DEV Community: vasubabu

Start Goland from terminal

vasubabu — Thu, 27 Aug 2020 16:10:10 +0000

Its Very Easy!!!

Step1:

Open Goland and click on Tools -> Create Command-line launcher and give the path as /usr/local/bin/goland

Step2:

Create an alias
alias goland='/usr/local/bin/goland'

Tip: Its better to have this line a startup script, so that restart doesn't revert your changes

Step 3:

Open terminal and go to your workspace and type
goland .

That's it!!! you will see your IDE opening your favourite project

cmd/go: go mod init fails to determine module path in subdirectory

vasubabu — Thu, 20 Aug 2020 08:11:41 +0000

I know you came for solution as always i don't talk much ;)

Problem:

cmd/go: go mod init fails to determine module path in subdirectory

Solutions:

#1: Update your go path to your current working directory (you can specify multiple)

 export GOPATH="/Users/XXXX/dir1:/Users/XXXX/dir2"

#2: if Plan A not working then Plan B

go mod init <module_name>

Hopefully Plan B works, if not please mention in comment section. i can help you :)

Split/Slice an Array into chunks (golang)

vasubabu — Tue, 14 Jul 2020 14:02:13 +0000

Below code talks more :)

package main

import (
    "fmt"
)

func main() {
    arr := []int{1, 2, 3, 5, 6, 6, 7, 7, 7, 8, 8, 8, 8, 9}
    limit := 5

    for i := 0; i < len(arr); i += limit {
        batch := arr[i:min(i+limit, len(arr))]
        fmt.Println(batch)
    }

}

func min(a, b int) int {
    if a <= b {
        return a
    }
    return b
}

Above code split an array into multiple chunks based on the chunk size.

Why can't i use `math.Min` ?

Because golang Math function mainly supports float64 instead of int and one more disadvantage of golang is not having support of generics

Looks like go is getting support of generics in go 2.0.

https://github.com/golang/go/issues/25597

How to Edit your videos for youtube using iMovie

vasubabu — Thu, 25 Jun 2020 14:52:10 +0000

For any New YouTuber, the biggest hurdle is video editing. In this video, I am going to show you how to edit your videos like a PRO using iMovie

Note: Click on the above page to redirect to youtube

This is a step by step based tutorial, you can directly skip to the respective topic if you don't want to watch the entire video. Please find the timestamps below:

2:12 Import Media
2:36 Add Videos to Timeline
3:14 Adding Voiceover

5:15 Adding Tiles
6:30 Adding Transitions
7:26 Adding Timelapse Effect
9:48 Adding an image (logo)
13:50 Green Screen Effects
17:29 Animation using Keynote
18:53 Animated Intro
21:00 Remove BG Noise
21:47 Export to Media

Solution: Polygons and MultiPolygons should follow the right-hand rule

vasubabu — Thu, 25 Jun 2020 12:41:37 +0000

I use OpenStreetMaps/Datahub.io to get the polygon data for an area.
For Country polygons, I prefer Datahub.io and others I prefer Open street maps.

Links:
https://nominatim.openstreetmap.org/search.php?q=liege&polygon_geojson=1&format=json
Note: Please change q=liege to your desired place and nominatim is the UI built on top of OSM.
Datahub.io

sometimes you may see the below error while validating a Geo-JSON data downloaded using https://geojsonlint.com

Line 1: Polygons and MultiPolygons should follow the right-hand rule

This is because the Geo-JSON data is not following the Right-Hand rule.

What is a Right-Hand rule?

When you construct a polygon, you can order the coordinates in one direction or another. If you’re drawing a circle, you might start on the left and go counter-clockwise around to meet the original point. Or, you might go clockwise.

Here is the specification:

A linear ring MUST follow the right-hand rule with respect to the area it bounds, i.e., exterior rings are counterclockwise, and holes are clockwise.

Source: mapster

Fix: Its very hard to convert the Geo-Json data according to Right hand rule, one way is use this tool to do that

http://mapster.me/right-hand-rule-geojson-fixer/

Geo-JSON Lint:

[Easy]: Truncate a table and restart Sequences (Identity and cascade)

vasubabu — Thu, 18 Jun 2020 07:55:50 +0000

Sometimes you may have to delete or truncate your records in the table for your local or dev testing. Easy way is to do with the below command.

  delete from <table> where <condition> = <value>

This Works!!!

But above command doesn't restart the sequences i.e; IDENTITY and CASCADE associated with table columns.

 TRUNCATE <table_name> RESTART IDENTITY CASCADE;

References:
Stack Overflow

Edit your commit messages in GIT

vasubabu — Fri, 27 Mar 2020 07:15:33 +0000

Sometimes intentionally or unintentionally you may have given a wrong commit message due to various reasons.

But don't worry...

You can change your commit messages with GIT rebase command.

Step 1: Checkout Branch

checkout your branch where you want to change your commit messages

   git checkout <branch>

Step2: Pull last N commits

Rebase will help you modify your commit messages, squash and merge all your commits into one, but this tutorial is mainly to edit your messages. I will talk more about rebase in another tutorial.

   git rebase -i HEAD~N

display a list of the lastNcommits in your default text editor.

Step3: Long live `Reword`

Replace pick with reword before each commit message you want to change.

Step 4: Use force sometimes

git push -f origin <branch>

Step 5: Have a break !!!!

Solution: UnSupported Protocol scheme golang issue

vasubabu — Thu, 05 Dec 2019 06:03:55 +0000

Recently I had faced an issue while using net/http to get the resource from an URL:

Here is my program:

package main

import (
    "fmt"
    "log"
    "net/http"
)

type WebScrapper interface {
    PullContent(url string)
}

type webScrapper struct {
}

func (w *webScrapper) PullContent(url string) {
    resp, err := http.Get(url)

    if err != nil {
        panic(err)
    }

    defer (func() {
        if r := recover(); r != nil {
            fmt.Printf("Recovered from panic %s", r)
        }
    })()

    log.Printf("Got response for %s and status is %s", url, resp.Status)
}

func main() {
    w := webScrapper{}
    urls := []string{
        "www.google.com",
        "www.facebook.com",
        "www.gmail.com",
    }

    for i := 0; i < len(urls); i++ {
        w.PullContent(urls[i])
    }

}

yes its a lot of code, but don't worry about code having interfaces and structs and defer. The code is breaking mainly at getting resource from URL.

Error:

 Get www.google.com: unsupported protocol scheme ""

Solution:

To fix unsupported protocol scheme prepend http:// before every URL.

urls := []string{
        "http://www.google.com",
        "http://www.facebook.com",
        "http://www.gmail.com",
    }

That's it!!!

How to POST multipart/form-data in GO using Mux

vasubabu — Mon, 04 Nov 2019 16:42:21 +0000

Mux is a powerful HTTP router that matches incoming requests against a list of registered routes and calls a handler for the route that matches the URL or other conditions.

Enough talking ....

Please create a new file called main.go and paste the below contents



package main

import (
    "fmt"
    "github.com/gorilla/mux"
    "io"
    "log"
    "net/http"
    "os"
)

func UploadFile(w http.ResponseWriter, r *http.Request) {
    file, handler, err := r.FormFile("file")
    fileName := r.FormValue("file_name")
    if err != nil {
        panic(err)
    }
    defer file.Close()

    f, err := os.OpenFile(handler.Filename, os.O_WRONLY|os.O_CREATE, 0666)
    if err != nil {
        panic(err)
    }
    defer f.Close()
    _, _ = io.WriteString(w, "File "+fileName+" Uploaded successfully")
    _, _ = io.Copy(f, file)
}

func homeLink(w http.ResponseWriter, r *http.Request) {
    _, _ = fmt.Fprintf(w, "Welcome home!")
}

func main() {
    router := mux.NewRouter().StrictSlash(true)
    router.HandleFunc("/", homeLink)
    router.HandleFunc("/file", UploadFile).Methods("POST")
    log.Fatal(http.ListenAndServe(":8081", router))
}

Build it - go build

Run it - go run main.go

Test it - Using Postman/Curl

Postman:

CURL:



curl -X POST \
  http://localhost:8081/file \
  -H 'Accept: */*' \
  -H 'Accept-Encoding: gzip, deflate' \
  -H 'Cache-Control: no-cache' \
  -H 'Connection: keep-alive' \
  -H 'Content-Length: 4251' \
  -H 'Content-Type: multipart/form-data; boundary=--------------------------489143350034706567613009' \
  -H 'Host: localhost:8081' \
  -H 'Postman-Token: fea94e80-8294-4f0b-87bf-09b706eddac8,1bbb735b-f88d-4194-a1b5-f8cd90189545' \
  -H 'User-Agent: PostmanRuntime/7.17.1' \
  -H 'cache-control: no-cache' \
  -H 'content-type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW' \
  -F file=@/Users/vasubabujinagam/Documents/protobuf-3.9.2/CONTRIBUTORS.txt \
  -F file_name=file1

Customize Fish Shell

vasubabu — Fri, 01 Nov 2019 10:16:04 +0000

Recently I got a chance to taste the fish and I must say it's awesome even though I am totally into bash till now. This Fish Shell is a fully-equipped command line shell that is smart and user-friendly.

There are multiple reasons to say that it is the best tool and some of them are:

Intelligent Auto Suggestions
Themes support
Scripting support - Let's talk about it more!!!

You can find a hell number of articles about this, but I wanted to stress more on customizing your existing Fish shell.

One of my biggest questions when I initially started using Fish was how to migrate my existing bash profile to Fish Shell?.

The answer is Fairly Simple - Easy peasy!!!

`~/bash_profile:`

alias idea='open -a "`ls -dt /Applications/GoLand.app|head -1`"'
export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_171.jdk/Contents/Home

function .runElasticSearch() {
  docker run -p 9200:9200 -p 9300:9300 --name elastic -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:7.4.0

docker run --link elastic:elasticsearch -p 5601:5601 {docker-repo}:{version}

}

function .runZookeeper() {
  cd /Users/vasubabujinagam/Documents/softwares/zookeeper/bin
  ./zkServer.sh start
}

function .stopZookeeper() {
   cd /Users/vasubabujinagam/Documents/softwares/zookeeper/bin
  ./zkServer.sh stop
}

function .runKafka() {
  cd /Users/vasubabujinagam/Documents/softwares/kafka_2.11
  ./bin/kafka-server-start.sh config/server.properties
}

This is how fish functions looks like:

`Fish: ~/.config/fish/config.fish`

alias idea='open -a "`ls -dt /Applications/GoLand.app|head -1`"'

set -x JAVA_HOME /Library/Java/JavaVirtualMachines/jdk1.8.0_171.jdk/Contents/Home 

function .runElasticSearch
  docker run -p 9200:9200 -p 9300:9300 --name elastic -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:7.4.0

docker run --link elastic:elasticsearch -p 5601:5601 {docker-repo}:{version}
end

function .runZookeeper 
  cd /Users/vasubabujinagam/Documents/softwares/zookeeper/bin
  ./zkServer.sh start
end

function .stopZookeeper 
   cd /Users/vasubabujinagam/Documents/softwares/zookeeper/bin
  ./zkServer.sh stop
end

function .runKafka() 
  cd /Users/vasubabujinagam/Documents/softwares/kafka_2.11
  ./bin/kafka-server-start.sh config/server.properties
end

You can see there are not much differences from Bash to Fish. Happy Fishing!!!

Upgrading GO version to 1.13 is not a cakewalk!!!

vasubabu — Wed, 16 Oct 2019 11:04:58 +0000

Why?

Be aware that upgrading the version of Go from older versions to 1.13 is not so easy, it comes with new difficulties due to these recent changes:

Version validation:
- In 1.13 Go performs additional validation on the requested version string. The +incompatible version annotation bypasses the requirement of semantic import versioning for repositories that predate the introduction of modules. The go command now verifies that such a version does not include an explicit go.mod file. Refer for more info https://golang.org/doc/go1.13#/version-validation
Changes to the Environment Variable https://golang.org/doc/go1.13#/proxy-vars
Proxy Servers:
- If your company having private repositories then you need to set these below environment variables
  - go env -w GONOSUMDB="****" # use your github or bitbucket repo base url
  - go env -w GONOPROXY="****" # use your github or bitbucket repo base url
  - go env -w GOPROXY="https://proxy.golang.org,direct" #this should already be the default
  - go env -w GOPRIVATE="****" # use your github or bitbucket repo base url

Before start upgrading first clean your mod cache:
GO111MODULE=on go clean -modcache

I will be listing out the possible errors and it's respective solutions as well.

#1: If you are using go-micro framework

go: bitbucket.org/****/**** requires
    github.com/micro/go-plugins@v0.25.0 requires
    gocloud.dev@v0.10.0 requires
    contrib.go.opencensus.io/exporter/ocagent@v0.4.2 requires
    github.com/census-instrumentation/opencensus-proto@v0.1.0-0.20181214143942-ba49f56771b8: invalid pseudo-version: version before v0.1.0 would have   negative patch number

fix:

Add this at last in your `go.mod` file
replace github.com/census-instrumentation/opencensus-proto v0.1.0-0.20181214143942-ba49f56771b8 => github.com/census-instrumentation/opencensus-proto v0.0.3-0.20181214143942-ba49f56771b8

#2: `Protobuf` related problems

go: k8s.io/api@v0.0.0-20190726022912-69e1bce1dad5 requires
    github.com/gogo/protobuf@v0.0.0-20190410021324-65acae22fc9: invalid pseudo-version: revision is shorter than canonical (65acae22fc9d)
S

fix:

Add this at last in your `go.mod` file
replace github.com/gogo/protobuf v0.0.0-20190410021324-65acae22fc9 => github.com/gogo/protobuf v0.0.0-20190723190241-65acae22fc9d

#3: `github.com/instana/go-sensor` related

fix:

Add this at last in your `go.mod` file
replace github.com/instana/go-sensor => github.com/instana/golang-sensor v1.5.0

#4: Issue with `mailgun-go`

fix:

Add this at last in your `go.mod` file
replace github.com/mailgun/mailgun-go => github.com/mailgun/mailgun-go v0.0.0-20180718145431-bbe57f98d550

#5: Issue with `hashicorp` ambiguous import issue

cannot load github.com/hashicorp/consul/api: ambiguous import: found github.com/hashicorp/consul/api in multiple modules:
        github.com/hashicorp/consul v1.4.4 (/Users/vasubabujinagam/go/pkg/mod/github.com/hashicorp/consul@v1.4.4/api)
        github.com/hashicorp/consul/api v1.1.0 (/Users/vasubabujinagam/go/pkg/mod/github.com/hashicorp/consul/api@v1.1.0)
S

fix:

Add this at last in your `go.mod` file
replace github.com/hashicorp/consul => github.com/hashicorp/consul v1.5.1

if you are facing anything other than this, please post in the comment section.

DEV Community: vasubabu

Start Goland from terminal

Step1:

Step2:

Step 3:

cmd/go: go mod init fails to determine module path in subdirectory

Problem:

Solutions:

Split/Slice an Array into chunks (golang)

Why can't i use math.Min ?

How to Edit your videos for youtube using iMovie

Solution: Polygons and MultiPolygons should follow the right-hand rule

What is a Right-Hand rule?

Here is the specification:

[Easy]: Truncate a table and restart Sequences (Identity and cascade)

Edit your commit messages in GIT

Step 1: Checkout Branch

Step2: Pull last N commits

Step3: Long live Reword

Step 4: Use force sometimes

Step 5: Have a break !!!!

Solution: UnSupported Protocol scheme golang issue

How to POST multipart/form-data in GO using Mux

Postman:

CURL:

Customize Fish Shell

~/bash_profile:

Fish: ~/.config/fish/config.fish

Upgrading GO version to 1.13 is not a cakewalk!!!

Why?

#1: If you are using go-micro framework

fix:

#2: Protobuf related problems

fix:

#3: github.com/instana/go-sensor related

fix:

#4: Issue with mailgun-go

fix:

#5: Issue with hashicorp ambiguous import issue

fix:

Why can't i use `math.Min` ?

Step3: Long live `Reword`

`~/bash_profile:`

`Fish: ~/.config/fish/config.fish`

#2: `Protobuf` related problems

#3: `github.com/instana/go-sensor` related

#4: Issue with `mailgun-go`

#5: Issue with `hashicorp` ambiguous import issue