Pruning Lambda Versions

Lambda version pruning is built into the Serverless Framework. Thanks to Clay Gregory and contributors for the original serverless-prune-plugin.

Why Prune?

AWS Lambda retains all published versions of your functions. Over time, this can:

• Consume storage quota
• Clutter the Lambda console
• Slow down deployment tooling that enumerates versions (due to pagination / extra API calls)

The prune feature automatically removes old versions while keeping a configurable number of recent versions.

Configuration

Add the prune section to your custom block:

custom:
  prune:
    automatic: true # Prune after each deploy
    number: 3 # Keep 3 most recent versions
    includeLayers: true # Also prune layer versions

Configuration Options

Manual Pruning

Use the prune command to manually clean up versions:

# Keep 5 most recent versions
serverless prune -n 5

# Preview what would be deleted
serverless prune -n 3 --dryRun --verbose

# Prune a specific function
serverless prune -n 3 -f myFunction

# Prune layers only
serverless prune -n 3 -l myLayer

# Prune functions and layers
serverless prune -n 3 --includeLayers

Alias Protection

Versions that are referenced by Lambda aliases will never be deleted, regardless of the number setting. This ensures stable deployments and traffic shifting configurations remain intact.

Dry Run Mode

Use --dryRun with --verbose to preview what would be deleted:

serverless prune -n 3 --dryRun --verbose

Output:

Prune: myFunction:4 selected for deletion.
Prune: myFunction:3 selected for deletion.
Prune: Dry-run enabled, no pruning actions will be performed.