Question

我需要在我的ejabberd服务器中使用erlang cassandra客户端（https://github.com/iamaleksey/seestar）进行消息记录。但我可以单独运行seestar客户端。但是如果我将seestar文件包含到ejabberd src文件夹中，我遇到了function_clause错误。这个错误告诉没有找到gen_server的调用函数。请建议一些解决方案吗？

 The error when I debug the code is :
(ejabberd@localhost)1> seestar_session_tests:session_test_().
{foreach,#Fun<seestar_session_tests.0.112079720>,
         #Fun<seestar_session_tests.1.112079720>,
         [#Fun<seestar_session_tests.2.112079720>,
          #Fun<seestar_session_tests.3.112079720>,
          #Fun<seestar_session_tests.4.112079720>,
          #Fun<seestar_session_tests.5.112079720>]}
(ejabberd@localhost)2> seestar_session_tests:test_schema_queries(0.112079720).

** exception exit: {{function_clause,[{gen,call,
                                           [0.11207972,'$gen_call',
                                            {request,7,
                                                     <<0,0,0,95,67,82,69,65,84,69,32,75,69,89,83,80,...>>,
                                                     true},
                                            infinity],
                                           [{file,"gen.erl"},{line,146}]},
                                      {gen_server,call,3,[{file,"gen_server.erl"},{line,184}]},
                                      {seestar_session,request,3,
                                                       [{file,"seestar_session.erl"},{line,209}]},
                                      {seestar_session,perform,3,
                                                       [{file,"seestar_session.erl"},{line,156}]},
                                      {seestar_session_tests,test_schema_queries,1,
                                                             [{file,"seestar_session_tests.erl"},{line,33}]},
                                      {erl_eval,do_apply,6,[{file,"erl_eval.erl"},{line,576}]},
                                      {shell,exprs,7,[{file,"shell.erl"},{line,668}]},
                                      {shell,eval_exprs,7,[{file,"shell.erl"},{line,623}]}]},
                    {gen_server,call,
                                [0.11207972,
                                 {request,7,
                                          <<0,0,0,95,67,82,69,65,84,69,32,75,69,89,83,80,65,67,69,
                                            ...>>,
                                          true},
                                 infinity]}}
     in function  gen_server:call/3 (gen_server.erl, line 188)
     in call from seestar_session:request/3 (seestar_session.erl, line 209)
     in call from seestar_session:perform/3 (seestar_session.erl, line 156)
     in call from seestar_session_tests:test_schema_queries/1 (seestar_session_tests.erl, line 33)

Answer 1

您不应该直接调用seestar_session_tests中的函数，而是通过Eunit库调用。试试这个：

eunit:test(seestar_session_tests, [verbose]).

（上述错误的确切原因是seestar_session_tests:test_schema_queries需要一个pid，测试框架会给它一个pid，但是你用浮点数调用它。）

Eunit测试也可以通过Rebar从commond线调用。切换到seestar目录并运行rebar eunit。

Answer 2

您可以使用基于erlcass的Datastax Official Cpp driver。要集成，只需将其作为dep添加到rebar配置文件中：

{erlcass, ".*", {git, "https://github.com/silviucpp/erlcass.git", {tag, "v2.2"}}}

然后进入你的应用程序start方法初始化驱动程序或使用app.config中的以下内容：

{
    erlcass,
    [
        {
            cluster_options,
            [
                {contact_points, <<"127.0.0.1">>},
                {port, 9042},
                {number_threads_io, 4},
                {queue_size_io, 128000},
                {max_connections_host, 5},
                {pending_requests_high_watermark, 128000},
                {tcp_nodelay, true},
                {tcp_keepalive, {true, 1800}},
                {keyspace, <<"keyspace_kere">>}
            ]
        }
    ]
}.

如何将erlang cassandra客户端文件包含到ejabberd服务器中？

2 个答案: