I am using node-redis and having a hard time connecting to external redis instance. I tried with redis-cli and it worked. However with node I am not able to figure out how to properly give the url and port.
With Redis-cli-
redis-cli -h mydomain.something.something.cache.amazonaws.com -p 6379
However with nodejs
Below didn't work
var client = redis.createClient('redis://mydomain.something.something.cache.amazonaws.com:6379'),
neither
var client = redis.createClient({host:'redis://mydomain.something.something.cache.amazonaws.com', port: 6379});
How do I configure it. Please help.
Following should work with node.js -
var client = require('redis').createClient(6379, 'elastichache endpoint string', {
no_ready_check: true
});
Also, make sure that your security group on AWS allows you to access the database.
var client = require('redis').createClient(6379, 'elastichache endpoint string', {
no_ready_check: true
});
With the above code, it was always trying to connect with localhost,
Below code worked for me.
var client = require('redis').createClient(
{
url: `redis://${elasticCacheConnectionString}`,
}
);
Please note, i have appended redis:// as communication protocol before actual connection string.
FYI: I am using redis#4.1.0 version.
Related
I have been researching this for day and I haven't been able to find the way to do this.
I am building a react app, running express at the backend, that needs to access some data in a remote database that lives inside a VPN. At the moment the app lives on my localhost so its enough for me to connect my machine using openvpn client and everything works a beauty. The problem will rise when the app will be live and I will need it to have access to the vpn by (I'm guessing) having a vpn client running on the site/domain.
Has anyone done this before?
I have tried to install the node-openvpn package that seems could do the job but unfortunately I can't manage to make it work as the connection doesn't seem to be configured properly.
This is the function I call to connect to the vpn that systematically fails at the line
--> openvpnmanager.authorize(auth);
const openvpnmanager = require('node-openvpn');
...
const connectToVpn = () => {
var opts = {
host: 'wopr.remotedbserver.com',
port: 1337, //port openvpn management console
timeout: 1500, //timeout for connection - optional,
logpath: '/log.txt'
};
var auth = {
user: 'userName',
pass: 'passWord',
};
var openvpn = openvpnmanager.connect(opts);
openvpn.on('connected', function() {
console.log('connecting..');
openvpnmanager.authorize(auth); <-- Error: Unhandled "error" event. (Cannot connect)
});
openvpn.on('console-output', function(output) {
console.log(output)
});
openvpn.on('state-change', function(state) { //emits console output of openvpn state as a array
console.log(output)
});
};
Am I misusing this function? Is there a better way?
Any help will be extremely appreciated.
Thank You!
The problem will rise when the app will be live and I will need it to
have access to the vpn by (I'm guessing) having a OpenVPN client running
on the site/domain.
Thats correct, you will need an openvpn client instance on the server where you will run the backend.
The above library (node-openvpn) is simply a library to interact with the local OpenVPN client instance. It cannot create a connection on its own. It depends on the OpenVPN binary (which should be running).
The solution you need is simply run the OpenVPN client on your server (apt-get openvpn). And let the daemon run. Check out the references below.
node-openvpn issues that points out that a running instance of the client is needed
OpenVPN CLI tutorial
I have a problem deploying a Nodejs app with a Postgresql database. The database comes from Heroku itself (Heroku Postgres add-on, hobby-dev). My app refused to connect to the database.
I found where the problem came from but I can't find a clean solution. And I think I could have misunderstood something (I'm new to Node and Heroku).
Heroku automatically gives me an environment variable DATABASE_CONFIG that includes the port:
postgres://username:password#hostname:port/databasename
Then, to connect with pg in my app, I use process.env.DATABASE_CONFIG as a connection string. I do something like:
const client = new Client({
connectionString: connectionString,
})
client.connect()
This fails to connect.
But if instead of using this environment variable, I cheat and change it, removing the port number from this connection string, it works.
I don't know why but the problem is that Heroku gives you this DATABASE_URL with the port included and you can't change it.
Did I do something wrong? Is there a clean solution to avoid that?
(because what I did is ugly as I hard-coded the DATABASE_CONFIG without the port directly in my code)
Thanks for your help!
First off, I would avoid using new Client() as this can lead to your connection being bottlenecked. Instead, use connection pooling. You can read a more indepth answer into why you want to do that here.
As for you direct issue, personally I have had trouble connecting to heroku postgres databases in the past, but here is a (basic) typical setup that works for me 99% of the time:
let pg = require('pg');
if (process.env.DATABASE_URL) {
pg.defaults.ssl = true;
}
// include an OR statement if you switch between a local dev db and
// a remote heroku environment
let connString = process.env.DATABASE_URL || 'postgresql://postgres:password#localhost:localpostgresport/yourlocaldbname';
const { Pool } = require('pg');
const pool = new Pool({
connectionString : connString
});
My first guess would be that it may have to do with ssl not being enabled. I know that has cause me problems in the past. Secondly, you want to make sure that you uses the process.env.DATABASE_URL, as environment variable should be set as the postgres connection string by Heroku.
Edit: My issue is now this. I can connect to iot.eclipse.org using http://www.hivemq.com/demos/websocket-client, using port 80. When I connect via a browsified mqtt.js client I am getting the following error :
WebSocket connection to 'ws://iot.eclipse.org/' failed: Error during
WebSocket handshake: Unexpected response code: 200
I've tried ports 8080, 8000, 1883 and 80, without any luck. Any suggestions?
------------ Original question below -----------
I want to connect with a mqtt broker using mqtt over websockets. My client will need to run in a browser.
TO achieve this I am using mqtt.js library and am following these instructions.
Everything works when running against the public broker at broker.mqttdashboard.com. However when I connect to the public brokers at iot.eclipse.org and test.mosquitto.org I get HTTP errors.
I think the problem is incorrect configuration of the client when running against the second two brokers, but I'm struggling to find any help.
Heres the configuration, is there anyone out there who can help me?
// Works fine
var options = {
host: "broker.mqttdashboard.com",
port: 8000
};
// Doesn't work
/*var options = {
host: "m2m.eclipse.org",
protocolId: 'MQIsdp',
protocolVersion: 3
};*/
// Doesn't work
/*var options = {
host: "test.mosquitto.org",
protocolId: 'mosqOtti',
protocolVersion: 3
};*/
var client = mqtt.connect(options);
Let me know if theres any more information you need!
Mark
Both test.mosquitto.org and iot.eclipse.org are both websockets enabled (for a long time now actually).
You already have got test.mosquitto.org working - the key there is using port 8080.
The current iot.eclipse.org configuration expects the connection url to be ws://iot.eclipse.org/mqtt.
I don't think m2m.eclipse.org / iot.eclipse.org or test.mosquitto.org have websockets enabled.
broker.mqttdashboard.com runs a HiveMQ underneath which has native websockets enabled.
So in short, I don't think this is a configuration problem on your side. To make sure, you can check this web application and see if the other brokers work with that: http://www.hivemq.com/demos/websocket-client/
0 version of socket.io and I cannot find reference to the connect() function for the client. The issues I am having is that before I could connect like:
var socket = io.connect(
'localhost',
{
port: 3000,
reconect: true,
'force new connection': true
}
Now this does not work. My server is not getting the 'connect' event. Looking at the io after trying to connect like so noticed that the port number was not on the managers list and the uri was set to https://localhost. If I do io.connect('http://localhost:3000') works. Why is this? Does anyone know of any changes made to the connect that was not listed in the migrating section of the documentation?
Had a look at the sources of 0.9 and 1.0. I can't find anything called opts.reconect (typo?). All I could see was opts.reconnection. Also, I'm not sure what your 'force new connection' option is doing.
Anyway, I tested connecting via var socket = io();, as well as var socket = io.connect('localhost', {port:3000});. Both worked as intended.
I'm using Redis To Go in combination with the https://github.com/mranney/node_redis library. Redis gives me a url that looks like redis://me:978287c0b670694673d045f08b2e0371#icefish.redistogo.com:9393 but I don't know how to use it as createClient() only takes the host and the port.
I believe that the scheme for the URL you have is:
redis://username:password#host:port.
I don't believe username is used. node_redis provides two methods that you'll use to log in: createClient and auth. There are details in the readme, but for reference here is the relevant portion:
redis.createClient(port, host, options)
Create a new client connection. port defaults to 6379 and host
defaults to 127.0.0.1. If you have redis-server running on the
same computer as node, then the defaults for port and host are
probably fine. options in an object with the following possible
properties:
parser: which Redis protocol reply parser to use. Defaults to
hiredis if that module is installed. This may also be set to
javascript.
return_buffers: defaults to false. If set to true, then bulk
data replies will be returned as node Buffer objects instead of
JavaScript Strings.
createClient() returns a RedisClient object that is named client
in all of the examples here.
client.auth(password, callback)
When connecting to Redis servers that require authentication, the
AUTH command must be sent as the first command after connecting.
This can be tricky to coordinate with reconnections, the ready check,
etc. To make this easier, client.auth() stashes password and will
send it after each connection, including reconnections. callback is
invoked only once, after the response to the very first AUTH command
sent.
I also had to add the parameter no_ready_check: true to the call to redis.createClient().
client = redis.createClient(settings.redis.port,
settings.redis.host,
{no_ready_check: true});
if (settings.redis.password) {
client.auth(settings.redis.password, function() {
console.log('Redis client connected');
});
}