Improve continuous export failure recovery by moving the export operation "progress marker" from USB drive to VxScan store

apps/central-scan/backend/src/store.ts

@@ -133,6 +133,10 @@ function dateTimeFromNoOffsetSqliteDate(noOffsetSqliteDate: string): DateTime {
 export class Store {
   private constructor(private readonly client: DbClient) {}
 
+  // Used by shared CVR export logic in libs/backend
+  // eslint-disable-next-line vx/gts-no-public-class-fields
+  readonly scannerType = 'central';
+
   getDbPath(): string {
     return this.client.getDatabasePath();
   }

apps/scan/backend/schema.sql

@@ -51,13 +51,19 @@ create table sheets (
 );
 
 create table system_settings (
-  -- enforce singleton table
+  -- Enforce singleton table
   id integer primary key check (id = 1),
   data text not null -- JSON blob
 );
 
+create table is_continuous_export_operation_in_progress (
+  -- Enforce singleton table
+  id integer primary key check (id = 1),
+  is_continuous_export_operation_in_progress boolean not null
+);
+
 create table export_directory_name (
-  -- enforce singleton table
+  -- Enforce singleton table
   id integer primary key check (id = 1),
   export_directory_name text not null
 );

apps/scan/backend/src/store.ts

@@ -129,6 +129,10 @@ export class Store {
     private readonly uiStringsStore: UiStringsStore
   ) {}
 
+  // Used by shared CVR export logic in libs/backend
+  // eslint-disable-next-line vx/gts-no-public-class-fields
+  readonly scannerType = 'precinct';
+
   getDbPath(): string {
     return this.client.getDatabasePath();
   }
@@ -823,15 +827,44 @@ export class Store {
     return safeParseSystemSettings(result.data).unsafeUnwrap();
   }
 
+  isContinuousExportOperationInProgress(): boolean {
+    const row = this.client.one(
+      `
+      select
+        is_continuous_export_operation_in_progress as isContinuousExportOperationInProgress
+      from is_continuous_export_operation_in_progress
+      `
+    ) as { isContinuousExportOperationInProgress: number } | undefined;
+    return Boolean(row?.isContinuousExportOperationInProgress);
+  }
+
+  setIsContinuousExportOperationInProgress(
+    isContinuousExportOperationInProgress: boolean
+  ): void {
+    this.client.run('delete from is_continuous_export_operation_in_progress');
+    this.client.run(
+      `
+      insert into is_continuous_export_operation_in_progress (
+        is_continuous_export_operation_in_progress
+      ) values (?)
+      `,
+      isContinuousExportOperationInProgress ? 1 : 0
+    );
+  }
+
   /**
    * Gets the name of the directory that we're continuously exporting to, e.g.
    * TEST__machine_SCAN-0001__2023-08-16_17-02-24. Returns undefined if not yet set.
    */
   getExportDirectoryName(): string | undefined {
-    const result = this.client.one(
-      'select export_directory_name as exportDirectoryName from export_directory_name'
+    const row = this.client.one(
+      `
+      select
+        export_directory_name as exportDirectoryName
+      from export_directory_name
+      `
     ) as { exportDirectoryName: string } | undefined;
-    return result?.exportDirectoryName;
+    return row?.exportDirectoryName;
   }
 
   /**
@@ -840,7 +873,11 @@ export class Store {
   setExportDirectoryName(exportDirectoryName: string): void {
     this.client.run('delete from export_directory_name');
     this.client.run(
-      'insert into export_directory_name (export_directory_name) values (?)',
+      `
+      insert into export_directory_name (
+        export_directory_name
+      ) values (?)
+      `,
       exportDirectoryName
     );
   }