update queue sharding so that it can be rebalanced using a seed (#198)

app/reports/page-content.tsx

@@ -13,6 +13,7 @@ import {
   ToolsOzoneModerationDefs,
   ToolsOzoneModerationEmitEvent,
   ToolsOzoneModerationQueryStatuses,
+  ComAtprotoAdminDefs,
 } from '@atproto/api'
 import { SectionHeader } from '../../components/SectionHeader'
 import { ModActionIcon } from '@/common/ModActionIcon'
@@ -23,16 +24,14 @@ import { SubjectTable } from 'components/subject/table'
 import { useTitle } from 'react-use'
 import { LanguagePicker } from '@/common/LanguagePicker'
 import { QueueSelector, QUEUE_NAMES } from '@/reports/QueueSelector'
-import { unique } from '@/lib/util'
+import { simpleHash, unique } from '@/lib/util'
 import { useEmitEvent } from '@/mod-event/helpers/emitEvent'
 import { useFluentReportSearchParams } from '@/reports/useFluentReportSearch'
 import { useLabelerAgent } from '@/shell/ConfigurationContext'
 import { WorkspacePanel } from 'components/workspace/Panel'
 import { useWorkspaceOpener } from '@/common/useWorkspaceOpener'
-import {
-  EmbedTypePicker,
-  EmbedTypePickerForModerationQueue,
-} from '@/common/EmbedTypePicker'
+import { EmbedTypePickerForModerationQueue } from '@/common/EmbedTypePicker'
+import { QUEUE_SEED } from '@/lib/constants'
 
 const TABS = [
   {
@@ -389,17 +388,13 @@ const getQueueItems = async (
     ...queryParams,
   })
 
-  const queueDivider = QUEUE_NAMES.length
   const queueIndex = QUEUE_NAMES.indexOf(queueName ?? '')
   const statusesInQueue = queueName
     ? data.subjectStatuses.filter((status) => {
-        const subjectDid =
-          status.subject.$type === 'com.atproto.admin.defs#repoRef'
-            ? status.subject.did
-            : new AtUri(`${status.subject.uri}`).host
-        const queueDeciderCharCode =
-          `${subjectDid}`.split(':').pop()?.charCodeAt(0) || 0
-        return queueDeciderCharCode % queueDivider === queueIndex
+        const subjectDid = ComAtprotoAdminDefs.isRepoRef(status.subject)
+          ? status.subject.did
+          : new AtUri(`${status.subject.uri}`).host
+        return getQueueIndex(subjectDid) === queueIndex
       })
     : data.subjectStatuses
 
@@ -420,3 +415,7 @@ const getQueueItems = async (
 
   return { cursor: data.cursor, subjectStatuses: statusesInQueue }
 }
+
+function getQueueIndex(did: string) {
+  return simpleHash(did + QUEUE_SEED) % QUEUE_NAMES.length
+}

lib/constants.ts

@@ -14,6 +14,8 @@ export const PLC_DIRECTORY_URL =
 
 export const QUEUE_CONFIG = process.env.NEXT_PUBLIC_QUEUE_CONFIG || '{}'
 
+export const QUEUE_SEED = process.env.NEXT_PUBLIC_QUEUE_SEED || ''
+
 export const SOCIAL_APP_URL =
   process.env.NEXT_PUBLIC_SOCIAL_APP_URL ||
   (process.env.NODE_ENV === 'development'

lib/util.ts

@@ -171,3 +171,13 @@ export function chunkArray<T>(arr: T[], chunkSize: number) {
   }
   return chunks
 }
+
+// @NOTE hash function is insecure, though suitable for basic purposes such as bucketing.
+export function simpleHash(str: string) {
+  let hash = 0
+  for (let i = 0; i < str.length; ++i) {
+    const chr = str.charCodeAt(i)
+    hash = ((hash << 5) - hash + chr) | 0
+  }
+  return hash
+}