Add tool to merge yaml configs

ydb/tools/merge_yaml/main.cpp

@@ -0,0 +1,53 @@
+#include <ydb/library/yaml_config/yaml_config.h>
+#include <ydb/library/yaml_config/yaml_config_parser.h>
+#include <ydb/library/fyamlcpp/fyamlcpp.h>
+
+#include <fstream>
+
+using namespace NKikimr;
+
+int main(int argc, char **argv) {
+    if (argc != 4) {
+        Cerr << "usage: " << argv[0] << " <input_yaml> <tenant> <output_yaml>" << Endl;
+        return 1;
+    }
+
+    auto inputFile = argv[1];
+    auto tenant = argv[2];
+    auto outputFile = argv[3];
+
+    std::ifstream inputStream(inputFile);
+    std::ofstream outputStream(outputFile);
+
+    if (!inputStream.is_open() || !outputStream.is_open()) {
+        Cerr << "Can't open file " << (inputStream.is_open() ? outputFile : inputFile) << Endl;
+        return 1;
+    }
+
+    std::stringstream inputBuf;
+    TStringStream outputBuf;
+
+    inputBuf << inputStream.rdbuf();
+    inputStream.close();
+
+    auto doc = NFyaml::TDocument::Parse(inputBuf.str());
+    auto [resolved, node] = NYamlConfig::Resolve(
+        doc,
+        {
+            NYamlConfig::TNamedLabel{"tenant", tenant},
+        }
+    );
+
+    outputBuf << node;
+
+    outputStream << outputBuf.Str();
+
+    if (outputStream.flush().fail()) {
+        Cerr << "Can't write to file " << outputFile << Endl;
+        return 1;
+    }
+
+    outputStream.close();
+
+    return 0;
+}

ydb/tools/merge_yaml/ya.make

@@ -0,0 +1,12 @@
+PROGRAM()
+
+SRCS(
+    main.cpp
+)
+
+PEERDIR(
+    ydb/library/yaml_config
+    ydb/library/fyamlcpp
+)
+
+END()

ydb/tools/ya.make

@@ -1,6 +1,7 @@
 RECURSE(
     blobsan
     cfg
+    merge_yaml
     partcheck
     query_replay
     query_replay_yt