[clickhouse] make table engines a warning instead of an error (#2056)

There's engines like Distributed and other MergeTree family which could
also be used in special workloads. Until we have more understanding on
how these work and how common they are, don't block creation of mirrors.

flow/connectors/clickhouse/clickhouse.go

@@ -305,9 +305,9 @@ func (c *ClickhouseConnector) checkTablesEmptyAndEngine(ctx context.Context, tab
 		if totalRows != 0 {
 			return fmt.Errorf("table %s exists and is not empty", tableName)
 		}
-		if !slices.Contains(acceptableTableEngines, engine) {
-			return fmt.Errorf("table %s exists but is not using ReplacingMergeTree/MergeTree engine,"+
-				" and is using %s instead", tableName, engine)
+		if !slices.Contains(acceptableTableEngines, strings.TrimPrefix(engine, "Shared")) {
+			c.logger.Warn("[clickhouse] table engine not explicitly supported",
+				slog.String("table", tableName), slog.String("engine", engine))
 		}
 	}
 	if rows.Err() != nil {

flow/connectors/clickhouse/normalize.go

@@ -24,7 +24,7 @@ const (
 	versionColType = "Int64"
 )
 
-var acceptableTableEngines = []string{"ReplacingMergeTree", "MergeTree", "SharedReplacingMergeTree"}
+var acceptableTableEngines = []string{"ReplacingMergeTree", "MergeTree"}
 
 func (c *ClickhouseConnector) StartSetupNormalizedTables(_ context.Context) (interface{}, error) {
 	return nil, nil

ui/app/peers/create/[peerType]/schema.ts

@@ -274,7 +274,7 @@ export const chSchema = (hostDomains: string[]) =>
         invalid_type_error: 'User must be a string',
       })
       .min(1, 'User must be non-empty')
-      .max(64, 'User must be less than 64 characters'),
+      .max(128, 'User must be less than 128 characters'),
     password: z
       .string({
         invalid_type_error: 'Password must be a string',