witness node accepts private key from file

libraries/plugins/witness/include/graphene/witness/witness.hpp

@@ -71,6 +71,7 @@ class witness_plugin : public graphene::app::plugin {
    void schedule_production_loop();
    block_production_condition::block_production_condition_enum block_production_loop();
    block_production_condition::block_production_condition_enum maybe_produce_block( fc::limited_mutable_variant_object& capture );
+   void add_private_key(const std::string& key_id_to_wif_pair_string);
 
    /// Fetch signing keys of all witnesses in the cache from object database and update the cache accordingly
    void refresh_witness_key_cache();

libraries/plugins/witness/witness.cpp

@@ -29,6 +29,9 @@
 #include <graphene/utilities/key_conversion.hpp>
 
 #include <fc/thread/thread.hpp>
+#include <fc/io/fstream.hpp>
+
+#include <boost/filesystem/path.hpp>
 
 #include <iostream>
 
@@ -74,6 +77,10 @@ void witness_plugin::plugin_set_program_options(
           DEFAULT_VALUE_VECTOR(std::make_pair(chain::public_key_type(default_priv_key.get_public_key()),
                 graphene::utilities::key_to_wif(default_priv_key))),
                 "Tuple of [PublicKey, WIF private key] (may specify multiple times)")
+         ("private-key-file", bpo::value<vector<boost::filesystem::path>>()->composing()->multitoken(),
+          "Path to a file containing tuples of [PublicKey, WIF private key]."
+          " The file has to contain exactly one tuple (i.e. private - public key pair) per line."
+          " This option may be specified multiple times, thus multiple files can be provided.")
          ;
    config_file_options.add(command_line_options);
 }
@@ -83,6 +90,32 @@ std::string witness_plugin::plugin_name()const
    return "witness";
 }
 
+void witness_plugin::add_private_key(const std::string& key_id_to_wif_pair_string)
+{
+   auto key_id_to_wif_pair = graphene::app::dejsonify<std::pair<chain::public_key_type, std::string>>
+         (key_id_to_wif_pair_string, 5);
+   fc::optional<fc::ecc::private_key> private_key = graphene::utilities::wif_to_key(key_id_to_wif_pair.second);
+   if (!private_key)
+   {
+      // the key isn't in WIF format; see if they are still passing the old native private key format.  This is
+      // just here to ease the transition, can be removed soon
+      try
+      {
+         private_key = fc::variant(key_id_to_wif_pair.second, 2).as<fc::ecc::private_key>(1);
+      }
+      catch (const fc::exception&)
+      {
+         FC_THROW("Invalid WIF-format private key ${key_string}", ("key_string", key_id_to_wif_pair.second));
+      }
+   }
+
+   if (_private_keys.find(key_id_to_wif_pair.first) == _private_keys.end())
+   {
+      ilog("Public Key: ${public}", ("public", key_id_to_wif_pair.first));
+      _private_keys[key_id_to_wif_pair.first] = *private_key;
+   }
+}
+
 void witness_plugin::plugin_initialize(const boost::program_options::variables_map& options)
 { try {
    ilog("witness plugin:  plugin_initialize() begin");
@@ -94,24 +127,31 @@ void witness_plugin::plugin_initialize(const boost::program_options::variables_m
       const std::vector<std::string> key_id_to_wif_pair_strings = options["private-key"].as<std::vector<std::string>>();
       for (const std::string& key_id_to_wif_pair_string : key_id_to_wif_pair_strings)
       {
-         auto key_id_to_wif_pair = graphene::app::dejsonify<std::pair<chain::public_key_type, std::string> >
-               (key_id_to_wif_pair_string, 5);
-         ilog("Public Key: ${public}", ("public", key_id_to_wif_pair.first));
-         fc::optional<fc::ecc::private_key> private_key = graphene::utilities::wif_to_key(key_id_to_wif_pair.second);
-         if (!private_key)
+         add_private_key(key_id_to_wif_pair_string);
+      }
+   }
+   if (options.count("private-key-file"))
+   {
+      const std::vector<boost::filesystem::path> key_id_to_wif_pair_files =
+            options["private-key-file"].as<std::vector<boost::filesystem::path>>();
+      for (const boost::filesystem::path& key_id_to_wif_pair_file : key_id_to_wif_pair_files)
+      {
+         if (fc::exists(key_id_to_wif_pair_file))
          {
-            // the key isn't in WIF format; see if they are still passing the old native private key format.  This is
-            // just here to ease the transition, can be removed soon
-            try
-            {
-               private_key = fc::variant(key_id_to_wif_pair.second, 2).as<fc::ecc::private_key>(1);
-            }
-            catch (const fc::exception&)
+            std::string file_content;
+            fc::read_file_contents(key_id_to_wif_pair_file, file_content);
+            std::istringstream file_content_as_stream(file_content);
+
+            std::string line; // key_id_to_wif_pair_string
+            while (std::getline(file_content_as_stream, line))
             {
-               FC_THROW("Invalid WIF-format private key ${key_string}", ("key_string", key_id_to_wif_pair.second));
+               add_private_key(line);
             }
          }
-         _private_keys[key_id_to_wif_pair.first] = *private_key;
+         else
+         {
+            FC_THROW("Failed to load private key file from ${path}", ("path", key_id_to_wif_pair_file.string()));
+         }
       }
    }
    if(options.count("required-participation"))