I'm trying to connect to Gremlin which should be running on port 8182 ([INFO] GremlinServer$1 - Channel started at port 8182)
When I'm connecting to: ws://127.0.0.1:8182 I'm getting the response:
2017/11/03 17:20:04 ERROR: database with the name 'gremlin' gave an error when connecting: websocket: bad handshake.
The Gremlin server responds with:
[WARN] HttpGremlinEndpointHandler - Invalid request - responding with 400 Bad Request and no gremlin script supplied
I'm using Gorilla Websocket in Go to connect:
gremlinGrpcAddress := fmt.Sprintf("ws://%s:%d/", f.config.Host, f.config.Port)
var dialer *websocket.Dialer
clientConn, _, err := dialer.Dial(gremlinGrpcAddress, nil)
if err != nil {
return err
}
f.client = clientConn
UPDATE:
Connecting to echo.websocket.org works, so somehow it is something in the Gremlin server.
The answer lies in the config YAML file.
What is needed is the correct channelizer.
GOOD:
channelizer: org.apache.tinkerpop.gremlin.server.channel.WebSocketChannelizer
Connect to ws://localhost:8182/gremlin instead of ws://localhost:8182. There are several references to it in the Apache TinkerPop documentation and the go-gremlin README.
Related
I have no trouble connecting go pgxpool to a postgresql database in a docker container but can't figure out how to write a connection URL string for a linode postgresql RDS. Specifically, what is the first part of the URL "postgres://"? I can't find any example for a connection URL other than a local db and no code examples for a DSN connection.
Can somebody please help me out with either a connection URL or DSN for these details?
Here is my current connection string which returns "host is invalid". ssl_mode is also invalid.
config, err := pgxpool.ParseConfig("user=linpostgres, password=secret, host=lin-9930-2356-pgsql-primary.servers.linodedb.net, port=5432 dbname=mydb, pool_max_conns=10")
This psq connect string times out: psql --username=linpostgres --host=lin-9930-2356-pgsql-primary.servers.linodedb.net port=5432 --password
You can check the code official GitHub repository code here: link
// See Config for definitions of these arguments.
//
// # Example DSN
// user=jack password=secret host=pg.example.com port=5432 dbname=mydb sslmode=verify-ca pool_max_conns=10
//
// # Example URL
// postgres://jack:secret#pg.example.com:5432/mydb?sslmode=verify-ca&pool_max_conns=10
so your connection string should be
postgres://jack:secret#pg.example.com:5432/mydb?sslmode=verify-ca&pool_max_conns=10
hope this helps
I am working on a project where I need to use gomobile tool to create an Android app.
The sample code I have in Go is as below
var broker = "127.0.0.1"
//var broker = "broker.mqttdashboard.com"
var port = 1883
opts := mqtt.NewClientOptions()
opts.AddBroker(fmt.Sprintf("tcp://%s:%d", broker, port))
opts.SetClientID("go_mqtt_client")
opts.SetConnectionLostHandler(connectLostHandler) // define what to do when connection is lost
client := mqtt.NewClient(opts)
tokenClient := client.Connect()
if tokenClient.Wait() && tokenClient.Error() != nil {
panic(tokenClient.Error())
}
...
When I bind this code using "gomobile bind", generating the Golang plugin and calling them inside the android project there is no issue.
Connections is satisfied and I can verify the local mqtt broker (mosquitto) and the mqtt client app are communicating as well.
But when I generate the APK file using "gomobile build -target=android", the connect function generates and error.
To be able to test the logs i used a public broker instead of the local mqtt broker. I replaced the
var broker = "127.0.0.1"
by the HiveMQ public broker address (I have already validated the public broker functionality)
var broker = "broker.mqttdashboard.com"
It seems like there is an issue with connecting from mqtt client app to mqtt broker. Here is the exact error message I found in logs:
E/Go: panic: network Error : dial tcp: lookup
broker.mqttdashboard.com: No address associated with hostname
goroutine 11 [running]: E/GoLog: panic: network Error : dial tcp: lookup broker.mqttdashboard.com: No address associated with hostname
E/Go: main.starting()
This is generated by "panic(tokenClient.Error())" part in my code.
Any idea why the connection is not settled using "gomobile build", while it is working when I use "gomobile bind" ?
Here is how I could fix the issue.
I added the AndoridManifest.xml file to the same directory that the main go package is.
Added the following line in between the manifest tags (<manifest> )
<uses-permission android:name="android.permission.INTERNET">
I'm trying to deploy a Go backend on Google App Engine, connecting to CloudSQL. Deploy magic is working, but when I try to call the API, I get a 500 status:
Error: Server Error
The server encountered an error and could not complete your request.
Please try again in 30 seconds.
When running gcloud app logs tail -s default, I have:
2020/06/07 21:39:26 server.go:52: dial unix /cloudsql/: connect: is a directory
var dbURI string
dbURI = fmt.Sprintf("%s:%s#unix(/cloudsql/%s)/%s", dbUser, dbPwd, dbHost, dbName)
// Open database connection
db, err := gorm.Open(
"mysql",
dbURI,
)
if err != nil {
log.Fatal(err) <-- line 52
}
My app.yaml is setup correctly (I think..):
env_variables:
CLOUDSQL_CONNECTION_NAME: 'XXXXX:europe-west1:XXXXXX'
DB_USER: 'root'
DB_PASS: 'XXXXX'
DB_NAME: 'XXXXX'
Any help would be appreciated :)
I was indeed not using the right ENV variable.. Thank you for pointing that out #Muffin Top
I got below error, I am using go v1.10.4 linux/amd64.
I am not behind any firewall or whatsoever. New Relic in java server (same network segment) that we have runs fine.
We have tried:
Increasing the timeout to 60 seconds
Use http2 in the server
Using Postman return 503 with response:
{"exception":{"message":"Server Error","error_type":"RuntimeError"}}
troubleshooting with ./nrdiag says “No Issues Found”
Below is our code:
config := newrelic.NewConfig(os.Getenv("NEW_RELIC_APP_NAME"), os.Getenv("NEW_RELIC_KEY"))
config.Logger = newrelic.NewDebugLogger(os.Stdout)
app, err := newrelic.NewApplication(config)
if err != nil {
fmt.Println("Failed to create newrelic application", err)
os.Exit(1)
}
.................
httpListener, err := net.Listen("tcp", *httpAddr)
if err != nil {
oldlog.Print("Error: ", err)
logger.Log("transport", "HTTP", "during", "Listen", "err", err)
os.Exit(1)
}
g.Add(func() error {
logger.Log("transport", "HTTP", "addr", *httpAddr)
return http.Serve(httpListener, nrgorilla.InstrumentRoutes(httpHandler, app))
}, func(error) {
httpListener.Close()
})
}
However this what we got,note some_key was removed:
(28422) 2019/07/29 18:08:50.058559 {"level":"warn","msg":"application connect failure","context":{"error":"Post https://collector-001.eu01.nr-data.net/agent_listener/invoke_raw_method?license_key=some_key\u0026marshal_format=json\u0026method=connect\u0026protocol_version=17: net/http: request canceled (Client.Timeout exceeded while awaiting headers)"}}
I think it is due to DNS network timeout.
You can easily test this out by using the following steps (in Ubuntu)
Select the IPv4 Settings tab.
Disable the “Automatic” toggle switch and enter the DNS resolvers' IP addresses, separated by a comma. We’ll use the Google DNS nameservers:
8.8.8.8,8.8.4.4
If it works, then you may be able to reset the DNS to "Automatic"
On Windows OS, Running Linux Containers with WSL2, i followed the following steps,
Ran the command docker logout
Ran the command, docker network prune, so as to remove all the preconfigured settings of the network.
From Docker Settings, Enabled the DNS server configuration with 8.8.8.8
Restarted the Docker
Now executed login command with registry to login, docker login {registry}
I am trying to create Golang web-pages...
Progress:
Ubuntu 18.04 installed both locally and on a Linode VPS.
Created and compiled a local Golang "Hello World" script that renders OK both locally and online.
Created a net/http Golang script that works OK when called locally http://localhost:8080/testing to see if it works
Uploaded the script to the Linode server and initial status messages appear but when calling http:123.456.789.32:8080/testing to see if it works the browser freezes.
//
// Golang - main.go
//
package main
import (
"net/http"
)
func sayHello(w http.ResponseWriter, r *http.Request) {
message := r.URL.Path
message = "Hello " + message
w.Write([]byte(message))
}
func main() {
http.HandleFunc("/", sayHello)
if err := http.ListenAndServe(":8080", nil); err != nil {
panic(err)
}
}
There are no errors or warnings rendered and unable to find any log references.
Can error and warnings similar to PHP error_reporting(-1), declare(strict_types=1) etc be logged or rendered?
A quick check with Nmap showed this result:
nmap -sV -p 8080 <yourIP>
Starting Nmap 7.70 ( https://nmap.org ) at 2019-07-04 07:45 CEST
Nmap scan report for <your-domain>.com (<yourIP>)
Host is up (0.032s latency).
PORT STATE SERVICE VERSION
8080/tcp filtered http-proxy
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 0.90 seconds
The state of "filtered" actually means that there was no response on that port as opposed to an outright rejection of the request.
Check the output of iptables -L -n. Presumably, you have a firewall running and blocking port 8080. Do not simply deactivate the firewall, but read up on how to open port 8080 in the firewall product you are using. Linode has guides for the commonly used/preinstalled firewalls of various Linux distributions.
If you plan to go into production, please have someone help you to ensure security and availability of your deployment.