feat: add method for mode discovery

Signed-off-by: Muhammad Aaqil <[email protected]>

lib/datasource.js

@@ -499,7 +499,15 @@ DataSource.prototype.setup = function(dsName, settings) {
           debug('Connection fails: %s\nIt will be retried for the next request.', err);
         } else {
           g.error('Connection fails: %s\nIt will be retried for the next request.', err);
-          this.emit('error', err);
+          if (settings.catchFailure) {
+            try {
+              this.emit('error', err);
+            } catch (error) {
+              console.log(error);
+            }
+          } else {
+            this.emit('error', err);
+          }
         }
       } else {
         // Either lazyConnect or connector initialize() defers the connection
@@ -1162,6 +1170,24 @@ DataSource.prototype.autoupdate = function(models, cb) {
   return cb.promise;
 };
 
+/**
+ * Discover if database in strict mode.
+ * This method returns 0 or 1
+ *
+ * @param {Function} Callback function.  Optional.
+ */
+DataSource.prototype.discoverIsStrict = function(cb) {
+  this.freeze();
+  cb = cb || utils.createPromiseCallback();
+
+  if (this.connector.discoverIsStrict) {
+    this.connector.discoverIsStrict(cb);
+  } else if (cb) {
+    process.nextTick(cb);
+  }
+  return cb.promise;
+};
+
 /**
  * Discover existing database tables.
  * This method returns an array of model objects, including {type, name, onwer}
@@ -1625,6 +1651,7 @@ DataSource.prototype.discoverSchemas = function(tableName, options, cb) {
   if (followingRelations) {
     tasks.push(this.discoverForeignKeys.bind(this, tableName, options));
   }
+  tasks.push(this.discoverIsStrict.bind(this));
 
   async.parallel(tasks, function(err, results) {
     if (err) {
@@ -1633,6 +1660,10 @@ DataSource.prototype.discoverSchemas = function(tableName, options, cb) {
     }
 
     const columns = results[0];
+    let isStrict = results[2];
+    if (isStrict && isStrict[0]) {
+      isStrict = isStrict[0]['strictMode'];
+    }
     if (!columns || columns.length === 0) {
       cb(new Error(g.f('Table \'%s\' does not exist.', tableName)));
       return cb.promise;
@@ -1664,11 +1695,19 @@ DataSource.prototype.discoverSchemas = function(tableName, options, cb) {
 
     columns.forEach(function(item) {
       const propName = nameMapper('column', item.columnName);
+      const jsonSchema = {
+        nullable: item.nullable === 'Y' || item.nullable === 'YES' ||
+        item.nullable === 1 || item.nullable === true,
+      };
+      if (isStrict && item.dataLength) {
+        jsonSchema.maxLength = item.dataLength;
+      }
       schema.properties[propName] = {
         type: item.type,
         required: !item.generated && (item.nullable === 'N' || item.nullable === 'NO' ||
           item.nullable === 0 || item.nullable === false),
         length: item.dataLength,
+        jsonSchema,
         precision: item.dataPrecision,
         scale: item.dataScale,
         generated: item.generated,