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flm01/web/api/flukso/deps/mysql/src/mysql.erl

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api: initial import of mysql driver in webmachine
2010-03-13 13:00:51 +00:00
%%%-------------------------------------------------------------------
%%% File : mysql.erl
%%% Author : Magnus Ahltorp <ahltorp@nada.kth.se>
%%% Descrip.: MySQL client.
%%%
%%% Created : 4 Aug 2005 by Magnus Ahltorp <ahltorp@nada.kth.se>
%%%
%%% Copyright (c) 2001-2004 Kungliga Tekniska H<>gskolan
%%% See the file COPYING
%%%
%%% Usage:
%%%
%%%
%%% Call one of the start-functions before any call to fetch/2
%%%
%%% start_link(Id, Host, User, Password, Database)
%%% start_link(Id, Host, Port, User, Password, Database)
%%% start_link(Id, Host, User, Password, Database, LogFun)
%%% start_link(Id, Host, Port, User, Password, Database, LogFun)
%%%
%%% Id is a connection group identifier. If you want to have more
%%% than one connection to a server (or a set of MySQL replicas),
%%% add more with
%%%
%%% connect(Id, Host, Port, User, Password, Database, Reconnect)
%%%
%%% use 'undefined' as Port to get default MySQL port number (3306).
%%% MySQL querys will be sent in a per-Id round-robin fashion.
%%% Set Reconnect to 'true' if you want the dispatcher to try and
%%% open a new connection, should this one die.
%%%
%%% When you have a mysql_dispatcher running, this is how you make a
%%% query :
%%%
%%% fetch(Id, "select * from hello") -> Result
%%% Result = {data, MySQLRes} | {updated, MySQLRes} |
%%% {error, MySQLRes}
%%%
%%% Actual data can be extracted from MySQLRes by calling the following API
%%% functions:
%%% - on data received:
%%% FieldInfo = mysql:get_result_field_info(MysqlRes)
%%% AllRows = mysql:get_result_rows(MysqlRes)
%%% with FieldInfo = list() of {Table, Field, Length, Name}
%%% and AllRows = list() of list() representing records
%%% - on update:
%%% Affected = mysql:get_result_affected_rows(MysqlRes)
%%% with Affected = integer()
%%% - on error:
%%% Reason = mysql:get_result_reason(MysqlRes)
%%% with Reason = string()
%%%
%%% If you just want a single MySQL connection, or want to manage your
%%% connections yourself, you can use the mysql_conn module as a
%%% stand-alone single MySQL connection. See the comment at the top of
%%% mysql_conn.erl.
%%%
%%%-------------------------------------------------------------------
-module(mysql).
-behaviour(gen_server).
%%--------------------------------------------------------------------
%% External exports
%%--------------------------------------------------------------------
-export([start_link/5,
start_link/6,
start_link/7,
fetch/2,
fetch/3,
get_result_field_info/1,
get_result_rows/1,
get_result_affected_rows/1,
get_result_reason/1,
quote/1,
asciz_binary/2,
connect/7
]).
%%--------------------------------------------------------------------
%% Internal exports - just for mysql_* modules
%%--------------------------------------------------------------------
-export([log/3,
log/4
]).
%%--------------------------------------------------------------------
%% Internal exports - gen_server callbacks
%%--------------------------------------------------------------------
-export([init/1,
handle_call/3,
handle_cast/2,
handle_info/2,
terminate/2,
code_change/3
]).
%%--------------------------------------------------------------------
%% Records
%%--------------------------------------------------------------------
-include("mysql.hrl").
-record(state, {
conn_list, %% list() of mysql_connection record()
log_fun %% undefined | function for logging,
}).
-record(mysql_connection, {
id, %% term(), user of 'mysql' modules id of this socket group
conn_pid, %% pid(), mysql_conn process
reconnect, %% true | false, should mysql_dispatcher try to reconnect if this connection dies?
host, %% undefined | string()
port, %% undefined | integer()
user, %% undefined | string()
password, %% undefined | string()
database %% undefined | string()
}).
%%--------------------------------------------------------------------
%% Macros
%%--------------------------------------------------------------------
-define(SERVER, mysql_dispatcher).
-define(CONNECT_TIMEOUT, 5000).
-define(LOCAL_FILES, 128).
-define(PORT, 3306).
%%====================================================================
%% External functions
%%====================================================================
%%--------------------------------------------------------------------
%% Function: start_link(Id, Host, User, Password, Database)
%% start_link(Id, Host, Port, User, Password, Database)
%% start_link(Id, Host, User, Password, Database, LogFun)
%% start_link(Id, Host, Port, User, Password, Database,
%% LogFun)
%% Id = term(), first connection-group Id
%% Host = string()
%% Port = integer()
%% User = string()
%% Password = string()
%% Database = string()
%% LogFun = undefined | function() of arity 3
%% Descrip.: Starts the MySQL client gen_server process.
%% Returns : {ok, Pid} | ignore | {error, Error}
%%--------------------------------------------------------------------
start_link(Id, Host, User, Password, Database) when is_list(Host), is_list(User), is_list(Password),
is_list(Database) ->
start_link(Id, Host, ?PORT, User, Password, Database, undefined).
start_link(Id, Host, Port, User, Password, Database) when is_list(Host), is_integer(Port), is_list(User),
is_list(Password), is_list(Database) ->
start_link(Id, Host, Port, User, Password, Database, undefined);
start_link(Id, Host, User, Password, Database, LogFun) when is_list(Host), is_list(User), is_list(Password),
is_list(Database) ->
start_link(Id, Host, ?PORT, User, Password, Database, LogFun).
start_link(Id, Host, Port, User, Password, Database, LogFun) when is_list(Host), is_integer(Port), is_list(User),
is_list(Password), is_list(Database) ->
crypto:start(),
gen_server:start_link({local, ?SERVER}, ?MODULE, [Id, Host, Port, User, Password, Database, LogFun], []).
%%--------------------------------------------------------------------
%% Function: fetch(Id, Query)
%% fetch(Id, Query, Timeout)
%% Id = term(), connection-group Id
%% Query = string(), MySQL query in verbatim
%% Timeout = integer() | infinity, gen_server timeout value
%% Descrip.: Send a query and wait for the result.
%% Returns : {data, MySQLRes} |
%% {updated, MySQLRes} |
%% {error, MySQLRes}
%% MySQLRes = term()
%%--------------------------------------------------------------------
fetch(Id, Query) when is_list(Query) ->
gen_server:call(?SERVER, {fetch, Id, Query}).
fetch(Id, Query, Timeout) when is_list(Query) ->
gen_server:call(?SERVER, {fetch, Id, Query}, Timeout).
%%--------------------------------------------------------------------
%% Function: get_result_field_info(MySQLRes)
%% MySQLRes = term(), result of fetch function on "data"
%% Descrip.: Extract the FieldInfo from MySQL Result on data received
%% Returns : FieldInfo
%% FieldInfo = list() of {Table, Field, Length, Name}
%%--------------------------------------------------------------------
get_result_field_info(#mysql_result{fieldinfo = FieldInfo}) ->
FieldInfo.
%%--------------------------------------------------------------------
%% Function: get_result_rows(MySQLRes)
%% MySQLRes = term(), result of fetch function on "data"
%% Descrip.: Extract the Rows from MySQL Result on data received
%% Returns : Rows
%% Rows = list() of list() representing records
%%--------------------------------------------------------------------
get_result_rows(#mysql_result{rows=AllRows}) ->
AllRows.
%%--------------------------------------------------------------------
%% Function: get_result_affected_rows(MySQLRes)
%% MySQLRes = term(), result of fetch function on "updated"
%% Descrip.: Extract the Rows from MySQL Result on update
%% Returns : AffectedRows
%% AffectedRows = integer()
%%--------------------------------------------------------------------
get_result_affected_rows(#mysql_result{affectedrows=AffectedRows}) ->
AffectedRows.
%%--------------------------------------------------------------------
%% Function: get_result_reason(MySQLRes)
%% MySQLRes = term(), result of fetch function on "error"
%% Descrip.: Extract the error Reason from MySQL Result on error
%% Returns : Reason
%% Reason = string()
%%--------------------------------------------------------------------
get_result_reason(#mysql_result{error=Reason}) ->
Reason.
%%--------------------------------------------------------------------
%% Function: quote(String)
%% String = string()
%% Descrip.: Quote a string so that it can be included safely in a
%% MySQL query.
%% Returns : Quoted = string()
%%--------------------------------------------------------------------
quote(String) when is_list(String) ->
[34 | lists:reverse([34 | quote(String, [])])]. %% 34 is $"
quote([], Acc) ->
Acc;
quote([0 | Rest], Acc) ->
quote(Rest, [$0, $\\ | Acc]);
quote([10 | Rest], Acc) ->
quote(Rest, [$n, $\\ | Acc]);
quote([13 | Rest], Acc) ->
quote(Rest, [$r, $\\ | Acc]);
quote([$\\ | Rest], Acc) ->
quote(Rest, [$\\ , $\\ | Acc]);
quote([39 | Rest], Acc) -> %% 39 is $'
quote(Rest, [39, $\\ | Acc]); %% 39 is $'
quote([34 | Rest], Acc) -> %% 34 is $"
quote(Rest, [34, $\\ | Acc]); %% 34 is $"
quote([26 | Rest], Acc) ->
quote(Rest, [$Z, $\\ | Acc]);
quote([C | Rest], Acc) ->
quote(Rest, [C | Acc]).
%%--------------------------------------------------------------------
%% Function: asciz_binary(Data, Acc)
%% Data = binary()
%% Acc = list(), input accumulator
%% Descrip.: Find the first zero-byte in Data and add everything
%% before it to Acc, as a string.
%% Returns : {NewList, Rest}
%% NewList = list(), Acc plus what we extracted from Data
%% Rest = binary(), whatever was left of Data, not
%% including the zero-byte
%%--------------------------------------------------------------------
asciz_binary(<<>>, Acc) ->
{lists:reverse(Acc), <<>>};
asciz_binary(<<0:8, Rest/binary>>, Acc) ->
{lists:reverse(Acc), Rest};
asciz_binary(<<C:8, Rest/binary>>, Acc) ->
asciz_binary(Rest, [C | Acc]).
%%--------------------------------------------------------------------
%% Function: connect(Id, Host, Port, User, Password, Database,
%% Reconnect)
%% Id = term(), connection-group Id
%% Host = string()
%% Port = undefined | integer()
%% User = string()
%% Password = string()
%% Database = string()
%% Reconnect = true | false
%% Descrip.: Starts a MySQL connection and, if successfull, registers
%% it with the mysql_dispatcher.
%% Returns : {ok, ConnPid} | {error, Reason}
%%--------------------------------------------------------------------
connect(Id, Host, undefined, User, Password, Database, Reconnect) ->
connect(Id, Host, ?PORT, User, Password, Database, Reconnect);
connect(Id, Host, Port, User, Password, Database, Reconnect) ->
{ok, LogFun} = gen_server:call(?SERVER, get_logfun),
case mysql_conn:start(Host, Port, User, Password, Database, LogFun) of
{ok, ConnPid} ->
MysqlConn =
case Reconnect of
true ->
#mysql_connection{id = Id,
conn_pid = ConnPid,
reconnect = true,
host = Host,
port = Port,
user = User,
password = Password,
database = Database
};
false ->
#mysql_connection{id = Id,
conn_pid = ConnPid,
reconnect = false
}
end,
case gen_server:call(?SERVER, {add_mysql_connection, MysqlConn}) of
ok ->
{ok, ConnPid};
Res ->
Res
end;
{error, Reason} ->
{error, Reason}
end.
%%--------------------------------------------------------------------
%% Function: log(LogFun, Level, Format)
%% log(LogFun, Level, Format, Arguments)
%% LogFun = undefined | function() with arity 3
%% Level = debug | normal | error
%% Format = string()
%% Arguments = list() of term()
%% Descrip.: Either call the function LogFun with the Level, Format
%% and Arguments as parameters or log it to the console if
%% LogFun is undefined.
%% Returns : void()
%%
%% Note : Exported only for use by the mysql_* modules.
%%
%%--------------------------------------------------------------------
log(LogFun, Level, Format) ->
log(LogFun, Level, Format, []).
log(LogFun, Level, Format, Arguments) when is_function(LogFun) ->
LogFun(Level, Format, Arguments);
log(undefined, _Level, Format, Arguments) ->
%% default is to log to console
io:format(Format, Arguments),
io:format("~n", []).
%%====================================================================
%% gen_server callbacks
%%====================================================================
%%--------------------------------------------------------------------
%% Function: init(Args) -> {ok, State} |
%% {ok, State, Timeout} |
%% ignore |
%% {stop, Reason}
%% Args = [Id, Host, Port, User, Password, Database, LogFun]
%% Id = term(), connection-group Id
%% Host = string()
%% Port = integer()
%% User = string()
%% Password = string()
%% Database = string()
%% LogFun = undefined | function() with arity 3
%% Descrip.: Initiates the gen_server (MySQL dispatcher).
%%--------------------------------------------------------------------
init([Id, Host, Port, User, Password, Database, LogFun]) ->
case mysql_conn:start(Host, Port, User, Password, Database, LogFun) of
{ok, ConnPid} ->
MysqlConn = #mysql_connection{id = Id,
conn_pid = ConnPid,
reconnect = true,
host = Host,
port = Port,
user = User,
password = Password,
database = Database
},
case add_mysql_conn(MysqlConn, []) of
{ok, ConnList} ->
{ok, #state{log_fun = LogFun,
conn_list = ConnList
}};
error ->
Msg = "mysql: Failed adding first MySQL connection handler to my list, exiting",
log(LogFun, error, Msg),
{error, Msg}
end;
{error, Reason} ->
log(LogFun, error, "mysql: Failed starting first MySQL connection handler, exiting"),
{stop, {error, Reason}}
end.
%%--------------------------------------------------------------------
%% Function: handle_call(Msg, From, State)
%% Descrip.: Handling call messages.
%% Returns : {reply, Reply, State} |
%% {reply, Reply, State, Timeout} |
%% {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, Reply, State} | (terminate/2 is called)
%% {stop, Reason, State} (terminate/2 is called)
%%--------------------------------------------------------------------
%%--------------------------------------------------------------------
%% Function: handle_call({fetch, Id, Query}, From, State)
%% Id = term(), connection-group id
%% Query = string(), MySQL query
%% Descrip.: Make a MySQL query. Use the first connection matching Id
%% in our connection-list. Don't block the mysql_dispatcher
%% by returning {noreply, ...} here and let the mysql_conn
%% do gen_server:reply(...) when it has an answer.
%% Returns : {noreply, NewState} |
%% {reply, {error, Reason}, State}
%% NewState = state record()
%% Reason = atom() | string()
%%--------------------------------------------------------------------
handle_call({fetch, Id, Query}, From, State) ->
log(State#state.log_fun, debug, "mysql: fetch ~p (id ~p)", [Query, Id]),
case get_next_mysql_connection_for_id(Id, State#state.conn_list) of
{ok, MysqlConn, RestOfConnList} when is_record(MysqlConn, mysql_connection) ->
mysql_conn:fetch(MysqlConn#mysql_connection.conn_pid, Query, From),
%% move this mysql socket to the back of the list
NewConnList = RestOfConnList ++ [MysqlConn],
%% The ConnPid process does a gen_server:reply() when it has an answer
{noreply, State#state{conn_list = NewConnList}};
nomatch ->
%% we have no active connection matching Id
{reply, {error, no_connection}, State}
end;
%%--------------------------------------------------------------------
%% Function: handle_call({add_mysql_connection, Conn}, From, State)
%% Conn = mysql_connection record()
%% Descrip.: Add Conn to our list of connections.
%% Returns : {reply, Reply, NewState}
%% Reply = ok | {error, Reason}
%% NewState = state record()
%% Reason = string()
%%--------------------------------------------------------------------
handle_call({add_mysql_connection, Conn}, _From, State) when is_record(Conn, mysql_connection) ->
case add_mysql_conn(Conn, State#state.conn_list) of
{ok, NewConnList} ->
{Id, ConnPid} = {Conn#mysql_connection.id, Conn#mysql_connection.conn_pid},
log(State#state.log_fun, normal, "mysql: Added connection with id '~p' (pid ~p) to my list",
[Id, ConnPid]),
{reply, ok, State#state{conn_list = NewConnList}};
error ->
{reply, {error, "failed adding MySQL connection to my list"}, State}
end;
%%--------------------------------------------------------------------
%% Function: handle_call(get_logfun, From, State)
%% Descrip.: Fetch our logfun.
%% Returns : {reply, {ok, LogFun}, State}
%% LogFun = undefined | function() with arity 3
%%--------------------------------------------------------------------
handle_call(get_logfun, _From, State) ->
{reply, {ok, State#state.log_fun}, State};
handle_call(Unknown, _From, State) ->
log(State#state.log_fun, error, "mysql: Received unknown gen_server call : ~p", [Unknown]),
{reply, {error, "unknown gen_server call in mysql client"}, State}.
%%--------------------------------------------------------------------
%% Function: handle_cast(Msg, State)
%% Descrip.: Handling cast messages
%% Returns : {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State} (terminate/2 is called)
%%--------------------------------------------------------------------
handle_cast(Unknown, State) ->
log(State#state.log_fun, error, "mysql: Received unknown gen_server cast : ~p", [Unknown]),
{noreply, State}.
%%--------------------------------------------------------------------
%% Function: handle_info(Msg, State)
%% Descrip.: Handling all non call/cast messages
%% Returns : {noreply, State} |
%% {noreply, State, Timeout} |
%% {stop, Reason, State} (terminate/2 is called)
%%--------------------------------------------------------------------
%%--------------------------------------------------------------------
%% Function: handle_info({'DOWN', ...}, State)
%% Descrip.: Handle a message that one of our monitored processes
%% (mysql_conn processes in our connection list) has exited.
%% Remove the entry from our list.
%% Returns : {noreply, NewState} |
%% {stop, normal, State}
%% NewState = state record()
%%
%% Note : For now, we stop if our connection list becomes empty.
%% We should try to reconnect for a while first, to not
%% eventually stop the whole OTP application if the MySQL-
%% server is shut down and the mysql_dispatcher was super-
%% vised by an OTP supervisor.
%%--------------------------------------------------------------------
handle_info({'DOWN', _MonitorRef, process, Pid, Info}, State) ->
LogFun = State#state.log_fun,
case remove_mysql_connection_using_pid(Pid, State#state.conn_list, []) of
{ok, Conn, NewConnList} ->
LogLevel = case Info of
normal -> normal;
_ -> error
end,
log(LogFun, LogLevel, "mysql: MySQL connection pid ~p exited : ~p", [Pid, Info]),
log(LogFun, normal, "mysql: Removed MySQL connection with pid ~p from list",
[Pid]),
case Conn#mysql_connection.reconnect of
true ->
start_reconnect(Conn, LogFun);
false ->
ok
end,
{noreply, State#state{conn_list = NewConnList}};
nomatch ->
log(LogFun, error, "mysql: Received 'DOWN' signal from pid ~p not in my list", [Pid]),
{noreply, State}
end;
handle_info(Info, State) ->
log(State#state.log_fun, error, "mysql: Received unknown signal : ~p", [Info]),
{noreply, State}.
%%--------------------------------------------------------------------
%% Function: terminate(Reason, State)
%% Descrip.: Shutdown the server
%% Returns : Reason
%%--------------------------------------------------------------------
terminate(Reason, State) ->
LogFun = State#state.log_fun,
LogLevel = case Reason of
normal -> debug;
_ -> error
end,
log(LogFun, LogLevel, "mysql: Terminating with reason : ~p", [Reason]),
Reason.
%%--------------------------------------------------------------------
%% Function: code_change(_OldVsn, State, _Extra)
%% Descrip.: Convert process state when code is changed
%% Returns : {ok, State}
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%====================================================================
%% Internal functions
%%====================================================================
%%--------------------------------------------------------------------
%% Function: add_mysql_conn(Conn, ConnList)
%% Conn = mysql_connection record()
%% ConnList = list() of mysql_connection record()
%% Descrip.: Set up process monitoring of the mysql_conn process and
%% then add it (first) to ConnList.
%% Returns : NewConnList = list() of mysql_connection record()
%%--------------------------------------------------------------------
add_mysql_conn(Conn, ConnList) when is_record(Conn, mysql_connection), is_list(ConnList) ->
erlang:monitor(process, Conn#mysql_connection.conn_pid),
{ok, [Conn | ConnList]}.
%%--------------------------------------------------------------------
%% Function: remove_mysql_connection_using_pid(Pid, ConnList)
%% Pid = pid()
%% ConnList = list() of mysql_connection record()
%% Descrip.: Removes the first mysql_connection in ConnList that has
%% a pid matching Pid.
%% Returns : {ok, Conn, NewConnList} | nomatch
%% Conn = mysql_connection record()
%% NewConnList = list() of mysql_connection record()
%%--------------------------------------------------------------------
remove_mysql_connection_using_pid(Pid, [#mysql_connection{conn_pid = Pid} = H | T], Res) ->
{ok, H, lists:reverse(Res) ++ T};
remove_mysql_connection_using_pid(Pid, [H | T], Res) when is_record(H, mysql_connection) ->
remove_mysql_connection_using_pid(Pid, T, [H | Res]);
remove_mysql_connection_using_pid(_Pid, [], _Res) ->
nomatch.
%%--------------------------------------------------------------------
%% Function: get_next_mysql_connection_for_id(Id, ConnList)
%% Id = term(), connection-group id
%% ConnList = list() of mysql_connection record()
%% Descrip.: Find the first mysql_connection in ConnList that has an
%% id matching Id.
%% Returns : {ok, Conn, NewConnList} | nomatch
%% Conn = mysql_connection record()
%% NewConnList = list() of mysql_connection record(), same
%% as ConnList but without Conn
%%--------------------------------------------------------------------
get_next_mysql_connection_for_id(Id, ConnList) ->
get_next_mysql_connection_for_id(Id, ConnList, []).
get_next_mysql_connection_for_id(Id, [#mysql_connection{id = Id} = H | T], Res) ->
{ok, H, lists:reverse(Res) ++ T};
get_next_mysql_connection_for_id(Id, [H | T], Res) when is_record(H, mysql_connection) ->
get_next_mysql_connection_for_id(Id, T, [H | Res]);
get_next_mysql_connection_for_id(_Id, [], _Res) ->
nomatch.
%%--------------------------------------------------------------------
%% Function: start_reconnect(Conn, LogFun)
%% Conn = mysql_connection record()
%% LogFun = undefined | function() with arity 3
%% Descrip.: Spawns a process that will try to re-establish a new
%% connection instead of the one in Conn which has just
%% died.
%% Returns : ok
%%--------------------------------------------------------------------
start_reconnect(Conn, LogFun) when is_record(Conn, mysql_connection) ->
Pid = spawn(fun () ->
reconnect_loop(Conn#mysql_connection{conn_pid = undefined}, LogFun, 0)
end),
{Id, Host, Port} = {Conn#mysql_connection.id, Conn#mysql_connection.host, Conn#mysql_connection.port},
log(LogFun, debug, "mysql: Started pid ~p to try and reconnect to ~p:~s:~p (replacing "
"connection with pid ~p)", [Pid, Id, Host, Port, Conn#mysql_connection.conn_pid]),
ok.
%%--------------------------------------------------------------------
%% Function: reconnect_loop(Conn, LogFun, 0)
%% Conn = mysql_connection record()
%% LogFun = undefined | function() with arity 3
%% Descrip.: Loop indefinately until we are able to reconnect to the
%% server specified in the now dead connection Conn.
%% Returns : ok
%%--------------------------------------------------------------------
reconnect_loop(Conn, LogFun, N) when is_record(Conn, mysql_connection) ->
{Id, Host, Port} = {Conn#mysql_connection.id, Conn#mysql_connection.host, Conn#mysql_connection.port},
case connect(Id,
Host,
Port,
Conn#mysql_connection.user,
Conn#mysql_connection.password,
Conn#mysql_connection.database,
Conn#mysql_connection.reconnect) of
{ok, ConnPid} ->
log(LogFun, debug, "mysql_reconnect: Managed to reconnect to ~p:~s:~p (connection pid ~p)",
[Id, Host, Port, ConnPid]),
ok;
{error, Reason} ->
%% log every once in a while
NewN = case N of
10 ->
log(LogFun, debug, "mysql_reconnect: Still unable to connect to ~p:~s:~p (~p)",
[Id, Host, Port, Reason]),
0;
_ ->
N + 1
end,
%% sleep between every unsuccessfull attempt
timer:sleep(20 * 1000),
reconnect_loop(Conn, LogFun, NewN)
end.