datamog

datamog-gsheet

Google Sheets loader plugin for Datamog. Populates extensional predicate tables from Google Sheets using the google-spreadsheet library.

Quick start

Given a Datamog program that declares an extensional predicate:

extensional parent(name: string, child: string).

Point it at a Google Sheet with --extensional:

# Public sheet (API key)
GOOGLE_API_KEY=... bun run datamog --extensional parent=https://docs.google.com/spreadsheets/d/SPREADSHEET_ID program.dl

# Private sheet (service account)
GOOGLE_SERVICE_ACCOUNT_EMAIL=... GOOGLE_PRIVATE_KEY=... bun run datamog --extensional parent=https://docs.google.com/spreadsheets/d/SPREADSHEET_ID program.dl

The first row of the sheet must contain headers that match the declared column names (e.g. name, child).

Authentication

Two methods are supported. If both are set, service account takes precedence.

API key (public sheets)

For spreadsheets shared as “Anyone with the link can view”.

1. Create a Google Cloud project and enable the Google Sheets API.
2. Create an API key under APIs & Services > Credentials.
3. Set the GOOGLE_API_KEY environment variable.

export GOOGLE_API_KEY=AIza...

Service account (private sheets)

For spreadsheets that are not publicly shared. This is the recommended approach for production use.

1. Create a Google Cloud project and enable the Google Sheets API.
2. Create a service account under IAM & Admin > Service Accounts.
3. Generate a JSON key for the service account and note the client_email and private_key fields.
4. Share the spreadsheet with the service account’s email address (as Viewer or Editor).
5. Set the environment variables:

export GOOGLE_SERVICE_ACCOUNT_EMAIL=my-service@my-project.iam.gserviceaccount.com
export GOOGLE_PRIVATE_KEY="-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n"

Configuration

Each predicate is mapped to a spreadsheet via the sheets option:

{
  spreadsheetId: "...",  // Google Sheets spreadsheet ID (required)
  range: "Sheet1",       // Sheet/tab name (default: "Sheet1")
}

When using the CLI with --extensional, the spreadsheet ID is extracted from the Google Sheets URL automatically. To select a specific tab, there is currently no CLI flag — the default tab Sheet1 is used.

Programmatic API

import { DatamogExecutor } from "datamog-engine";
import { GSheetLoader } from "datamog-gsheet";

const loader = new GSheetLoader({
  auth: { apiKey: process.env.GOOGLE_API_KEY! },
  // or: auth: { serviceAccountEmail: "...", privateKey: "..." },
  sheets: {
    parent: { spreadsheetId: "1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgVE2upms" },
    edge: { spreadsheetId: "1abc...", range: "Edges" },
  },
});

const executor = new DatamogExecutor(backend, [loader]);

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