Automatic encoding implementation using Cloud Functions

Available in Classic and VPC

VOD Station encodes using the connection with Object Storage bucket, however, it does not provide the feature to automatically encode by checking if the file was uploaded to the bucket. However, you can implement a similar function utilizing the event management feature and Cloud Functions.

Automatic encoding flow

The order of implementing automatic encoding is as follows.

1. Upload media files to Object Storage
2. Trigger uploaded event from Object Storage
3. Request encoding API for VOD Station through Cloud Functions
4. Perform encoding at VOD Station

Implementation Guide

An example of implementing automatic encoding using Object Storage, Cloud Functions, and VOD Station API is as follows.

1. Set an event to the bucket to store the original file of Object Storage
   1. Click the Event management menu of the bucket you wish to set an event at Object Storage > Bucket Management
   2. Event management pop-up > click the create button
   3. Create a bucket event
      • Enter event name
      • Filter settings: enter the condition to be used when filtering events for a specific object
        • Enter the condition as a regular expression. (<example> prefix images/: ^images/)
        • The filter applies to the object path. Events occur for all objects if no filter is entered.
      • Event type: unit creation (PUT)
        • Upon a new file upload, both POST and PUT events occur at the same time. Therefore, if you select both POST and PUT, the encoding action trigger may occur twice.
        • Overwriting can only happen for PUT events.
      • Target: cloud Functions
        • If you do not have a trigger created before, click the Create trigger button to create a trigger.
          • In the Create Trigger pop-up, enter only the name and click the create button.
          • You must set the action to connect to the trigger (logic to perform), however, if you haven't made one already, skip it.
        • Select the created trigger
          • You do not require a connected action at this stage.
        • Read the recursive call caution and mark it checked.
2. Action setting in Cloud Functions
   1. Click the Cloud Functions > Action > Create action button
   2. Set the trigger condition on the Create Action page
      • Trigger type: select Object Storage.
      • Name: select the trigger you created in the previous stage and click the add button.
      • Read the recursive call caution and mark it checked.
   3. Set the logic for the Action
      • Package: select a package (group) you want. If there is none, create a new one.
      • Type: basic (can select sequence if needed)
      • Name: enter a name for the action you’re creating.
      • Source code: the customer must implement the business logic for the creating action themselves. Please see the example source code at the bottom of this guide.
      • VPC connection information: if the selected platform is a VPC environment, select a VPC and subnet to connect to. If not, create a new one.

Automatic encoding action source code setting

An example Cloud Functions settings is as follows.

• Example parameter

  • Default Parameter (JSON Object)

    • Set as below.

    {
        "base_url": "https://vodstation.apigw.ntruss.com",
        "api_url": "/api/v2/category/{CATEGORY-ID}/add-files",
        "access_key": "{API-ACCESS-KEY}",
        "secret_key": "{API-SECRET-KEY}"
    }
    

    • {CATEGORY-ID}: substitute with the category ID for the encoding.
    • {API-ACCESS-KEY}: substitute with the user's Access Key.
    • {API-SECRET-KEY}: substitute with the user's Secret Key.

• Example source code

  • The example was implemented on Python 3.7 and it can be implemented in a different language.

  import hashlib
  import hmac
  import base64
  import requests
  import time
  import json
  
  
  def make_signature(url, timestamp, access_key, secret_key):
      timestamp = int(time.time() * 1000)
      timestamp = str(timestamp)
  
      secret_key = bytes(secret_key, "UTF-8")
  
      method = "PUT"
  
      message = method + " " + url + "\n" + timestamp + "\n" + access_key
      message = bytes(message, "UTF-8")
      sign_key = base64.b64encode(
          hmac.new(secret_key, message, digestmod=hashlib.sha256).digest()
      )
      print(sign_key)
      return sign_key
  
  
  def make_header(timestamp, access_key, sign_key):
      headers = {
          "Content-Type": "application/json; charset=utf-8",
          "x-ncp-apigw-timestamp": timestamp,
          "x-ncp-iam-access-key": access_key,
          "x-ncp-apigw-signature-v2": sign_key,
      }
      return headers
  
  
  def main(args):
      object_name = args.get("object_name")
      input_bucket_name = args.get("container_name")
  
      api_url = args["api_url"]
      full_url = f'{args["base_url"]}{api_url}'
      timestamp = str(int(time.time() * 1000))
  
      sign_key = make_signature(
          api_url, timestamp, args["access_key"], args["secret_key"]
      )
      headers = make_header(timestamp, args["access_key"], sign_key)
  
      try:
          res = requests.put(full_url, headers=headers, data=json.dumps({'bucketName' : input_bucket_name, 'pathList': [ object_name ] }))
  
          if res.status_code == 200:
              return {"input_bucket": input_bucket_name, "object_path": object_name, "res": res.text, "done": True}
          else:
              raise Exception({"done": False, "error_message": res.text})
  
      except Exception as e:
          raise Exception({"done": False, "error_message": str(e)})