# Source: https://docs.unstructured.io/examplecode/tools/gcs-events.md

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.unstructured.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Google Cloud Storage event triggers

You can use Google Cloud Storage events, such as adding new files to—or updating existing files within—Google Cloud Storage buckets, to automatically run Unstructured ETL+ workflows
that rely on those buckets as sources. This enables a no-touch approach to having Unstructured automatically process new and updated files in Google Cloud Storage as they are added or updated.

This example shows how to automate this process by adding a custom [Google Apps Script](https://developers.google.com/apps-script) project in your Google account. This project runs
a script on a regular time interval. This script automatically checks for new or updated files within the specified Google Cloud Storage bucket. If the script
detects at least one new or updated file, it then calls the [Unstructured API's workflow operations](/api-reference/workflow/overview) to automatically run the
specified corresponding Unstructured ETL+ workflow in your Unstructured account.

<Note>
  This example uses a custom Google Apps Script that you create and maintain.
  Any issues with file detection, timing, or script execution could be related to your custom script,
  rather than with Unstructured. If you are getting unexpected or no results, be sure to check your custom
  script's execution logs first for any informational and error messages.
</Note>

## Requirements

To use this example, you will need the following:

* An Unstructured account, and an Unstructured API key for your account, as follows:

  1. If you do not already have an Unstructured account, [sign up for free](https://unstructured.io/?modal=try-for-free).
     After you sign up, you are automatically signed in to your new Unstructured **Let's Go** account, at [https://platform.unstructured.io](https://platform.unstructured.io).

     <Note>
       To sign up for a **Business** account instead, [contact Unstructured Sales](https://unstructured.io/?modal=contact-sales), or [learn more](/api-reference/overview#pricing).
     </Note>

  2. If you have an Unstructured **Let's Go**, **Pay-As-You-Go**, or **Business SaaS** account and are not already signed in, sign in to your account at [https://platform.unstructured.io](https://platform.unstructured.io).

     <Note>
       For other types of **Business** accounts, see your Unstructured account administrator for sign-in instructions,
       or email Unstructured Support at [support@unstructured.io](mailto:support@unstructured.io).
     </Note>

  3. Get your Unstructured API key:<br />

     a. After you sign in to your Unstructured **Let's Go**, **Pay-As-You-Go**, or **Business** account, click **API Keys** on the sidebar.<br />

     <Note>
       For a **Business** account, before you click **API Keys**, make sure you have selected the organizational workspace you want to create an API key
       for. Each API key works with one and only one organizational workspace. [Learn more](/ui/account/workspaces#create-an-api-key-for-a-workspace).
     </Note>

     b. Click **Generate API Key**.<br />
     c. Follow the on-screen instructions to finish generating the key.<br />
     d. Click the **Copy** icon next to your new key to add the key to your system's clipboard. If you lose this key, simply return and click the **Copy** icon again.<br />

* The Unstructured API's workflow operations URL for your account, as follows:

  1. In the Unstructured UI, click **API Keys** on the sidebar.<br />
  2. Note the value of the **Unstructured API's workflow operations** field.

* A Google Cloud Storage source connector in your Unstructured account. [Learn how](/ui/sources/google-cloud).

* Some available [destination connector](/ui/destinations/overview) in your Unstructured account.

* A workflow that uses the preceding source and destination connectors. [Learn how](/ui/workflows).

* An OAuth 2.0 client ID and client secret to call the Google API, as follows:

  1. Sign in to your [Google Cloud account](https://cloud.google.com).
  2. Go to the [Google Cloud APIs dashboard](https://console.cloud.google.com/apis/dashboard).
  3. Click **+ Enable APIs and services**.
  4. In the **Search for APIs & Services** box, enter `Cloud Storage API`.
  5. In the list of search results, click **Cloud Storage API**.
  6. Make sure that **API Enabled** is shown. If not, click **Enable**.
  7. Go to your [Google Cloud console welcome page](https://console.cloud.google.com/welcome).
  8. In the **Search (/) for resources, docs, products, and more** box, enter `Credentials`.
  9. Click **Credentials (APIs & Services)**.
  10. Click **+ Create credentials > OAuth client ID**.
  11. For **Application type**, select **Web application**.
  12. (Optional) Enter some non-default **Name** for this OAuth 2.0 client to be shown in the list of created clients in your Google Cloud Console.
  13. Click **Create**.
  14. After the OAuth client is created, click **Download JSON** to save the client ID and client secret values to a JSON file on your local
      machine. Store this JSON file in a secure location.

## Step 1: Create the Google Apps Script project

1. Go to [http://script.google.com/](http://script.google.com/).
2. Click **+ New project**.
3. Click the new project's default name (such as **Untitled project**), and change it to something more descriptive, such as **Unstructured Scripts for GCS**.

## Step 2: Add the script

1. With the project still open, on the sidebar, click the **\< >** (**Editor**) icon.

2. In the **Files** tab, click **Code.gs**.

3. Replace the contents of the `Code.gs` file with the following code instead:

   ```javascript  theme={null}
   // Configure the OAuth2 service.
   function getOAuthService() {
     return OAuth2.createService('GCS')
       .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/auth')
       .setTokenUrl('https://oauth2.googleapis.com/token')
       .setClientId(CLIENT_ID)
       .setClientSecret(CLIENT_SECRET)
       .setCallbackFunction('authCallback')
       .setPropertyStore(PropertiesService.getUserProperties())
       .setScope(OAUTH_SCOPE);
   }

   // OAuth2 callback function.
   function authCallback(request) {
     const service = getOAuthService();
     const isAuthorized = service.handleCallback(request);
     return HtmlService.createHtmlOutput(isAuthorized ? 'Success!' : 'Denied');
   }

   // Get a valid access token (refreshes automatically if expired).
   function getAccessToken() {
     const service = getOAuthService();
     if (!service.hasAccess()) {
       const authorizationUrl = service.getAuthorizationUrl();
       Logger.log('Open the following URL and re-run the script: %s', authorizationUrl);
       throw new Error('Authorization required. Open the URL in the log.');
     }
     return service.getAccessToken();
   }

   // Main function: checks for new or updated files in the bucket.
   function checkForNewOrUpdatedGCSFiles() {
     const thresholdMillis = 5 * 60 * 1000; // 5 minutes.
     const now = new Date();

     // Get (and refresh if needed) the access token.
     const accessToken = getAccessToken();

     // List objects in the bucket.
     const apiUrl = `https://storage.googleapis.com/storage/v1/b/${BUCKET_PATH}/o`;
     const response = UrlFetchApp.fetch(apiUrl, {
       method: 'get',
       headers: {
         'Authorization': 'Bearer ' + accessToken,
         'Accept': 'application/json'
       }
     });
     const data = JSON.parse(response.getContentText());
     const files = data.items || [];

     for (let i = 0; i < files.length; i++) {
       const file = files[i];
       const fileName = file.name;
       const created = new Date(file.timeCreated);
       const updated = new Date(file.updated);

       const millisSinceCreated = now - created;
       const createdWithinThreshold = millisSinceCreated < thresholdMillis;
       const millisSinceUpdated = now - updated;
       const updatedWithinThreshold = millisSinceUpdated < thresholdMillis;

       console.log('File Name:                       ' + fileName);
       console.log('Created:                         ' + created);
       console.log('Last updated:                    ' + updated);
       console.log('Milliseconds since created:      ' + millisSinceCreated);
       console.log('Milliseconds since last updated: ' + millisSinceUpdated);
       console.log('Created within threshold of ' + thresholdMillis + ' milliseconds? ' + createdWithinThreshold);
       console.log('Updated within threshold of ' + thresholdMillis + ' milliseconds? ' + updatedWithinThreshold);
       console.log('-----');

       if (createdWithinThreshold || updatedWithinThreshold) {
         // Trigger your workflow.
         UrlFetchApp.fetch(UNSTRUCTURED_API_URL, {
           method: 'post',
           headers: {
             'accept': 'application/json',
             'unstructured-api-key': UNSTRUCTURED_API_KEY
           }
         });
         console.log('At least one file created or updated within threshold of ' + thresholdMillis + ' milliseconds.');
         console.log('Unstructured workflow request sent to ' + UNSTRUCTURED_API_URL);
         return;
       }
     }
     console.log('No files created or updated within threshold of ' + thresholdMillis + ' milliseconds. No Unstructured workflow request sent.');
   }

   ```

4. Click the **Save project to Drive** button.

## Step 3: Customize the script for your workflow

1. With the project still open, on the **Files** tab, click the **Add a file** button, and then click **Script**.

2. Name the new file `Constants`. The `.gs` extension is added automatically.

3. Replace the contents of the `Constants.gs` file with the following code instead:

   ```javascript  theme={null}
   const BUCKET_PATH = '<bucket-path>';
   const UNSTRUCTURED_API_URL = '<unstructured-api-url>' + '/workflows/<workflow-id>/run';
   const UNSTRUCTURED_API_KEY = '<unstructured-api-key>';
   const CLIENT_ID = '<client-id>';
   const CLIENT_SECRET = '<client-secret>';
   const OAUTH_SCOPE = 'https://www.googleapis.com/auth/devstorage.read_only'; // Or .read_write or .full_control
   ```

   Replace the following placeholders:

   * Replace `<bucket-path>` with the path to your Google Cloud Storage bucket. This is the same path that you specified
     when you created your Google Cloud Storage source connector in your Unstructured account. Do not include the `gs://` prefix here.
   * Replace `<unstructured-api-url>` with your Unstructured API URL value.
   * Replace `<workflow-id>` with the ID of your Unstructured workflow.
   * Replace `<unstructured-api-key>` with your Unstructured API key value.
   * Replace `<client-id>` with your OAuth 2.0 client ID value.
   * Replace `<client-secret>` with your OAuth 2.0 client secret value.

4. Click the disk (**Save project to Drive**) icon.

## Step 4: Generate an initial OAuth 2.0 access token

1. On the sidebar, click the gear (**Project Settings**) icon.
2. In the **IDs** area, next to **Script ID**, click **Copy** to copy the script's ID value to your system's clipboard.
3. In a separate tab in your web browser, open your [Google Cloud Console welcome page](https://console.cloud.google.com/welcome).
4. In the **Search (/) for resources, docs, products, and more** box, enter `Credentials`.
5. Click **Credentials (APIs & Services)**.
6. In the **OAuth 2.0 client IDs** list, click the link for the client ID that you created earlier in the requirements.
7. Under **Authorized redirect URIs**, click **Add URI**.
8. In the **URIs 1** box, enter `https://script.google.com/macros/d/<script-id>/usercallback`, replacing `<script-id>` with the script's ID value that you copied earlier.
9. Click **Save**.
10. On the original tab in your web browser, with the Google Apps Script project still open to the **Constants.gs** file, on the sidebar, next to **Libraries**, click the **+** (**Add a library**) icon.
11. For **Script ID**, enter `1B7FSrk5Zi6L1rSxxTDgDEUsPzlukDsi4KGuTMorsTQHhGBzBkMun4iDF`, and then click **Look up**.
12. For **Version**, make sure the largest number is selected.
13. Click **Add**.
14. In the sidebar, click the **Code.gs** file to open it.
15. In the file's top navigation bar, select **getAccessToken**.
16. Click the **Run** icon.
17. In the **Execution log** area, next to the message `Open the following URL and re-run the script`, copy the entire URL into
    a separate tab in your web browser and then browse to that URL.
18. When prompted, click **Review permissions**, and follow the on-screen instructions to grant the necessary permissions.

## Step 5: Create the script trigger

1. On the original tab in your web browser, with the Google Apps Script project still open, on the sidebar, click the alarm clock (**Triggers**) icon.

2. Click the **+ Add Trigger** button.

3. Set the following values:

   * For **Choose which function to run**, select `checkForNewOrUpdatedGCSFiles`.

   * For **Choose which deployment should run**, select **Head**.

   * For **Select event source**, select **Time-driven**.

   * For **Select type of time based trigger**, select **Minutes timer**.

   * For **Select minute interval**, select **Every 5 minutes**.

     <Note>
       If you change **Minutes timer** or **Every 5 minutes** to a different interval, you should also go back and change the number `5` in the following
       line of code in the `checkForNewOrUpdatedFiles` function. Change the number `5` to the number of minutes that correspond to the alternate interval you
       selected:

       ```javascript  theme={null}
       const thresholdMillis = 5 * 60 * 1000;
       ```
     </Note>

   * For **Failure notification settings**, select an interval such as immediately, hourly, or daily.

4. Click **Save**.

## Step 6: View trigger results

1. With the Google Apps Script project still open, on the sidebar, click the three lines (**Executions**) icon.

2. As soon as the first script execution completes, you should see a corresponding message appear in the **Executions** list. If the **Status** column shows
   **Completed**, then keep going with this procedure.

   If the **Status** column shows **Failed**, expand the message to
   get any details about the failure. Fix the failure, and then wait for the next script execution to complete.

3. When the **Status** column shows **Completed** then, in your Unstructured account's user interface, click **Jobs** on the sidebar to see if a new job
   is running for that worklow.

   If no new job is running for that workflow, then add at least one new file to—or update at least one existing file within—the Google Cloud Storage bucket,
   within 5 minutes of the next script execution. After the next script execution, check the **Jobs** list again.

## Step 7 (Optional): Delete the trigger

1. To stop the script from automatically executing on a regular basis, with the Google Apps Script project still open, on the sidebar, click the alarm clock (**Triggers**) icon.
2. Rest your mouse pointer on the trigger you created in Step 5.
3. Click the ellipsis (three dots) icon, and then click **Delete trigger**.