agent: migration for dropping NOT NULL from IndexingRules.protocolnet…

…work

packages/indexer-agent/src/db/migrations/12-remove-not-null-constraint-from-protocol-network-column.ts

@@ -0,0 +1,84 @@
+import { Logger } from '@graphprotocol/common-ts'
+import { QueryTypes, QueryInterface } from 'sequelize'
+
+interface MigrationContext {
+  queryInterface: QueryInterface
+  logger: Logger
+}
+
+interface Context {
+  context: MigrationContext
+}
+
+const UNIQUE_INDEX_NAME = 'idx_unique_identifier_and_protocol_network'
+
+export async function up({ context }: Context): Promise<void> {
+  const { queryInterface } = context
+
+  const primaryKeyName = await getPrimaryKeyName(queryInterface)
+  await alterTable(primaryKeyName, queryInterface)
+}
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+export async function down({ context }: Context): Promise<void> {
+  /* TODO
+  - Drop partial unique index on IndexingRules (identifier)
+  - Infer the name and drop the unique constraint from (identifier, protocolNetwork)
+  - Add NOT NULL back to protocolNetwork, possibly removing rows where it's NULL
+  - Infer the name and drop primary key on id
+  - Create a primary key on (identifier, protocolNetwork)
+   */
+}
+
+async function getPrimaryKeyName(
+  queryInterface: QueryInterface,
+): Promise<string> {
+  const sql = `
+SELECT
+    conname
+FROM
+    pg_constraint
+    INNER JOIN pg_class ON pg_constraint.conrelid = pg_class.oid
+    INNER JOIN pg_namespace ON pg_namespace.oid = pg_class.relnamespace
+WHERE
+    pg_class.relname = 'IndexingRules'
+    AND pg_namespace.nspname = 'public'
+    AND pg_constraint.contype = 'p';
+`
+  const result: null | { conname?: string } =
+    await queryInterface.sequelize.query(sql, {
+      type: QueryTypes.SELECT,
+      raw: true,
+      plain: true,
+    })
+
+  if (!result || !result.conname) {
+    throw new Error(
+      `Failed to infer primary key constraint name for the 'IndexingRules' table.`,
+    )
+  }
+  return result.conname
+}
+
+async function alterTable(
+  primaryKey: string,
+  queryInterface: QueryInterface,
+): Promise<void> {
+  const alterTableSql = `
+ALTER TABLE "IndexingRules"
+    DROP CONSTRAINT "${primaryKey}",
+    ADD PRIMARY KEY (id),
+    ALTER COLUMN "protocolNetwork" DROP NOT NULL,
+    ADD UNIQUE ("identifier", "protocolNetwork");
+`
+
+  // We still need this partial index to enforce "identifier" uniqueness when
+  // "protocolNetwork" is null.
+  const createUniqueIndexSql = `
+CREATE UNIQUE INDEX ${UNIQUE_INDEX_NAME} ON "IndexingRules" ("identifier")
+WHERE
+    "protocolNetwork" IS NULL;
+`
+  await queryInterface.sequelize.query(alterTableSql)
+  await queryInterface.sequelize.query(createUniqueIndexSql)
+}