Skip to main content

List Databases

Retrieves a list of all databases available on the MongoDB server along with their metadata.

Common Properties​

  • Name - The custom name of the node.
  • Color - The custom color of the node.
  • Delay Before (sec) - Waits in seconds before executing the node.
  • Delay After (sec) - Waits in seconds after executing node.
  • Continue On Error - Automation will continue regardless of any error. The default value is false.
info

If the ContinueOnError property is true, no error is caught when the project is executed, even if a Catch node is used.

Inputs​

  • MongoDB Client Id - The client ID returned from the Connect node (optional if credentials are provided).

Options​

  • Credentials - Database credentials (Category 5) - optional if using Client ID from Connect node. This allows you to perform the operation without a separate Connect node.

Output​

  • DB List - An object containing information about all databases on the server, including:
    • databases - Array of database objects, each containing:
      • name - The name of the database
      • sizeOnDisk - Size of the database in bytes
      • empty - Boolean indicating if the database is empty
    • totalSize - Total size of all databases in bytes
    • totalSizeMb - Total size in megabytes (if applicable)
    • ok - Status indicator (1 for success)

How It Works​

The List Databases node queries the MongoDB server for database information. When executed, the node:

  1. Obtains a MongoDB client (either from client ID or by creating one from credentials)
  2. Calls the ListDatabases command with an empty filter
  3. Retrieves metadata about all databases the user has access to
  4. Returns the complete database list with size and status information
  5. Stores the result in the specified output variable

Requirements​

  • Either a valid client ID from Connect node OR database credentials
  • Appropriate permissions to list databases on the MongoDB server
  • The user must have the listDatabases privilege

Error Handling​

The node will return specific errors in the following cases:

  • ErrInvalidArg - Client ID or credentials are invalid
  • ErrConnection - Cannot connect to MongoDB (when using credentials)
  • Permission errors if the user doesn't have database listing rights

Usage Notes​

  • System databases (admin, local, config) are included in the list
  • The size information reflects the current disk usage
  • Empty databases (with no data) may still show a small size due to metadata
  • You can use either the client ID approach or direct credentials approach
  • The output is useful for monitoring, reporting, and automation decisions
  • Database names are returned as they exist on the server (case-sensitive)

Output Format Example​

{
  "databases": [
    {
      "name": "admin",
      "sizeOnDisk": 40960,
      "empty": false
    },
    {
      "name": "sales_data",
      "sizeOnDisk": 2097152,
      "empty": false
    },
    {
      "name": "test",
      "sizeOnDisk": 0,
      "empty": true
    }
  ],
  "totalSize": 2138112,
  "ok": 1
}

Example Usage​

Scenario 1: List all databases using Connect node

  1. Connect node → Client Id
  2. List Databases:
    • MongoDB Client Id: (from Connect)
    • Output: db_list
  3. Log: {{db_list}}

Scenario 2: List databases using direct credentials

  1. List Databases:
    • MongoDB Client Id: (leave empty)
    • Credentials: (select database credential)
    • Output: databases
  2. Process the database list

Scenario 3: Find databases by pattern

List Databases → db_list

For Each database in db_list.databases:
  If database.name starts with "prod_":
    Log: "Production database found: " + database.name
    Log: "Size: " + database.sizeOnDisk + " bytes"

Scenario 4: Monitor database sizes

List Databases → db_list

Set Variable:
  - total_mb = db_list.totalSize / (1024 * 1024)

If total_mb > 10000:
  Send Alert: "Total database size exceeds 10GB: " + total_mb + "MB"

Common Use Cases​

  • Monitoring: Track database sizes and growth over time
  • Inventory: Get a complete list of all databases on the server
  • Validation: Verify that required databases exist
  • Cleanup: Identify empty or obsolete databases for removal
  • Reporting: Generate database usage reports
  • Automation: Make decisions based on database existence or size
  • Auditing: Log all databases for compliance purposes

Common Errors​

Permission Denied:

  • Cause: User doesn't have permission to list databases
  • Solution: Ensure the user has the listDatabases action privilege

Invalid Client:

  • Cause: Client ID doesn't exist or connection is closed
  • Solution: Verify the Connect node executed successfully and the client ID is valid

Processing the Output​

Access all database names:

db_list.databases.map(db => db.name)

Find a specific database:

db_list.databases.find(db => db.name === "mydb")

Calculate total size in MB:

db_list.totalSize / (1024 * 1024)

Filter non-empty databases:

db_list.databases.filter(db => !db.empty)
  • Create Database - Create a new database
  • Drop Database - Delete a database
  • Show Collections - List collections within a specific database