Problem related to EMQ dashboard

Dear Ravi,
I was following your last tutorial on MQTT.


I am facing problem regarding accessing the EMQ dashboard using http://18.221.232.141:18083/ but I get this error.
What could be the possible reason?

[Fiddler] The connection to ‘18.221.232.141’ failed.
Error: ConnectionRefused (0x274d).
System.Net.Sockets.SocketException No connection could be made because the target machine actively refused it 18.221.232.141:18083

Regards,
Usman Ashraf

@RaviPujar, can you share the complete emq_plugin_template.er1? I think I am making some mistake in that file.

I tried to connect to your broker on 1883 port. It is not able to connect. Are you sure your broker is up and running?

Plugin code you asked :

%%--------------------------------------------------------------------
%% Copyright (c) 2013-2018 EMQ Enterprise, Inc. (http://emqtt.io)
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%--------------------------------------------------------------------

-module(emq_plugin_template).

-include_lib("emqttd/include/emqttd.hrl").

-export([load/1, unload/0]).

%% Hooks functions

-export([on_client_connected/3, on_client_disconnected/3]).

-export([on_client_subscribe/4, on_client_unsubscribe/4]).

-export([on_session_created/3, on_session_subscribed/4, on_session_unsubscribed/4, on_session_terminated/4]).

-export([on_message_publish/2, on_message_delivered/4, on_message_acked/4]).

%% Called when the plugin application start
load(Env) ->
    emqttd:hook('client.connected', fun ?MODULE:on_client_connected/3, [Env]),
    emqttd:hook('client.disconnected', fun ?MODULE:on_client_disconnected/3, [Env]),
    emqttd:hook('client.subscribe', fun ?MODULE:on_client_subscribe/4, [Env]),
    emqttd:hook('client.unsubscribe', fun ?MODULE:on_client_unsubscribe/4, [Env]),
    emqttd:hook('session.created', fun ?MODULE:on_session_created/3, [Env]),
    emqttd:hook('session.subscribed', fun ?MODULE:on_session_subscribed/4, [Env]),
    emqttd:hook('session.unsubscribed', fun ?MODULE:on_session_unsubscribed/4, [Env]),
    emqttd:hook('session.terminated', fun ?MODULE:on_session_terminated/4, [Env]),
    emqttd:hook('message.publish', fun ?MODULE:on_message_publish/2, [Env]),
    emqttd:hook('message.delivered', fun ?MODULE:on_message_delivered/4, [Env]),
    emqttd:hook('message.acked', fun ?MODULE:on_message_acked/4, [Env]).

on_client_connected(ConnAck, Client = #mqtt_client{client_id = ClientId}, _Env) ->
    io:format("client ~s connected, connack: ~w~n", [ClientId, ConnAck]),
    {ok, Client}.

on_client_disconnected(Reason, _Client = #mqtt_client{client_id = ClientId}, _Env) ->
    io:format("client ~s disconnected, reason: ~w~n", [ClientId, Reason]),
    ok.

on_client_subscribe(ClientId, Username, TopicTable, _Env) ->
    io:format("client(~s/~s) will subscribe: ~p~n", [Username, ClientId, TopicTable]),
    {ok, TopicTable}.

on_client_unsubscribe(ClientId, Username, TopicTable, _Env) ->
    io:format("client(~s/~s) unsubscribe ~p~n", [ClientId, Username, TopicTable]),
    {ok, TopicTable}.

on_session_created(ClientId, Username, _Env) ->
    io:format("session(~s/~s) created.", [ClientId, Username]).

on_session_subscribed(ClientId, Username, {Topic, Opts}, _Env) ->
    io:format("session(~s/~s) subscribed: ~p~n", [Username, ClientId, {Topic, Opts}]),
    {ok, {Topic, Opts}}.

on_session_unsubscribed(ClientId, Username, {Topic, Opts}, _Env) ->
    io:format("session(~s/~s) unsubscribed: ~p~n", [Username, ClientId, {Topic, Opts}]),
    ok.

on_session_terminated(ClientId, Username, Reason, _Env) ->
    io:format("session(~s/~s) terminated: ~p.", [ClientId, Username, Reason]).

%% transform message and return
on_message_publish(Message = #mqtt_message{topic = <<"$SYS/", _/binary>>}, _Env) ->
    {ok, Message};

on_message_publish(Message, _Env) ->
    io:format("publish ~s~n", [emqttd_message:format(Message)]),

DeviceIdBin = element(12, Message),
DeviceIdStr = binary_to_list(DeviceIdBin),
inets:start(),
Method = post,
URL = "http://127.0.0.1/api/v2/mysql/_table/log",
Header = [{"X-DreamFactory-Api-Key", "7d1a4baac442ed875b1545af24f9f4312a1cfdb3fad0db096db91cf2869d17f2"}],
Type = "application/json",
Body = DeviceIdStr,%%"{\"resource\":[{\"devid\":\"" ++ DeviceIdStr ++ "\"}]}",
HTTPOptions = [],
Options = [],
R = httpc:request(Method, {URL, Header, Type, Body}, HTTPOptions, Options),
    {ok, Message}.

on_message_delivered(ClientId, Username, Message, _Env) ->
    io:format("delivered to client(~s/~s): ~s~n", [Username, ClientId, emqttd_message:format(Message)]),
    {ok, Message}.

on_message_acked(ClientId, Username, Message, _Env) ->
    io:format("client(~s/~s) acked: ~s~n", [Username, ClientId, emqttd_message:format(Message)]),
    {ok, Message}.

%% Called when the plugin application stop
unload() ->
    emqttd:unhook('client.connected', fun ?MODULE:on_client_connected/3),
    emqttd:unhook('client.disconnected', fun ?MODULE:on_client_disconnected/3),
    emqttd:unhook('client.subscribe', fun ?MODULE:on_client_subscribe/4),
    emqttd:unhook('client.unsubscribe', fun ?MODULE:on_client_unsubscribe/4),
    emqttd:unhook('session.created', fun ?MODULE:on_session_created/3),
    emqttd:unhook('session.subscribed', fun ?MODULE:on_session_subscribed/4),
    emqttd:unhook('session.unsubscribed', fun ?MODULE:on_session_unsubscribed/4),
    emqttd:unhook('session.terminated', fun ?MODULE:on_session_terminated/4),
    emqttd:unhook('message.publish', fun ?MODULE:on_message_publish/2),
    emqttd:unhook('message.delivered', fun ?MODULE:on_message_delivered/4),
    emqttd:unhook('message.acked', fun ?MODULE:on_message_acked/4).

How can I check that the broker is up and running?

By connecting to it using MQTTFx or any other client software.
I execute a command to turn on the broker, if you observe carefully. I edited that part a little fast, you need to check the part of the video where i fail to connect initially and then i execute it. You should issue the command START to the emqttd executable in _rel folder.

Yes, this was the exact mistake that causing problem. The EMQ software was although installed but not running. Using the start command resolves the issue. Thanks.

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