Sathish Jayapal

We will go over a working example that uploads a photo to Azure Container as a Blob. The final codebase will run to upload a photo-based on a CURL command

curl -w "\n" http://localhost:7071/api/uploadSathishPhoto --data /Users/sathishjayapal/Downloads/DSCN4934.JPG

High level architecture

Prerequisites:

Azure CLI

Azure subscription

NPM

JAVA 8.

Maven CLI

Now let us see how to go about getting this to work with Azure functions. The reason I chose Azure functions is the free tier that you get for doing a quick app. The first million calls are free and there is a 5GB free space in the Azure storage. The API is front-ended with Azure API services. Few configurations can be done, but we will keep that in another post.
The first block we are going to look is the Function, to get this going, we will use the maven archetype for developing Azure functions.

mvn archetype:generate -DarchetypeGroupId=com.microsoft.azure -DarchetypeArtifactId=azure-functions-archetype

This creates a bare Azure function that can get an Http Post call to a URL. Two files will be created from the archetype. The first one is host.json and local.settings.json. Now the other important item to look is the pom.xml file.

 <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <azure.functions.maven.plugin.version>1.3.4</azure.functions.maven.plugin.version>   <azure.functions.java.library.version>1.3.0</azure.functions.java.library.version>
    <functionAppName>uploadSathishPhoto</functionAppName>
    <functionAppRegion>eastus</functionAppRegion>
    <stagingDirectory>${project.build.directory}/azure-functions/${functionAppName}
    </stagingDirectory>    <functionResourceGroup>photofunctionrg</functionResourceGroup>
  </properties>

The function name is uploadSathishPhoto
<functionAppName>uploadSathishPhoto</functionAppName>

We have to make sure the function name here matches with the Java Function API. So here is the JAVA API function

public class UploadSathishPhotoFunction {

  public static final String PHOTOPATH = "photopath";

  @FunctionName("uploadSathishPhoto")
  public HttpResponseMessage run(
      @HttpTrigger(name = "req", methods = {HttpMethod.GET,
          HttpMethod.POST}, authLevel = AuthorizationLevel.FUNCTION) HttpRequestMessage<Optional<String>> request,
      final ExecutionContext context) {
    context.getLogger ().info ("Java HTTP trigger processed a request.");

    String photometer;
    photometer = request.getQueryParameters ().get (PHOTOPATH);
    String photograph = request.getBody ().orElse (photometer);
    if (photograph == null) {
      return request.createResponseBuilder (HttpStatus.BAD_REQUEST)
          .body ("Please pass a photo path on the query string or in the request body").build ();
    } else {
    BlobServiceClient blobClient;
    BlobContainerClient container1;
    try {
      blobClient = BlobClientProvider.getBlobClientReference ();
      context.getLogger ().info ("\nCreate container ");
        container1 = createContainer (blobClient);
      context.getLogger ().info ("\n\tUpload a file as a block blob.");
      BlobClientProvider.uploadFileBlocksAsBlockBlob (container1, photograph);
      context.getLogger ().info ("\t\tSuccessfully uploaded the blob.");
    } catch (Throwable e) {
      context.getLogger ()
          .log (Level.SEVERE, "Java HTTP trigger processed a request.", e.fillInStackTrace ());
    }
      return request.createResponseBuilder (HttpStatus.OK).body ("Hello, " + photograph).build ();
    }
  }
}

Now the function relies on the Azure model, where there is a Need for a BlobClient to start the entire upload function. Then there is a container that holds on the blob. Finally, the blob item will be stored. In our application, we have two classes that are going to take care of the initializing a BlobClient and Container. We are going to upload all the pictures in this function to a specific container. The source code for these classes is checked into.

To run the function run the maven commands

mvn clean install
mvn azure-functions:run

When doing the install, keep an eye on When doing the install, keep an eye on the console output to make sure there is an Azure function being built. This gives an indication to us that the function is being packaged.

[INFO] Step 1 of 7: Searching for Azure Functions entry points
[INFO] 1 Azure Functions entry point(s) found.

In order to run the application locally, the maven command is

 mvn azure-functions:run

Keep an eye on the console to make sure the function is started


uploadSathishPhoto: [GET,POST] http://localhost:7071/api/uploadSathishPhoto

Hosting environment: Production
Content root path: /Users/sathishjayapal/IdeaProjects/blob-azfunction-start/target/azure-functions/uploadSathishPhoto
Now listening on: http://0.0.0.0:7071
Application started. Press Ctrl+C to shut down.
[01/13/2020 02:47:54] Host lock lease acquired by instance ID '0000000000000000000000004DD021D9'.

To check if all works, CURL command is

curl -w "\n" http://localhost:7071/api/uploadSathishPhoto --data /Users/sathishjayapal/Downloads/DSCN4934.JPG

The JPG will get uploaded based on the param that is being passed to the CURL. To confirm let us look at the Azure portal.

The complete code for this can be found here. As well Azure has a great getting started guides. Check these following links

https://github.com/Azure-Samples

This entire post is based on JAVA 8 version. I got some specific errors when running in versions other than JAVA 8.

We have a simple cloud formation file in a YAML format. There are couple of parameters that need to be passed to this template. We want to make sure the parameters that are being passed are based on whether it is a PROD/Test environment.

Here is the sample simple S3 upload file template

AWSTemplateFormatVersion: 2010-09-09
Metadata:
  ...
Parameters:
  S3BucketName:
    ...
    Type: String
  CorsIDRuleName:
    Default: DEVCorsRuleID
    Description: Cors ID Rule information for the s3 bucket to post
    Type: String      
Resources:
  S3B3SR4G:
    Type: 'AWS::S3::Bucket'
    Properties:
      BucketName: !Ref S3BucketName
      AccessControl: PublicRead
      CorsConfiguration:
        CorsRules:
        ...
         	Id: !Ref CorsIDRuleName
          MaxAge: '3600'

Now based on the environment, we have two parameter files that have to be used. For test we will use the test-config.json file and production we will use the prod-config.json file.

Sample test-config.json

[
{
"ParameterKey": "S3BucketName",
"ParameterValue": "mynewawesomebucket20191231"
},
{
"ParameterKey": "CorsIDRuleName",
"ParameterValue": "myawesomecorsruleid"
}
]

To run the stack from cloud formation we can run the command

aws cloudformation create-stack --stack-name startmyinstance  --template-body file://template1.yaml --parameters file:///S3Uploader/test-stack-s3-configuration.json

Few take aways:

I was not able to pass parameters from another yaml file
Template can be yaml, but when parameters are to be externalized then it is had to be from a JSON file only
Parameter file though in JSON had to follow some specific conventions for yaml file. In our example “ParameterKey”, “ParameterValue” had to be in the format for CF/YAML config. To pick up.
Sample code for this is at github

Author: Sathish Jayapal

Cloud opinion summary 2020.

Black History Moments in Search – Google

Azure functions Photo upload function using JAVA

High level architecture

Prerequisites:

Cloudformation YAML file pass parameters

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