Posts Tagged golang

Extracting amenity tag info from OSM database in 3 simple steps

Step 1. Download the needed OSM database in PBF format from here: planet.openstreetmap.org (be careful, it has huge size, many GBs)

Step 2. Install golang package for for decoding osm pdf files: github.com/qedus/osmpbf

Step 3. Use simple golang program below to decode whatever you need (let’s say you need to find all petrol stations)

Read the rest of this entry »

, , , , , , ,

Leave a comment

Creating ubuntu service for go app

Step 1

Install go program with go install in the app folder

Step 2

Download service script file from here: Service for go app

Step 3

Change {{USERNAME}} in the script to the user you use in ubuntu to run your app and change  {{APPNAME}}  to binary name in your $GOPATH/bin/, if needed fix the path in cmd variable to point to your own $GOPATH folder

Step 4

Rename the service remove ending ‘.sh’ and copy the service file in the folder  /etc/init.d/

Step 5

Run in the terminal chmod 700 /etc/init.d/goappservice

Step 6

Run sudo update-rc.d goappservice defaults

Step 7

Run sudo update-rc.d goappservice enable

Done!

Use usual service commands to work with your new service.

sudo service goappservice start|stop|restart|status

If there is a new version of the app then just run go install in the app folder and restart the service.

Enjoy

, ,

Leave a comment

Sending mail using TLS with Go

As I did not find any example of go program which is sending UTF-8 mail with TLS, I decided to create my own go package with this functionality + example, find more details here: https://github.com/bykovme/tlsmailgo-mascot-mail

 

Mail message can be sent this easy:

 

mail := tlsmail.TLSMail{
	Host:     "mail.your_favorite_hosting_provider.here",  
	Port:     "465",                           
	Sender:   "noreply@mail_from.here",        
	Password: "123456",                        
	TO:       []string{"mail1@mail_to.here"},
	Subject:  subject,                       
	Body:     body,                          
}

err := mail.Send()

if err != nil {
	log.Println("Mail send failure: " + err.Error())
} else {
	log.Println("Mail sent successfully")
}

Enjoy!

, , , , ,

Leave a comment

Fixing not working auto-completion for golang in Visual Studio Code

gophervsMy favorite code editor for GO  (Visual Studio Code with Go extenstion from lukehoban) on my Mac sometimes loses its intelligent behavior when suddenly code completion stops to work.

Usually just couple of commands in terminal recovers auto-completion back to life:

  1. Close Visual Studio Code
  2. Open terminal and stop gocode with gocode close
  3. Update gocode with the command `go get -u github.com/nsf/gocode`
  4. Start Visual Studio Code again and enjoy.

, , , , , ,

Leave a comment

Configure Ubuntu to work as GO web server

Картинки по запросуI’m often creating go apps or services using Digital Ocean droplets with Ubuntu, that’s why I decided to create a script to automate configuration process.

 

The script is doing following:

  1. Installs and configures firewall (ufw, allows only ports 80, 443 & 22)
  2. Installs git (required by go)
  3. Installs mysql and secures it with mysql_install_db
  4. Installs the latest version of GO (1.7.5), configures go environment (PATH, GOPATH)
  5. Installs go application from public git repository, yours or my demo (development for private is in progress) with ‘go get’
  6. Configures go app to work as a service (add config into /etc/init.d), starts the service
  7. Installs and configures nginx to work as proxy for go app

Script can be started directly from github:

bash <(curl -s https://raw.githubusercontent.com/bykovme/webgolangdo/master/preparegolangapp.sh)

Check the script and find more information here: https://github.com/bykovme/webgolangdo

, , , , , , , , , , , , , ,

Leave a comment

Config library for golang

Publishing config library to be used with go, it stores/loads structure as JSON file, so you can use it to keep options of your app: github.com/bykovme/goconfig

Example of using: github.com/bykovme/goconfig/blob/master/example/load_config.go

There are only 5 functions:

  • SaveConfig – saving configuration from structure into the file
  • LoadConfig – loading configuration from file into the structure
  • SearchForConfigFile – search for config file in different locations
  • GetLocalPath – get current path where executable app is running
  • GetUserPath – get user home folder

, , ,

Leave a comment

Localization for GOLANG

I created and published small package to be used for localization of go applications, you can find it here https://github.com/bykovme/gotrans

Installation

Install the package with the command

go get github.com/bykovme/gotrans

Prepare translation files

JSON files should use following format as in the example below:

{
    "hello_world":"Hello World",
    "find_more":"Find more information about the project on the website %s"
}

JSON file name should use standard language code or language-country code supported by browsers, if you are developing web app. At least one file with English locale should be in the localization folder with the name “en.json”.

Quick documentation

There are just 3 functions in the package

InitLocales(path string)

Use the relative or absolute path to set the folder where all the JSON files with translations are located. Make sure that all the files with translations have extension “.json”

Tr(lang string, key string) string

Get translation value by the language & key

DetectLanguage(acceptLanguage string) string

This function will be useful when you are creating web application, it detects the language from HTTP header Accept-Language, check the usage of the function in the example below

Example of using gotrans package

The same example is located within the package here

package main

import (
    "fmt"
    "net/http"

    "github.com/bykovme/gotrans"
)

func handler(w http.ResponseWriter, r *http.Request) {
    lang := gotrans.DetectLanguage(r.Header.Get("Accept-Language"))
    fmt.Fprintf(w, "<html><head><title> %s </title></head><body>", gotrans.Tr(lang, "hello_world"))
    fmt.Fprintf(w, "<h2> %s </h2>", gotrans.Tr(lang, "hello_world"))
    githubLink := "https://github.com/bykovme/gotrans"
    link := fmt.Sprintf(`<a href="%s">%s</a>`, githubLink, githubLink)
    fmt.Fprintf(w, gotrans.Tr(lang, "find_more"), link)
    fmt.Fprint(w, "</body></html>")
}

func main() {
    err := gotrans.InitLocales("langs")
    if err != nil {
        panic(err)
    }

    http.HandleFunc("/", handler)
    http.ListenAndServe(":3000", nil)
}

Behaviour

If the key is not found in the localization file, it will try to find the same key in English localization (“en.json”), if the key is not found there as well, the key will be returned instead of value.

, , , , , ,

Leave a comment