full snapstart and provisioned concurrency support

README.md

@@ -1180,6 +1180,7 @@ to change Zappa's behavior. Use these at your own risk!
         // If you are adding a Function URL manually (e.g. outside Zappa) and seeing 403s with NONE
         // auth, this two-statement shape is the missing piece.
         "apigateway_version": "v1", // optional, API Gateway version to use. Can be "v1" or "v2". Default "v1".
+        "apigateway_lambda_qualifier": "live", // optional, Lambda version or alias for API Gateway integrations. Default null uses the unqualified function ARN, except when `snap_start` or `provisioned_concurrency` is enabled, in which case it defaults to Zappa's managed alias for that feature (see `snap_start`/`provisioned_concurrency` below). Set this only to point at your own alias instead.
         "architecture": "x86_64", // optional, Set Lambda Architecture, defaults to x86_64. For Graviton 2 use: arm64
         "async_source": "sns", // Source of async tasks. Defaults to "lambda"
         "async_resources": true, // Create the SNS topic and DynamoDB table to use. Defaults to true.
@@ -1263,27 +1264,28 @@ to change Zappa's behavior. Use these at your own risk!
         "lambda_description": "Your Description", // However you want to describe your project for the AWS console. Default "Zappa Deployment".
         "lambda_handler": "your_custom_handler", // The name of Lambda handler. Default: handler.lambda_handler
         "layers": ["arn:aws:lambda:<region>:<account_id>:layer:<layer_name>:<layer_version>"], // optional lambda layers
-        "lambda_concurrency": 10, // Sets the maximum number of simultaneous executions for a function, and reserves capacity for that concurrency level. Default is None.
+        "lambda_concurrency": 10, // Sets the maximum number of simultaneous executions for a function, and reserves capacity for that concurrency level. Default is None. If `provisioned_concurrency` is also set, it cannot exceed this value.
         "lets_encrypt_key": "s3://your-bucket/account.key", // Let's Encrypt account key path. Can either be an S3 path or a local file path.
         "log_level": "DEBUG", // Set the Zappa log level. Can be one of CRITICAL, ERROR, WARNING, INFO and DEBUG. Default: DEBUG
         "manage_roles": true, // Have Zappa automatically create and define IAM execution roles and policies. Default true. If false, you must define your own IAM Role and role_name setting.
         "memory_size": 512, // Lambda function memory in MB. Default 512.
         "ephemeral_storage": { "Size": 512 }, // Lambda function ephemeral_storage size in MB, Default 512, Max 10240
         "efs_config": [{ "Arn": "arn:aws:elasticfilesystem:...:access-point/fsap-...", "LocalMountPath": "/mnt/data" }], // Optional EFS configuration. See EFS section for details.
-        "num_retained_versions":5, // Number of published Lambda versions to retain. Default 5. Older versions are deleted on `zappa update` to bound code-storage and (when SnapStart is enabled) snapshot-cache cost. Set to `null` to keep all versions.
+        "num_retained_versions":5, // Number of published Lambda versions to retain. Default 5. Older versions are deleted on `zappa update` to bound code-storage and (when SnapStart is enabled) snapshot-cache cost. Set to `null` to keep all versions. Must be `null` or at least 2 when `snap_start` or `provisioned_concurrency` is enabled, otherwise pruning could try to delete the version Zappa's managed alias still points to.
         "payload_compression": true, // Whether or not to enable API gateway payload compression (default: true)
         "payload_minimum_compression_size": 0, // The threshold size (in bytes) below which payload compression will not be applied (default: 0)
         "prebuild_script": "your_module.your_function", // Function to execute before uploading code
         "profile_name": "your-profile-name", // AWS profile credentials to use. Default 'default'. Removing this setting will use the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables instead.
         "project_name": "MyProject", // The name of the project as it appears on AWS. Defaults to a slugified `pwd`.
+        "provisioned_concurrency": 5, // Number of pre-initialized execution environments to keep warm. Default null (disabled). Provisioned concurrency can only be configured on a published version or alias, so Zappa maintains a "provisioned-concurrency" alias automatically: each `zappa update`/`deploy` configures it on the new version, waits for it to become Ready, then repoints the alias (and cleans up the old version's config) — and points API Gateway at it via `apigateway_lambda_qualifier` unless you've overridden that setting. Cannot be combined with `snap_start` (AWS doesn't support SnapStart with provisioned concurrency), and cannot exceed `lambda_concurrency` if that's also set.
         "remote_env": "s3://my-project-config-files/filename.json", // optional file in s3 bucket containing a flat json object which will be used to set custom environment variables.
         "role_name": "MyLambdaRole", // Name of Zappa execution role. Default <project_name>-<env>-ZappaExecutionRole. To use a different, pre-existing policy, you must also set manage_roles to false.
         "role_arn": "arn:aws:iam::12345:role/app-ZappaLambdaExecutionRole", // ARN of Zappa execution role. Default to None. To use a different, pre-existing policy, you must also set manage_roles to false. This overrides role_name. Use with temporary credentials via GetFederationToken.
         "route53_enabled": true, // Have Zappa update your Route53 Hosted Zones when certifying with a custom domain. Default true.
         "runtime": "python3.14", // Python runtime to use on Lambda. Can be one of: "python3.9", "python3.10", "python3.11", "python3.12", "python3.13", or "python3.14". Defaults to whatever the current Python being used is.
         "s3_bucket": "dev-bucket", // Zappa zip bucket,
         "slim_handler": false, // Useful if project >50M. Set true to just upload a small handler to Lambda and load actual project from S3 at runtime. Default false.
-        "snap_start": "PublishedVersions", // Enable Lambda SnapStart for faster cold starts. Can be "PublishedVersions" or "None". Default "None".
+        "snap_start": "PublishedVersions", // Enable Lambda SnapStart for faster cold starts. Can be "PublishedVersions" or "None". Default "None". SnapStart requires invoking a published version or alias (never `$LATEST`), so Zappa maintains a "snapstart" alias automatically: each `zappa update`/`deploy` publishes a new version, waits for its snapshot to be Active, then repoints the alias — and points API Gateway at it via `apigateway_lambda_qualifier` unless you've overridden that setting. Cannot be combined with `provisioned_concurrency` (AWS doesn't support SnapStart with provisioned concurrency).
         "settings_file": "~/Projects/MyApp/settings/dev_settings.py", // Server side settings file location,
         "tags": { // Attach additional tags to AWS Resources
             "Key": "Value",  // Example Key and value