allow file descriptor in table function file()

src/TableFunctions/TableFunctionFile.cpp

@@ -7,10 +7,92 @@
 #include <Storages/ColumnsDescription.h>
 #include <Storages/StorageFile.h>
 #include <TableFunctions/TableFunctionFactory.h>
+#include <Interpreters/evaluateConstantExpression.h>
+#include <Formats/FormatFactory.h>
+#include <Parsers/ASTIdentifier_fwd.h>
 
 namespace DB
 {
 
+namespace ErrorCodes
+{
+    extern const int UNKNOWN_IDENTIFIER;
+    extern const int LOGICAL_ERROR;
+    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
+    extern const int BAD_ARGUMENTS;
+}
+
+void TableFunctionFile::parseArguments(const ASTPtr & ast_function, ContextPtr context)
+{
+    /// Parse args
+    ASTs & args_func = ast_function->children;
+
+    if (args_func.size() != 1)
+        throw Exception("Table function '" + getName() + "' must have arguments.", ErrorCodes::LOGICAL_ERROR);
+
+    ASTs & args = args_func.at(0)->children;
+
+    if (args.empty())
+        throw Exception("Table function '" + getName() + "' requires at least 1 argument", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+
+    if (auto opt_name = tryGetIdentifierName(args[0])) {
+        if (*opt_name == "stdin")
+            fd = STDIN_FILENO;
+        else if (*opt_name == "stdout")
+            fd = STDOUT_FILENO;
+        else if (*opt_name == "stderr")
+            fd = STDERR_FILENO;
+        else
+            throw Exception("Unknow identifier '" + *opt_name + "' in first second arguments", ErrorCodes::UNKNOWN_IDENTIFIER);
+    }
+    else if (const auto * literal = args[0]->as<ASTLiteral>()) {
+        auto type = literal->value.getType();
+        if (type == Field::Types::Int64)
+            fd = static_cast<int>(literal->value.get<Int64>());
+        else if (type == Field::Types::UInt64)
+            fd = static_cast<int>(literal->value.get<UInt64>());
+        else if (type == Field::Types::String) {
+            filename = literal->value.get<String>();
+            if (filename == "-")
+                fd = 0;
+        }
+        else
+            throw Exception("The second argument of table function '" + getName() + "' mush be path or file descriptor", ErrorCodes::BAD_ARGUMENTS);
+    }
+
+    if (args.size() > 1) {
+        args[1] = evaluateConstantExpressionOrIdentifierAsLiteral(args[1], context);
+        format = args[1]->as<ASTLiteral &>().value.safeGet<String>();
+    }
+
+    if (format == "auto") {
+        if (fd >= 0)
+            format = FormatFactory::instance().getFormatFromFileDescriptor(fd);
+        else
+            format = FormatFactory::instance().getFormatFromFileName(filename, true);
+    }
+
+    if (args.size() <= 2)
+        return;
+
+    if (args.size() != 3 && args.size() != 4)
+        throw Exception("Table function '" + getName() + "' requires 1, 2, 3 or 4 arguments: filename (or file descriptor), format (default auto), structure (default auto) and compression method (default auto)",
+            ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
+
+    args[2] = evaluateConstantExpressionOrIdentifierAsLiteral(args[2], context);
+    structure = args[2]->as<ASTLiteral &>().value.safeGet<String>();
+
+    if (structure.empty())
+        throw Exception(ErrorCodes::BAD_ARGUMENTS,
+            "Table structure is empty for table function '{}'. If you want to use automatic schema inference, use 'auto'",
+            ast_function->formatForErrorMessage());
+
+    if (args.size() == 4) {
+        args[3] = evaluateConstantExpressionOrIdentifierAsLiteral(args[3], context);
+        compression_method = args[3]->as<ASTLiteral &>().value.safeGet<String>();
+    }
+}
+
 StoragePtr TableFunctionFile::getStorage(const String & source,
     const String & format_, const ColumnsDescription & columns,
     ContextPtr global_context, const std::string & table_name,
@@ -28,6 +110,8 @@ StoragePtr TableFunctionFile::getStorage(const String & source,
         ConstraintsDescription{},
         String{},
     };
+    if (fd >= 0)
+        return StorageFile::create(fd, args);
 
     return StorageFile::create(source, global_context->getUserFilesPath(), args);
 }

src/TableFunctions/TableFunctionFile.h

@@ -21,6 +21,10 @@ public:
     }
 
     ColumnsDescription getActualTableStructure(ContextPtr context) const override;
+    void parseArguments(const ASTPtr & ast_function, ContextPtr context) override;
+
+protected:
+    int fd = -1;
 
 private:
     StoragePtr getStorage(

tests/queries/0_stateless/02286_use_file_descriptor_in_table_function_file.reference

@@ -0,0 +1,8 @@
+1	2
+3	4
+1	2
+3	4
+1	2
+3	4
+1	2
+3	4

tests/queries/0_stateless/02286_use_file_descriptor_in_table_function_file.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Tags: no-parallel
+
+CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CUR_DIR"/../shell_config.sh
+
+echo -e "1,2\n3,4" > 02286_data.csv
+
+$CLICKHOUSE_LOCAL --query "SELECT * FROM file(0, CSV)" < 02286_data.csv
+$CLICKHOUSE_LOCAL --query "SELECT * FROM file(stdin, CSV)" < 02286_data.csv
+$CLICKHOUSE_LOCAL --query "SELECT * FROM file('-', CSV)" < 02286_data.csv
+$CLICKHOUSE_LOCAL --query "SELECT * FROM file(5, CSV)" 5< 02286_data.csv
+
+rm 02286_data.csv