Delete items from a datastore

There are a couple ways you can delete items from a datastore. You can:

• Delete items with delete and bulkDelete
• Delete items automatically

Delete items with delete and bulkDelete

There are two methods for deleting items in datastores:

• The apps.datastore.delete method is used for single items.
• The apps.datastore.bulkDelete method is used for multiple items.

They work quite similarly. In the following examples we'll be deleting items from a datastore via their primary key. Regardless of what you named your primary_key, the query will always use the id key.

// Somewhere in your function:
const uuid = "6db46604-7910-4684-b706-ac5929dd16ef";
const response = await client.apps.datastore.delete({
  datastore: "drafts",
  id: uuid,
});

if (!response.ok) {
  const error = `Failed to delete a row in datastore: ${response.error}`;
  return { error };
}

// Somewhere in your function:
const uuid = "6db46604-7910-4684-b706-ac5929dd16ef";
const uuid2 = "1111111-1111-1111-1111-111111111111";
const response = await client.apps.datastore.bulkDelete({
  datastore: "drafts",
  ids: [uuid,uuid2]
});

if (!response.ok) {
  const error = `Failed to delete a row in datastore: ${response.error}`;
  return { error };
}

If the call was successful, the payload's ok property will be true. If it is not successful, it will be false and provide an error in the errors property.

Delete items automatically

You can set up your datastore to automatically delete records which are old and no longer relevant. This is done with the Time To Live (TTL) feature offered by AWS DynamoDB. Use it to efficiently discard data your app no longer needs.

For any item, define an expiration timestamp and the item will be automatically deleted once that expiration time has passed.

Notice that we didn't say immediately deleted. AWS only guarantees deletion of expired items 48 hours past the expiration date. If you query your table before 48 hours have passed, do not assume all expired items have been deleted. You can read more about this within the AWS documentation.

See below for an example on querying a database while filtering out any remaining expired items.

Enable and utilize the TTL feature

Step 1. Select an attribute to use as the expiration timestamp

You can use a pre-existing attribute or add a new attribute.

The attribute's type must be set as Schema.slack.types.timestamp in the datastore definition.

In this example, we're using an attribute called expire_ts:

// /datastores/drafts.ts
import { DefineDatastore, Schema } from "deno-slack-sdk/mod.ts";

export default DefineDatastore({
  name: "drafts",
  primary_key: "id",
  attributes: {
    id: {
      type: Schema.types.string,
    },
    expire_ts: {
      type: Schema.slack.types.timestamp // This line!
    }
  },
  ...
});

Step 2. Set time_to_live_attribute to the selected attribute in the datastore definition

// /datastores/drafts.ts
import { DefineDatastore, Schema } from "deno-slack-sdk/mod.ts";

export default DefineDatastore({
  name: "drafts",
  time_to_live_attribute: "expire_ts" // This line!
  primary_key: "id",
  attributes: {
    id: {
      type: Schema.types.string,
    },
    expire_ts: {
      type: Schema.slack.types.timestamp
    },
    message: {
      type: Schema.types.string,
    }
  },
  ...
});

Step 3. Set expire_ts to a value, either programmatically or manually

In this example we're adding an item containing the expire_ts key using the apps.datastore.put method:

    const expiration = 
    const putResp = await client.apps.datastore.put<
      typeof DraftDatastore.definition
    >({
      datastore: DraftDatastore.name,
      item: {
        id: draftId,
        expire_ts: 23456432345,
        message: "Congrats on the promotion Jesse!"
      },
    });

Step 4. Deploy your app

Use the slack deploy command. See Deploy to Slack for more information.

Step 5. Properly query items

As mentioned above, expired items may not be deleted immediately. You'll likely want to filter out those expired items.

Here is an example of a query that filters out any expired items that have not been automatically deleted yet:

const result = await client.apps.datastore.query({
    datastore: "DraftDatastore", 
    expression: "attribute_not_exists(#expire_ts) OR #expire_ts > :timestamp", 
    expression_attributes: { "#expire_ts": "expire_ts" }, 
    expression_values: { ":timestamp":1708448410 } //Timestamp should be the current time
});

To see an example of filtering out expired items via the command line, see the documentation on the datastore query command.

Disable the TTL feature

Step 1. Remove time_to_live_attribute in the datastore definition

We only commented it out here because showing the absence of something is a bit anticlimactic.

export default DefineDatastore({
  name: "drafts",
  primary_key: "id",
  attributes: {
    id: {
      type: Schema.types.string,
    },
    //expire_ts: {
    //  type: Schema.slack.types.timestamp
    //}
  },
  ...
});

Step 2. Deploy your app.

Use the slack deploy command. See Deploy to Slack for more information.

Change the TTL attribute

Due to AWS limitations, changing the TTL attribute is a bit clunky.

Step 1. Disable TTL

Step 2. Wait one hour. This wait is because AWS puts time limits on additional changes to the TTL feature.

Step 3. Enable TTL again with the new attribute

Don't forget to deploy both when disabling and enabling TTL!