From 1063e245c829cda7c3292814dfc9cee85b47e135 Mon Sep 17 00:00:00 2001
From: Matthew Cantelon <gh@matthewcantelon.ca>
Date: Thu, 10 Jun 2021 07:19:20 -0700
Subject: [PATCH] feat: least surprise in failures

This change covers two possible failures:

* a developer requesting a chain that hasn't been configured
* network failures on subgraphs

If a developer forgets to add to the client map, this will throw an
error instead of defaulting to ethereum results. This helps the
developer make changes correctly.

If a network failure occurs or a developer makes a mistake, the entire
membership structure is not affected via `Promise.allSettled`. This avoids
confusing errors for users.
---
 .../remote-schemas/resolvers/daohaus/resolver.ts   | 14 +++++++++-----
 packages/backend/src/lib/daoHausClient.ts          | 11 ++++++++---
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/packages/backend/src/handlers/remote-schemas/resolvers/daohaus/resolver.ts b/packages/backend/src/handlers/remote-schemas/resolvers/daohaus/resolver.ts
index f45d3f95..295802e0 100644
--- a/packages/backend/src/handlers/remote-schemas/resolvers/daohaus/resolver.ts
+++ b/packages/backend/src/handlers/remote-schemas/resolvers/daohaus/resolver.ts
@@ -26,16 +26,20 @@ export const getDaoHausMemberships: QueryResolvers['getDaoHausMemberships'] = as
 
   const membershipsOn = addChain(memberAddress);
 
-  const memberships = await Promise.all([
+  const memberships = await Promise.allSettled([
     membershipsOn('ethereum'),
     membershipsOn('polygon'),
     membershipsOn('xdai'),
   ]);
 
-  const members: Member[] = memberships.reduce(
-    (allMembers, chainMembers) => [...allMembers, ...chainMembers],
-    <Member[]>[],
-  );
+  const members: Member[] = memberships.reduce((allMembers, chainMembers) => {
+    if (chainMembers.status === 'rejected') {
+      console.error('Pulling memberships failed:', chainMembers.reason);
+      return allMembers;
+    }
+
+    return [...allMembers, ...chainMembers.value];
+  }, <Member[]>[]);
 
   return members;
 };
diff --git a/packages/backend/src/lib/daoHausClient.ts b/packages/backend/src/lib/daoHausClient.ts
index 8ebd1b8a..e48e6ba3 100644
--- a/packages/backend/src/lib/daoHausClient.ts
+++ b/packages/backend/src/lib/daoHausClient.ts
@@ -3,13 +3,18 @@ import { GraphQLClient } from 'graphql-request';
 import { CONFIG } from '../config';
 import { getSdk, Sdk } from './autogen/daohaus-sdk';
 
-const defaultGqlClient = new GraphQLClient(CONFIG.daoHausGraphqlURL);
 const clients = new Map([
   ['polygon', new GraphQLClient(CONFIG.daoHausPolygonGraphqlURL)],
   ['xdai', new GraphQLClient(CONFIG.daoHausXdaiGraphqlURL)],
-  ['ethereum', defaultGqlClient],
+  ['ethereum', new GraphQLClient(CONFIG.daoHausGraphqlURL)],
 ]);
 
 export function getClient(chain: string): Sdk {
-  return getSdk(clients.get(chain) || defaultGqlClient);
+  const gqlClient = clients.get(chain);
+  if (!gqlClient)
+    throw new Error(
+      `The '${chain}' chain is unrecognized, unable to create GQL Client`,
+    );
+
+  return getSdk(gqlClient);
 }