Optionally read options from environment

Dockerfile.flex

@@ -10,7 +10,7 @@ COPY . /workspace
 RUN cmake --preset flex \
  && cmake --build --preset flex
 
-RUN apt-get update && apt-get install net-tools
+RUN apt-get update && apt-get install -y --no-install-recommends net-tools
 
 FROM scratch
 

postmaster/flex/Main.cpp

@@ -11,6 +11,7 @@
 #include "services/network_instantiations/NetworkAdapter.hpp"
 #include "services/tracer/GlobalTracer.hpp"
 #include "services/tracer/TracerOnIoOutputInfrastructure.hpp"
+#include <cstdlib>
 
 int main(int argc, const char* argv[], const char* env[])
 {
@@ -24,23 +25,33 @@ int main(int argc, const char* argv[], const char* env[])
 
     try
     {
-        parser.ParseCLI(argc, argv);
+        std::string firmwareArg = std::getenv("POSTMASTER_FIRMWARE");
+        std::string urlArg = std::getenv("POSTMASTER_IP");
+        std::string passwordArg = std::getenv("POSTMASTER_PASSWORD");
+
+        if (firmwareArg.empty() && urlArg.empty())
+        {
+            parser.ParseCLI(argc, argv);
+            firmwareArg = args::get(firmwareArgument);
+            urlArg = args::get(urlArgument);
+            passwordArg = args::get(passwordArgument);
+        }
 
         static hal::TimerServiceGeneric timerService;
         static hal::SynchronousRandomDataGeneratorGeneric randomDataGenerator;
         static main_::TracerOnIoOutputInfrastructure tracer;
         static main_::NetworkAdapter network;
         static hal::FileSystemGeneric fileSystem;
 
-        static auto firmware = firmwareArgument ? fileSystem.ReadBinaryFile(args::get(firmwareArgument)) : std::vector<uint8_t>{};
+        static auto firmware = !firmwareArg.empty() ? fileSystem.ReadBinaryFile(firmwareArg) : std::vector<uint8_t>{};
 
         static services::HttpClientConnectorWithNameResolverImpl<> connector(network.ConnectionFactoryWithNameResolver());
-        static infra::BoundedString::WithStorage<512> httpUrl{ args::get(urlArgument) };
-        static infra::BoundedString::WithStorage<512> webSocketUrl{ args::get(urlArgument) };
+        static infra::BoundedString::WithStorage<512> httpUrl{ urlArg };
+        static infra::BoundedString::WithStorage<512> webSocketUrl{ urlArg };
         static application::EchoWebSocketClientFactory webSocketFactory(webSocketUrl, 80, network.ConnectionFactory(), tracer.tracer);
         static services::HttpClientWebSocketInitiation webSocketInitiation(webSocketFactory, connector,
             webSocketFactory, randomDataGenerator, services::noAutoConnect);
-        static application::HttpClientAuthenticationDigest::WithMaxHeaders<10> clientAuthentication{ args::get(passwordArgument), randomDataGenerator };
+        static application::HttpClientAuthenticationDigest::WithMaxHeaders<10> clientAuthentication{ passwordArg, randomDataGenerator };
         static services::HttpClientAuthenticationConnector clientAuthenticationConnector{ connector, clientAuthentication };
         static application::FlexHttpClient httpClient(httpUrl, 80, clientAuthenticationConnector, firmware, webSocketInitiation, tracer.tracer);