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Notes about the project rationals

Just some notes for future me about the project decisions was made.

Keywords naming and namespace rationale

How to name parameters namespace? a1) ppconsul::keywords::service_id !! too detailed

  • a2) ppconsul::keywords::id !!! b1) ppconsul::_service_id ! not clear that it's about keywords b2) ppconsul::_id !

Registration interface rationale 2

  1. Registration object + extra keywords vs flat set of keywords

agent.registerCheck( keywords::name = "", keywords::check*** = agent::ScriptCheck{"ccc.sh", std::chrono::seconds(20)}, keywords::notes = "", keywords::id = "", keywords::token = "" );

agent.registerCheck( { keywords::name = "", keywords::check*** = agent::ScriptCheck{"ccc.sh", std::chrono::seconds(20)}, keywords::notes = "", keywords::id = "" }, keywords::token = "" );

  1. Use keyword arguments for all field (a) s vs only for optional ones (b)

a) agent.registerCheck( { keywords::name = "", keywords::check*** = agent::ScriptCheck{"ccc.sh", std::chrono::seconds(20)}, keywords::notes = "", keywords::id = "" }, keywords::token = "" ); or even agent.registerCheck( { keywords::name = "", keywords::script_check = {"ccc.sh", std::chrono::seconds(20)}, keywords::notes = "", keywords::id = "" }, keywords::token = "" );

b) agent.registerCheck( { "name", agent::ScriptCheck{"ccc.sh", std::chrono::seconds(20)}, keywords::notes = "", keywords::id = "" }, keywords::token = "" );

Registration interface rationale

Checks: All checks has "name", "id" = name, "notes" = "", "name" = "service:" for a service checks.

  • TTL: "ttl"
  • Script: "script" + "interval" [+ "timeout"]
  • HTTP: "http" + "interval" [+ "timeout"]
  • Docker: "docker_container_id" + "shell" + "script" + "interval"
// New style 1: all optional params are keywords
agent.registerCheck("check1", params::ttl=std::chrono::seconds(10));
agent.registerCheck("check1", params::notes="", params::ttl=std::chrono::seconds(10));
agent.registerCheck("check1", params::notes="", params::script="bla-bla.py", params::interval=std::chrono::seconds(10));
agent.registerService("service1", params::tags={"udp", "service1", "service2"}, params::ttl=std::chrono::seconds(10));
agent.registerService("service1", params::tags={"udp", "service1", "service2"}, params::script="bla-bla.py", params::interval=std::chrono::seconds(10));

// New style 2: structures with keywords
agent.registerCheck({"check1", params::notes="bla-bla"}, HttpCheck("http://localhost/test", std::chrono::seconds(10), params::tiemout=std::chrono::seconds(2)));
agent.registerService({"service1", params::tags={"udp", "service1", "service2"}});
// ...

// New Style 3: higher granulated keywords
agent.registerCheck("check1", params::notes="", params::ttl_check={std::chrono::seconds(10)});
agent.registerCheck("check1", params::notes="", params::script_check={params::script="bla-bla.py", params::interval=std::chrono::seconds(10)});
agent.registerService("service1", params::tags={"udp", "service1", "service2"});
agent.registerService("service1", params::tags={"udp", "service1", "service2"}, params::ttl_check={std::chrono::seconds(10)});
agent.registerService("service1", params::tags={"udp", "service1", "service2"}, params::script_check={"bla-bla.py", std::chrono::seconds(10), params::timeout=std::chrono::seconds(2)});

// New Style 4: higher granulated keywords using variant
agent.registerCheck("check1", TtlCheck{std::chrono::seconds(10)});
agent.registerCheck("check1", ScriptCheck{"bla-bla.py", std::chrono::seconds(10), params::timeout=std::chrono::seconds(2)}, params::notes="");
agent.registerService("service1", params::tags={"udp", "service1", "service2"});
agent.registerService("service1", params::tags={"udp", "service1", "service2"}, params::check=TtlCheck{std::chrono::seconds(10)});
agent.registerService("service1", params::tags={"udp", "service1", "service2"}, params::check=ScriptCheck{"bla-bla.py", std::chrono::seconds(10), params::timeout=std::chrono::seconds(2)});

Option 4 seems the most descriptive, clear and intuitive.

        Qs:
        1) Where to put data types - under the root namespace or under the endpoint's namespace?
            - some types are shared between endpoints, some types are different (with the same name) in different endpoints
            - probably better unique names should be found, so all types can be placed to the root namespace?
        2) Why are endpoint namespaces needed at all?
            - To avoid conflicts between entities related to different endpoints

        3) Typed parameters for check params, yes or no?

            ppconsul::agent::params::check_params = ppconsul::agent::TtlCheckParams{std::chrono::minutes(5)}
            ppconsul::agent::params::check_params = ppconsul::agent::ScriptCheckParams{"run.sh", std::chrono::minutes(5)}
     
            vs

            ppconsul::agent::params::ttl_check = {std::chrono::minutes(5)}
            ppconsul::agent::params::scipt_check = {"run.sh", std::chrono::minutes(5), "bla-bla"}
     

        5) Has user to provide a RegistrationData object?
             a) agent.registerService()



        Ex:
        1) current approach
            ppconsul::agent::Agent agent(consul);

            agent.registerService({
                name,
                ppconsul::kw::check = ppconsul::agent::TtlCheckParams{std::chrono::minutes(5)},
                ppconsul::kw::params::id = "id"
            });
         
            Long, collision between structures related to a one endpoint is possible

        2) remove endpoint namespace
            ppconsul::Agent agent(consul);

            agent.registerService({
                name,
                ppconsul::params::check = ppconsul::agent::TtlCheckParams{std::chrono::minutes(5)},
                ppconsul::params::id = "id"
            });
     
            Still noisy, collisions between endpoints
     
        3) instead of endpoint's, use a type's namespace
             ppconsul::agent::Agent agent(consul);

             agent.registerService({
                name,
                ppconsul::service::check = ppconsul::agent::TtlCheckParams{std::chrono::minutes(5)},
                ppconsul::service::id = "id"
             });
     
             Name is not obvious at all. There is confusion between different approach to name endpoints

         4)
             ppconsul::agent::Agent agent(consul);

             agent.registerService({
                name,
                ppconsul::agent::service_check = ppconsul::agent::TtlCheckParams{std::chrono::minutes(5)},
                ppconsul::agent::service_id = "id"
             });