Add support for NATS credentials file

docs/en/engines/table-engines/integrations/nats.md

@@ -38,6 +38,7 @@ CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
     [nats_username = 'user',]
     [nats_password = 'password',]
     [nats_token = 'clickhouse',]
+    [nats_credential_file = '/var/nats_credentials',]
     [nats_startup_connect_tries = '5']
     [nats_max_rows_per_message = 1,]
     [nats_handle_error_mode = 'default']
@@ -63,6 +64,7 @@ Optional parameters:
 - `nats_username` - NATS username.
 - `nats_password` - NATS password.
 - `nats_token` - NATS auth token.
+- `nats_credential_file` - Path to a NATS credentials file.
 - `nats_startup_connect_tries` - Number of connect tries at startup. Default: `5`.
 - `nats_max_rows_per_message` — The maximum number of rows written in one NATS message for row-based formats. (default : `1`).
 - `nats_handle_error_mode` — How to handle errors for RabbitMQ engine. Possible values: default (the exception will be thrown if we fail to parse a message), stream (the exception message and raw message will be saved in virtual columns `_error` and `_raw_message`).

src/Storages/NATS/NATSConnection.cpp

@@ -91,6 +91,8 @@ void NATSConnectionManager::connectImpl()
         natsOptions_SetUserInfo(options, configuration.username.c_str(), configuration.password.c_str());
     if (!configuration.token.empty())
         natsOptions_SetToken(options, configuration.token.c_str());
+    if (!configuration.credential_file.empty())
+        natsOptions_SetUserCredentialsFromFiles(options, configuration.credential_file.c_str(), nullptr);
 
     if (configuration.secure)
     {

src/Storages/NATS/NATSConnection.h

@@ -14,6 +14,7 @@ struct NATSConfiguration
     String username;
     String password;
     String token;
+    String credential_file;
 
     int max_reconnect;
     int reconnect_wait;

src/Storages/NATS/NATSSettings.h

@@ -25,6 +25,7 @@ class ASTStorage;
     M(String, nats_username, "", "NATS username", 0) \
     M(String, nats_password, "", "NATS password", 0) \
     M(String, nats_token, "", "NATS token", 0) \
+    M(String, nats_credential_file, "", "Path to a NATS credentials file", 0) \
     M(UInt64, nats_startup_connect_tries, 5, "Number of connect tries at startup", 0) \
     M(UInt64, nats_max_rows_per_message, 1, "The maximum number of rows produced in one message for row-based formats.", 0) \
     M(StreamingHandleErrorMode, nats_handle_error_mode, StreamingHandleErrorMode::DEFAULT, "How to handle errors for NATS engine. Possible values: default (throw an exception after nats_skip_broken_messages broken messages), stream (save broken messages and errors in virtual columns _raw_message, _error).", 0) \

src/Storages/NATS/StorageNATS.cpp

@@ -67,6 +67,7 @@ StorageNATS::StorageNATS(
     auto nats_username = getContext()->getMacros()->expand(nats_settings->nats_username);
     auto nats_password = getContext()->getMacros()->expand(nats_settings->nats_password);
     auto nats_token = getContext()->getMacros()->expand(nats_settings->nats_token);
+    auto nats_credential_file = getContext()->getMacros()->expand(nats_settings->nats_credential_file);
 
     configuration =
     {
@@ -75,6 +76,7 @@ StorageNATS::StorageNATS(
         .username = nats_username.empty() ? getContext()->getConfigRef().getString("nats.user", "") : nats_username,
         .password = nats_password.empty() ? getContext()->getConfigRef().getString("nats.password", "") : nats_password,
         .token = nats_token.empty() ? getContext()->getConfigRef().getString("nats.token", "") : nats_token,
+        .credential_file = nats_credential_file.empty() ? getContext()->getConfigRef().getString("nats.credential_file", "") : nats_credential_file,
         .max_reconnect = static_cast<int>(nats_settings->nats_max_reconnect.value),
         .reconnect_wait = static_cast<int>(nats_settings->nats_reconnect_wait.value),
         .secure = nats_settings->nats_secure.value