup {
-            primary: self.mirror.primary().clone(),
-        })
+        Arc::new(EnsLookup::new(self.mirror.primary().clone()))
     }
 
     // FIXME: This method should not get a node_id