Export backup prior to migration

Closes #847
- Added logic to export database to the `core\server\data\` folder prior
to beginning a migration.
- Factored out versioning logic from migration to prevent circular
references

core/server/data/export/index.js

@@ -1,8 +1,8 @@
-var when      = require('when'),
-    _         = require('lodash'),
-    migration = require('../migration'),
-    knex      = require('../../models/base').knex,
-    schema    = require('../schema').tables,
+var _          = require('lodash'),
+    when       = require('when'),
+    versioning = require('../versioning'),
+    knex       = require('../../models/base').knex,
+    schema     = require('../schema').tables,
 
     excludedTables = ['sessions'],
     exporter;
@@ -10,7 +10,7 @@ var when      = require('when'),
 exporter = function () {
     var tablesToExport = _.keys(schema);
 
-    return when.join(migration.getDatabaseVersion(), tablesToExport).then(function (results) {
+    return when.join(versioning.getDatabaseVersion(), tablesToExport).then(function (results) {
         var version = results[0],
             tables = results[1],
             selectOps = _.map(tables, function (name) {

core/server/data/migration/index.js

@@ -1,18 +1,20 @@
 var _               = require('lodash'),
     when            = require('when'),
+    path            = require('path'),
+    fs              = require('fs'),
+    nodefn          = require('when/node/function'),
     errors          = require('../../errors'),
     client          = require('../../models/base').client,
     knex            = require('../../models/base').knex,
     sequence        = require('when/sequence'),
 
-    defaultSettings = require('../default-settings'),
+    versioning      = require('../versioning'),
     Settings        = require('../../models/settings').Settings,
     fixtures        = require('../fixtures'),
     schema          = require('../schema').tables,
+    dataExport      = require('../export'),
 
-    initialVersion  = '000',
     schemaTables    = _.keys(schema),
-    defaultDatabaseVersion,
 
     init,
     reset,
@@ -20,58 +22,6 @@ var _               = require('lodash'),
     migrateUpFreshDb,
     getTables;
 
-// Default Database Version
-// The migration version number according to the hardcoded default settings
-// This is the version the database should be at or migrated to
-function getDefaultDatabaseVersion() {
-    if (!defaultDatabaseVersion) {
-        // This be the current version according to the software
-        defaultDatabaseVersion = _.find(defaultSettings.core, function (setting) {
-            return setting.key === 'databaseVersion';
-        }).defaultValue;
-    }
-
-    return defaultDatabaseVersion;
-}
-
-// Database Current Version
-// The migration version number according to the database
-// This is what the database is currently at and may need to be updated
-function getDatabaseVersion() {
-    return knex.schema.hasTable('settings').then(function (exists) {
-        // Check for the current version from the settings table
-        if (exists) {
-            // Temporary code to deal with old databases with currentVersion settings
-            return knex('settings')
-                .where('key', 'databaseVersion')
-                .orWhere('key', 'currentVersion')
-                .select('value')
-                .then(function (versions) {
-                    var databaseVersion = _.reduce(versions, function (memo, version) {
-                        if (isNaN(version.value)) {
-                            errors.throwError('Database version is not recognised');
-                        }
-                        return parseInt(version.value, 10) > parseInt(memo, 10) ? version.value : memo;
-                    }, initialVersion);
-
-                    if (!databaseVersion || databaseVersion.length === 0) {
-                        // we didn't get a response we understood, assume initialVersion
-                        databaseVersion = initialVersion;
-                    }
-
-                    return databaseVersion;
-                });
-        }
-        throw new Error('Settings table does not exist');
-    });
-}
-
-function setDatabaseVersion() {
-    return knex('settings')
-        .where('key', 'databaseVersion')
-        .update({ 'value': defaultDatabaseVersion });
-}
-
 function createTable(table) {
     return knex.schema.createTable(table, function (t) {
         var column,
@@ -168,8 +118,8 @@ init = function () {
     // 2. The database exists but is out of date
     // 3. The database exists but the currentVersion setting does not or cannot be understood
     // 4. The database has not yet been created
-    return getDatabaseVersion().then(function (databaseVersion) {
-        var defaultVersion = getDefaultDatabaseVersion();
+    return versioning.getDatabaseVersion().then(function (databaseVersion) {
+        var defaultVersion = versioning.getDefaultDatabaseVersion();
         if (databaseVersion === defaultVersion) {
             // 1. The database exists and is up-to-date
             return when.resolve();
@@ -179,7 +129,7 @@ init = function () {
             // Migrate to latest version
             return self.migrateUp().then(function () {
                 // Finally update the databases current version
-                return setDatabaseVersion();
+                return versioning.setDatabaseVersion();
             });
         }
         if (databaseVersion > defaultVersion) {
@@ -249,9 +199,20 @@ function checkMySQLPostTable() {
     });
 }
 
+function backupDatabase() {
+    return dataExport().then(function (exportedData) {
+        // Save the exported data to the file system for download
+        var fileName = path.resolve(__dirname + '/../exported-' + (new Date().getTime()) + '.json');
+
+        return nodefn.call(fs.writeFile, fileName, JSON.stringify(exportedData));
+    });
+}
+
 // Migrate from a specific version to the latest
 migrateUp = function () {
-    return getTables().then(function (oldTables) {
+    return backupDatabase().then(function () {
+        return getTables();
+    }).then(function (oldTables) {
         // if tables exist and client is mysqls check if posts table is okay
         if (!_.isEmpty(oldTables) && client === 'mysql') {
             return checkMySQLPostTable().then(function () {
@@ -293,7 +254,6 @@ getTables = function () {
 };
 
 module.exports = {
-    getDatabaseVersion: getDatabaseVersion,
     init: init,
     reset: reset,
     migrateUp: migrateUp,

core/server/data/versioning/index.js

@@ -0,0 +1,66 @@
+var _               = require('lodash'),
+    errors          = require('../../errors'),
+    knex            = require('../../models/base').knex,
+
+    defaultSettings = require('../default-settings'),
+
+    initialVersion  = '000',
+    defaultDatabaseVersion;
+
+// Default Database Version
+// The migration version number according to the hardcoded default settings
+// This is the version the database should be at or migrated to
+function getDefaultDatabaseVersion() {
+    if (!defaultDatabaseVersion) {
+        // This be the current version according to the software
+        defaultDatabaseVersion = _.find(defaultSettings.core, function (setting) {
+            return setting.key === 'databaseVersion';
+        }).defaultValue;
+    }
+
+    return defaultDatabaseVersion;
+}
+
+// Database Current Version
+// The migration version number according to the database
+// This is what the database is currently at and may need to be updated
+function getDatabaseVersion() {
+    return knex.schema.hasTable('settings').then(function (exists) {
+        // Check for the current version from the settings table
+        if (exists) {
+            // Temporary code to deal with old databases with currentVersion settings
+            return knex('settings')
+                .where('key', 'databaseVersion')
+                .orWhere('key', 'currentVersion')
+                .select('value')
+                .then(function (versions) {
+                    var databaseVersion = _.reduce(versions, function (memo, version) {
+                        if (isNaN(version.value)) {
+                            errors.throwError('Database version is not recognised');
+                        }
+                        return parseInt(version.value, 10) > parseInt(memo, 10) ? version.value : memo;
+                    }, initialVersion);
+
+                    if (!databaseVersion || databaseVersion.length === 0) {
+                        // we didn't get a response we understood, assume initialVersion
+                        databaseVersion = initialVersion;
+                    }
+
+                    return databaseVersion;
+                });
+        }
+        throw new Error('Settings table does not exist');
+    });
+}
+
+function setDatabaseVersion() {
+    return knex('settings')
+        .where('key', 'databaseVersion')
+        .update({ 'value': defaultDatabaseVersion });
+}
+
+module.exports = {
+    getDefaultDatabaseVersion: getDefaultDatabaseVersion,
+    getDatabaseVersion: getDatabaseVersion,
+    setDatabaseVersion: setDatabaseVersion
+};

core/test/unit/export_spec.js

@@ -8,6 +8,7 @@ var testUtils = require('../utils'),
 
     // Stuff we are testing
     migration = require('../../server/data/migration'),
+    versioning = require('../../server/data/versioning'),
     exporter = require('../../server/data/export'),
     Settings = require('../../server/models/settings').Settings;
 
@@ -39,7 +40,7 @@ describe("Exporter", function () {
 
     it("exports data", function (done) {
         // Stub migrations to return 000 as the current database version
-        var migrationStub = sandbox.stub(migration, "getDatabaseVersion", function () {
+        var versioningStub = sandbox.stub(versioning, "getDatabaseVersion", function () {
             return when.resolve("003");
         });
 
@@ -61,7 +62,7 @@ describe("Exporter", function () {
             // should not export sqlite data
             should.not.exist(exportData.data.sqlite_sequence);
 
-            migrationStub.restore();
+            versioningStub.restore();
             done();
         }).catch(done);
     });

core/test/unit/import_spec.js

@@ -8,8 +8,9 @@ var testUtils = require('../utils'),
     errors    = require('../../server/errors'),
 
     // Stuff we are testing
-    knex        = require("../../server/models/base").knex,
+    knex        = require('../../server/models/base').knex,
     migration   = require('../../server/data/migration'),
+    versioning  = require('../../server/data/versioning'),
     exporter    = require('../../server/data/export'),
     importer    = require('../../server/data/import'),
     Importer000 = require('../../server/data/import/000'),
@@ -113,7 +114,7 @@ describe("Import", function () {
 
         it("imports data from 000", function (done) {
             var exportData,
-                migrationStub = sandbox.stub(migration, "getDatabaseVersion", function () {
+                versioningStub = sandbox.stub(versioning, "getDatabaseVersion", function () {
                     return when.resolve("000");
                 });
 
@@ -151,7 +152,7 @@ describe("Import", function () {
                 // test tags
                 tags.length.should.equal(exportData.data.tags.length, 'no new tags');
 
-                migrationStub.restore();
+                versioningStub.restore();
 
                 done();
             }).catch(done);