Nolan's blog

Back to blogging

Wed, 31 Mar 2021 20:35:29 -0700

First blog post on my new blog!

Multiple gitconfigs

Wed, 05 Mar 2025 00:00:00 +0000

git

Mocking Http requests in go

Mon, 10 Apr 2023 00:00:00 +0000

Mocking http retries behavior

As we know, http requests can fail for a large variety of reasons, client side or server side (unauthorized, timeouts etc).
On the client side a common approach is to retry request by increasing the waiting time between retries.

Is this scenario be easily unit test?

Unit Testing

In golang there is this cool library

Simple mocking of an http endpoint:

func TestMockHttpResponse(t *testing.T) {
	httpmock.Activate()
	defer httpmock.DeactivateAndReset()

    httpmock.RegisterResponder("GET", "http://example.com/articles", httpmock.NewStringResponder(200, "my articles").String()))
    resp, err := http.Get("http://example.com/") // return http 200
    ...
}

But there is more, we can actually easily mock retries like this below:

Monkey Patching in Golang

Tue, 27 Sep 2022 00:00:00 +0000

Testing

Golang, Adding static content in binaries

Fri, 09 Sep 2022 00:00:00 +0000

Embed directive

When building a binary, if you load config files, they won’t be added to your binary automatically. (The embed package was added in golang 1.16 before then some external libraries could be used). You have to specifically tell the compiler to add them, by using embed.

import _ "embed"
//go:embed my_config.yaml
var config string

From what I’ve seen, it cannot be done in a function it has to be global. It can also work on multiple files, by using a wildcard, as seen in the documentation

Bulding GPG on Amazon linux from source

Sat, 06 Aug 2022 00:00:00 +0000

Building GPG

Adding service DB in Github action

Sat, 05 Mar 2022 00:00:00 +0000

This is so useful for testing purposes, plus it’s getting easier to do so.
Let’s take a look for PostgreSQL and MySQL.

Adding PostgreSQL in Github action

name: Build
on: push
jobs:
  build:
    runs-on: ubuntu-latest
    services:
    # Label used to access the service container
      postgres:
        # Docker Hub image
        image: postgres:13
        # Provide the password for postgres
        env:
          POSTGRES_USER: root
          POSTGRES_PASSWORD: test
          POSTGRES_DB: sqljson
        # Set health checks to wait until postgres has started
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5          
        ports:
         - 5432:5432
    steps:
      - uses: actions/checkout@v2
      - name: Setup go
        uses: actions/setup-go@v2
        with:
          go-version: ^1.17
      - name: Install go migrate
        run: | 
          curl -L https://github.com/golang-migrate/migrate/releases/download/v4.15.1/migrate.linux-amd64.tar.gz | tar xvz;
          sudo mv migrate /usr/bin/migrate
      - name: Run migration
        run: migrate -path db/migration -database "postgresql://root:test@localhost:5432/sqljson?sslmode=disable" -verbose up
      - run: go test -v ./...

Adding MySQL in Github action

I wanted to do the exact same for MySQL but it’s even simpler because mysql is already present, you just need to start it.

Sending a slow request

Wed, 23 Feb 2022 00:00:00 +0000

Sending a slow request in golang

Using Variadic in Go

Sun, 03 Oct 2021 00:00:00 +0000

Getting dependencies via goproxy

Go testing

Sat, 02 Oct 2021 00:00:00 +0000

Testing in golang

Simple test in go

package main

import "testing"

func add(a, b int) int {
	return a + b
}

func TestAddingNumber(t *testing.T) {
	res := add(1, 7)
	if res != 8 {
		t.Errorf("Sum is incorrect, got: %d, expected: %d", res, 8)
	}
}

Run tests:

go test -v ./...

Avoiding repeating tests

Instead of duplicating code for similar tests, there is a different way to test.

package main

import (
	"strings"
	"testing"
)

func rep(s string) string {
	return strings.Replace(s, "b", "c", -1)
}
func TestFiles(t *testing.T) {
	tests := []struct {
		testName     string
		oldConfigVal string
		newConfigVal string
		err          error
	}{
		{"Testing First config",
			`a:b`,
			`a:c`,
			nil},
		{"Tesing second config",
			`e:f`,
			`e:f`,
			nil},
	}
	t.Run("Test config replaced correctly", func(t *testing.T) {
		for _, tc := range tests {
			t.Run(tc.testName, func(t *testing.T) {
				res := rep(tc.oldConfigVal)
				t.Log(res, tc.newConfigVal)
				if res != tc.newConfigVal {
					t.Errorf("unable to read file")
				}
			})
		}
	})
}

Golang Encoding/Decoding JSON

Sat, 25 Sep 2021 00:00:00 +0000

Encoding JSON

Encoding Decoding is not as straight forward as other languages as it needs to be mapped to a struct.
Or a generic map[interface] can be used if you don’t know the type in advance.

package main

import (
    "encoding/json"
    "fmt"
)

type Data struct {
    Id int `json:"id"`
    List []string `json:"list"`
    NotPrint string `json:"-"`
}


func main(){
    d := Data{Id: 123, List: []string{"abc", "b"},  NotPrint: "This won't print"}
    result, err := json.MarshalIndent(d, "","\t")
    if err != nil {
        panic(err)
    }
    fmt.Printf("%s\n", result)
}

Decoding JSON

package main

import (
    "encoding/json"
    "fmt"
)

type Data struct {
    Id int `json:"id"`
    List []string `json:"list"`
    NotPrint string `json:"-"`
}


var b = []byte(`
  {
    "id" : 123,
    "list": ["a", "b", "c"]
   }
`)


func main() {
   var d Data
   valid := json.Valid(b)
   if valid {
    json.Unmarshal(b, &d)
    fmt.Printf("%#v", d)
   }

}

Go templates

Fri, 24 Sep 2021 00:00:00 +0000

Templating

PostgreSQL in Docker

Tue, 21 Sep 2021 00:00:00 +0000

Up and running DB in seconds

Using multiple versions of the same library

Mon, 06 Sep 2021 00:00:00 +0000

Golang vs Python

Visual Studio

Fri, 03 Sep 2021 00:00:00 +0000

Things I keep forgetting

Tickers

Mon, 30 Aug 2021 00:00:00 +0000

Tickers

Check for misspelled words

Tue, 27 Apr 2021 00:00:00 +0000

Testing client9 misspell

Using GOPROXY

Mon, 19 Apr 2021 00:00:00 +0000

Getting dependencies via goproxy

Golang code coverage badge in gitlab

Fri, 16 Apr 2021 00:00:00 +0000

Broken link checker

Monitoring golang web app with Datadog

Thu, 15 Apr 2021 00:00:00 +0000

Broken link checker

First golang project

Fri, 09 Apr 2021 00:00:00 +0000

First few lines

First few lines in golang

Mon, 05 Apr 2021 00:00:00 +0000

First few lines

Check broken links in Markdown

Sun, 04 Apr 2021 00:00:00 +0000

Broken link checker

Pandas meets SQL

Wed, 03 Mar 2021 00:00:00 +0000

Exploring data with SQL (pysql)