Add a README.md file to the backup directory

__test__/backup.test.ts

@@ -27,6 +27,7 @@ let spyOnLogWarn = null;
 let spyOnLogError = null;
 let spyOnShowError = null;
 let spyOnSaveBackupInfo = null;
+let spyOnDataGet = null;
 
 const spyOnsSettingsValue = jest.spyOn(joplin.settings, "value");
 const spyOnGlobalValue = jest.spyOn(joplin.settings, "globalValue");
@@ -51,7 +52,10 @@ describe("Backup", function () {
     when(spyOnsSettingsValue)
       .mockImplementation(() => Promise.resolve("no mockImplementation"))
       .calledWith("fileLogLevel").mockImplementation(() => Promise.resolve("error"))
-      .calledWith("path").mockImplementation(() => Promise.resolve(testPath.backupBasePath));
+      .calledWith("path").mockImplementation(() => Promise.resolve(testPath.backupBasePath))
+      .calledWith("zipArchive").mockImplementation(() => "no")
+      .calledWith("execFinishCmd").mockImplementation(() => "")
+      .calledWith("usePassword").mockImplementation(() => false);
 
     /* prettier-ignore */
     when(spyOnGlobalValue)
@@ -60,6 +64,13 @@ describe("Backup", function () {
       .calledWith("locale").mockImplementation(() => Promise.resolve("en_US"))
       .calledWith("templateDir").mockImplementation(() => Promise.resolve(testPath.templates));
 
+    spyOnDataGet = jest
+      .spyOn(joplin.data, "get")
+      .mockImplementation(async (_path, _query) => ({
+        items: [],
+        hasMore: false,
+      }));
+
     await createTestStructure();
     backup = new Backup() as any;
     backup.backupStartTime = new Date();
@@ -93,6 +104,7 @@ describe("Backup", function () {
     spyOnShowError.mockReset();
     spyOnsSettingsValue.mockReset();
     spyOnGlobalValue.mockReset();
+    spyOnDataGet.mockReset();
     spyOnSaveBackupInfo.mockReset();
   });
 
@@ -1014,4 +1026,32 @@ describe("Backup", function () {
       expect(backup.log.warn).toHaveBeenCalledTimes(0);
     });
   });
+
+  describe("create backup readme", () => {
+    it.each([{ backupRetention: 1 }, { backupRetention: 2 }])(
+      "should create a README.md in the backup directory (case %#)",
+      async ({ backupRetention }) => {
+        when(spyOnsSettingsValue)
+          .calledWith("backupRetention")
+          .mockImplementation(async () => backupRetention)
+          .calledWith("backupInfo")
+          .mockImplementation(() => Promise.resolve("[]"));
+
+        backup.backupStartTime = null;
+        await backup.start();
+
+        // Should exist and be non-empty
+        const readmePath = path.join(
+          testPath.backupBasePath,
+          "JoplinBackup",
+          "README.md"
+        );
+        expect(await fs.pathExists(readmePath)).toBe(true);
+        expect(await fs.readFile(readmePath, "utf8")).not.toBe("");
+
+        // Prevent "open handle" errors
+        backup.stopTimer();
+      }
+    );
+  });
 });

package.json

@@ -28,7 +28,7 @@
     "husky": "^6.0.0",
     "jest": "^27.0.4",
     "jest-when": "^3.3.1",
-    "joplinplugindevtools": "^1.0.15",
+    "joplinplugindevtools": "^1.0.16",
     "lint-staged": "^11.0.0",
     "mime": "^2.5.2",
     "on-build-webpack": "^0.1.0",

src/Backup.ts

@@ -478,6 +478,7 @@ class Backup {
 
         const backupDst = await this.makeBackupSet();
 
+        await this.writeReadme(this.backupBasePath);
         await joplin.settings.setValue(
           "lastBackup",
           this.backupStartTime.getTime()
@@ -684,6 +685,16 @@ class Backup {
     }
   }
 
+  private async writeReadme(backupFolder: string) {
+    const readmePath = path.join(backupFolder, "README.md");
+    this.log.info("writeReadme to", readmePath);
+    const readmeText = i18n.__(
+      "backupReadme",
+      this.backupStartTime.toLocaleString()
+    );
+    await fs.writeFile(readmePath, readmeText, "utf8");
+  }
+
   private async backupNotebooks() {
     const notebooks = await this.selectNotebooks();
 

src/locales/en_US.json

@@ -86,6 +86,7 @@
       "description": "Execute command when backup is finished"
     }
   },
+  "backupReadme": "# Joplin Backup\n\nThis folder contains one or more backups of data from the Joplin note taking application. The most recent backup was created on %s.\n\nSee the [Simple Backup documentation](https://joplinapp.org/plugins/plugin/io.github.jackgruber.backup/#restore) for information about how to restore from this backup.",
   "command": {
     "createBackup": "Create backup"
   }