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Merge pull request #1 from janzenbupa/golang
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Added a short page about connecting to dynamodb with golang.
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@janzenbupa
janzenbupa authored Mar 10, 2024
2 parents e63d5e2 + 379b8be commit 96effd6
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3 changes: 1 addition & 2 deletions blog.html
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Expand Up @@ -12,8 +12,7 @@ <h2 class="h2-title">software engineering blog</h2>
<div class="nav-bar">
<ul>
<li><a class="a-look" href="index.html">home</a></li>
<li><a class="a-look" href="smart-contracts.html">smart contracts</a></li>
<li><a class="a-look" href="blog.html">blog</a></li>
<li><a class="a-look" href="dynamodb-with-go.html">DynamoDb with Golang</a></li>
</ul>
</div>
</div>
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246 changes: 246 additions & 0 deletions dynamodb-with-go.html
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<!DOCTYPE html>
<html>
<head>
<title>janzenbupa.github.io</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<div class="nav-bar-header">
<h2 class="h2-title">software engineering</h2>
<p></p>
</div>
<div class="nav-bar">
<ul>
<li><a class="a-look" href="index.html">home</a></li>
<li><a class="a-look" href="dynamodb-with-go.html">DynamoDb with Golang</a></li>
</ul>
</div>
</div>

<div class="p-center" style="padding-bottom: 20px;">
<H2 class="h2-title" style="color:#676798">Connecting to DynamoDb with Go</H2>
<p>After creating a Go project and initializing the module name, you can begin to import the necessary
packages required for connecting to DynamoDb.
</p>
<div style="text-align: center;">
<code class="codeblock" style="display: inline-block;text-align: left;width: 400px;margin-bottom: 20px;">
go get github.com/aws/aws-sdk-go/aws</br>
go get github.com/aws/aws-sdk-go/aws/credentials</br>
go get github.com/aws/aws-sdk-go/aws/session</br>
go get github.com/aws/aws-sdk-go/service/dynamodb</br>
</code>
</div>

<p>The next step after getting the required dependencies is to create the method that can connect to DynamoDb.</p>

<div class="code-container">
<code class="code-block">
sess := session.Must(session.NewSession(&aws.Config{
Region: aws.String("us-east-1"),
Credentials: credentials.NewStaticCredentials(
accessKey,
secretKey,
""),
}))

svc := dynamodb.New(sess)
return *svc
</code>
</div>

<p>This creates a connection to DynamoDb using https. This session is created and can be used to read and write to your database.</p>
<p>Now we are going to try writing to our data.</p>

<div class="code-container"style="height: 300px;margin-bottom: 20px;">
<code class="code-block" style="height: 300px;">
func Write(data SomeDataStruct) {
input := &dynamodb.PutItemInput{
TableName: aws.String("TableName"),
Item: map[string]*dynamodb.AttributeValue{
"Property/Column": {
S: aws.String(data.Property),
},
"DifferentProperty": {
S: aws.String(data.DifferentProperty),
},
},
}
_, err := svc.PutItem(input)
if err != nil {
return
}
}
</code>
</div>

<p>The code above will accept some data of type struct, for example, and map that data to properties in our database.</p>
<p>The &dynamodb.PutItemInput pointer allows us to define a variable named input of the PutItemInput struct type,
and allows us to set the Item field on that struct to our actual data that we need to save.</p>
<p>Item field would be an example of our data structure in DynamoDb.</p>

<p>Next, we may want to read the data that we have written to our database. The function below allows us to do that.</p>

<div class="code-container"style="height: 300px;margin-bottom: 20px;">
<code class="code-block" style="height: 300px;width: 550px;">
func Read(limit int64) ([]map[string]*dynamodb.AttributeValue, error) {
input := &dynamodb.ScanInput{
TableName: aws.String("TableName"),
Limit: aws.Int64(limit),
}

result, err := svc.Scan(input)
if err != nil {
return nil, err
}

items := result.Items

return items, nil
}
</code>
</div>

<p>Finally, we may just want to query a single item. To do that, all we have to do is create a pointer to a QueryInput struct, and define the attribute that we want to query on.</p>
<div class="code-container"style="height: 350px;margin-bottom: 20px;">
<code class="code-block" style="height: 320px;width: 700px;">
func ReadByAttribute(attrVal string) ([]map[string]*dynamodb.AttributeValue, error) {

input := &dynamodb.QueryInput{
TableName: aws.String("TableName"),
KeyConditionExpression: aws.String("AttributeVal = :attrVal"),
ExpressionAttributeValues: map[string]*dynamodb.AttributeValue{
":attrVal": {
S: aws.String(attrVal),
},
},
}

result, err := svc.Query(input)
if err != nil {
return nil, err
}

return result.Items, nil
}
</code>
</div>
<p>Our code accepts a parameter called attrVal, and queries our database based on a field named AttributeVal.</p>
<p>It will run a query that searches for the key AttributeVal, where the value of that key is equal to the value of attrVal that we passed in. It then returns every instance of that data.</p>
</div>
</body>
</html>

<style>
.p-center{
text-align: center;
}

.h2-title{
text-align: center;
color: #e6e6e6;
font-family: "Retina", Arial, Helvetica, sans-serif;
}

a{
font-family: "Retina", Arial, Helvetica, sans-serif;
}

a:link{
text-decoration: none;
color: Violet;
}

a:visited{
text-decoration: none;
color: Violet;
}

a:active{
text-decoration: none;
color: Violet;
}

.nav-bar-header{
background-color: #1f1f2e/*SlateBlue*/;
overflow: hidden;
margin: 0px;
border-bottom: 0.5px solid #676798/*LightSlateGray*/;
}

.nav-bar{
background-color: #676798;
overflow: hidden;
display: block;
padding: 0%;
text-decoration: none;
}

body{
margin: 0%;
}

.body-padding{
margin-left: 10%;
margin-right: 10%;
}


/*list heading nav bar*/
ul {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
background-color: #676798;
}

li {
float: left;
}

li a {
display: block;
color: Violet;
text-align: center;
padding: 14px 16px;
text-decoration: none;
}

li:active{
background-color: #1f1f2e;
}

li:hover{
background-color: #1f1f2e;
}

code {
background: hsl(0, 3%, 92%);
}

pre {
/* white-space: pre-wrap;
background: hsl(30,80%,90%); */
}

.code-container {
display: flex;
justify-content: center;
align-items: center;
height: 300px;
}

.code-block {
width: 500px;
height: 190px;
padding: 1px;
margin: 0px;
background-color: #f5f5f5;
border: 1px solid #ddd;
overflow: auto;
white-space: pre-wrap;
text-align: left;
}

</style>

6 changes: 3 additions & 3 deletions index.html
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Expand Up @@ -12,12 +12,12 @@ <h2 class="h2-title">Janzen is a software engineer</h2>
<div class="nav-bar">
<ul>
<li><a class="a-look" href="index.html">home</a></li>
<li><a class="a-look" href="smart-contracts.html">smart contracts</a></li>
<li><a class="a-look" href="blog.html">blog</a></li>
<li><a class="a-look" href="dynamodb-with-go.html">DynamoDb with Golang</a></li>
</ul>
</div>
<div class="body-padding">
<p class="p-center">He is passionate about learning new technologies and is currently focused on API development.</p>
<p class="p-center">I am passionate about learning new technologies and am currently focused on API development.</p>
<p class="p-center">Right now I am learning Golang and other technologies that can be used with alongside it.</p>
<div>

</body>
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123 changes: 0 additions & 123 deletions smart-contracts.html
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