Terraform AWS Lambda Application Module

This module supports the creation of AWS resources for a Lambda Application Architecture style service. This is a work in progress and is currently in a POC implementation.

It requires a Lambda Application Architecture and build/pipeline conventions in order to be of value. An example implementation of this architecture will be provided in the future.

The Lambda Application

The Lambda Application is a design that consists of n functions that have the concept of internal or external entrypoints. External entrypoints are events external to the application which triggers the start of the Lambda Application process. This could be an S3 and/or API gateway event. The current implementation is using an S3 event which is managed outside of the application, hence no apparent configuration variable. It is still uncertain how this will look configuration wise and if external entrypoints encapsulates the language of this architecture, or a more resource orientated naming convention (i.e. s3_event_entrypoints) concept is best. There is some more work trying to understand use cases where an external entrypoint is a concern of the Lambda Application, and how this would impact the current module design.

Internal entrypoints are how functions in the Lambda Application can pass events to each other. All internal entrypoints will use EventBridge as the means to relay events and require some configuration. The configuration for this is still taking shape. It is intended that an sole Event Bus be created, but no support for this exists in the current provider (support is now available see issue #16).

Context

Given the early stage of this module, it is advised this not be used in production until further examples can be provided. This is an opinionated module and as such requires a context for it to be an effective way to provision Lambda resources. It has only tested with the Python 3.8 & Nodejs 18 runtimes and there are some questions on how other language runtimes will impact the design of this module. Please do reach out of you are curious or interested in contributing to the work being done here.

Artifactory Module

A stand alone artifactory module has been provided as a stand alone module to cater for the creation of an artifactory bucket in a different AWS account. The README contains more info.

Alb Module

A stand alone alb module has been provided as a stand alone module to cater for the creation of an Application load balancer that supports Lambda target type. The README contains more info.

---

Requirements

Name	Version
terraform	>= 1.3.0
aws	>= 5.32.0, <6.0.0

Providers

Name	Version
aws	>= 5.32.0, <6.0.0

Modules

Name	Source	Version
lambda_datastore	github.com/hyprnz/terraform-aws-data-storage-module	v4.2.0

Inputs

Name	Description	Type	Default	Required
application_name	Repo name of the lambda application.	string	n/a	yes
application_runtime	Lambda runtime for the application.	string	n/a	yes
application_version	Version of the function(s) deployed for the application.	string	n/a	yes
artifact_bucket	Bucket that stores function artifacts. Includes layer dependencies.	string	n/a	yes
artifact_bucket_key	File name key of the artifact to load.	string	n/a	yes
lambda_functions_config	Map of functions and associated configurations.	map(object({ description = optional(string) handler = string enable_vpc = bool function_memory = optional(string) function_timeout = optional(number) log_format = optional(string, "Text") application_log_level = optional(string) system_log_level = optional(string) enable_lambda_insights_monitoring = optional(bool, null) function_concurrency_limit = optional(number) }))	n/a	yes
additional_layers	A list of layer ARN's (with or without aliases) to add to all functions within the Lambda application. Provides the ability to add dependencies for additional functionality such as monitoring and observability.	list(string)	[]	no
alb_lambda_listener_arn	Listener ARN of ALB	string	""	no
alias_description	Name of the alias being created	string	"Default alias"	no
alias_name	Name of the alias being created	string	"live"	no
api_gateway_cors_configuration	Cross-origin resource sharing (CORS) configuration.	object({ allow_credentials = optional(bool, null) allow_headers = optional(set(string), null) allow_methods = optional(set(string), null) allow_origins = optional(set(string), null) expose_headers = optional(set(string), null) max_age = optional(number, null) })	{}	no
api_gateway_custom_domain_name	A custom domain name for the API gateway. If not provided will use the default AWS one. Requires api_gateway_custom_domain_zone_id to be provided	string	""	no
api_gateway_custom_domain_zone_id	The Route 53 hosted zone id for the API gatewy custom domain. Must be provided and be valid, if the api_gateway_custom_domain_name is set	string	""	no
api_gateway_route_config	The API Gateway route configuration. The keys should be the names of the Lambda functions that triggered by the API Gateway	map(object({ # https://docs.aws.amazon.com/apigateway/latest/developerguide/simple-calc-lambda-api.html operation_name = optional(string, null) methods = optional(set(string), ["ANY"]) }))	{}	no
application_env_vars	Map of environment variables required by any function in the application.	map(any)	{}	no
application_memory	Memory allocated to all functions in the application. Defaults to 128.	number	128	no
application_timeout	Timeout in seconds for all functions in the application. Defaults to 3.	number	3	no
aws_cloudwatch_log_group_retention_in_days	The retention period in days of all log group created for each function. Defaults to 30.	number	30	no
create_dynamodb_table	Whether or not to enable DynamoDB resources	bool	false	no
create_rds_instance	Controls if an RDS instance should be provisioned. Will take precedence if this and use_rds_snapshot are both true.	bool	false	no
create_s3_bucket	Controls if an S3 bucket should be provisioned	bool	false	no
custom_policy_description	Allows to override the custom Lambda policy's description	string	""	no
custom_policy_document	A valid policy json string that defines additional actions required by the execution role of the Lambda function	string	""	no
datastore_tags	Tags for all datastore resources	map(any)	{}	no
dynamodb_attributes	Additional DynamoDB attributes in the form of a list of mapped values	list(any)	[]	no
dynamodb_autoscale_max_read_capacity	DynamoDB autoscaling max read capacity	number	20	no
dynamodb_autoscale_max_write_capacity	DynamoDB autoscaling max write capacity	number	20	no
dynamodb_autoscale_min_read_capacity	DynamoDB autoscaling min read capacity	number	5	no
dynamodb_autoscale_min_write_capacity	DynamoDB autoscaling min write capacity	number	5	no
dynamodb_autoscale_read_target	The target value (in %) for DynamoDB read autoscaling	number	50	no
dynamodb_autoscale_write_target	The target value (in %) for DynamoDB write autoscaling	number	50	no
dynamodb_billing_mode	DynamoDB Billing mode. Can be PROVISIONED or PAY_PER_REQUEST	string	"PROVISIONED"	no
dynamodb_enable_autoscaler	Whether or not to enable DynamoDB autoscaling	bool	false	no
dynamodb_enable_encryption	Enable DynamoDB server-side encryption	bool	true	no
dynamodb_enable_insights	Enables Contributor Insights for Dynamodb	bool	false	no
dynamodb_enable_point_in_time_recovery	Enable DynamoDB point in time recovery	bool	true	no
dynamodb_enable_streams	Enable DynamoDB streams	bool	false	no
dynamodb_global_secondary_index_map	Additional global secondary indexes in the form of a list of mapped values	any	[]	no
dynamodb_hash_key	DynamoDB table Hash Key	string	""	no
dynamodb_hash_key_type	Hash Key type, which must be a scalar type: S, N, or B for (S)tring, (N)umber or (B)inary data	string	"S"	no
dynamodb_local_secondary_index_map	Additional local secondary indexes in the form of a list of mapped values	list(any)	[]	no
dynamodb_range_key	DynamoDB table Range Key	string	""	no
dynamodb_range_key_type	Range Key type, which must be a scalar type: S, N or B for (S)tring, (N)umber or (B)inary data	string	"S"	no
dynamodb_stream_view_type	When an item in a table is modified, what information is written to the stream	string	""	no
dynamodb_table_name	DynamoDB table name. Must be supplied if creating a dynamodb table	string	""	no
dynamodb_tags	Additional tags e.g map(BusinessUnit,XYX)	map(any)	{}	no
dynamodb_ttl_attribute	DynamoDB table ttl attribute	string	"Expires"	no
dynamodb_ttl_enabled	Whether ttl is enabled or disabled	bool	true	no
enable_api_gateway	Allow to create api-gateway	bool	false	no
enable_datastore	Enables the data store module that will provision data storage resources	bool	true	no
enable_lambda_insights_monitoring	Determine if enhanced monitoring (Lambda Insights) is enabled for all functions, can be overwritten by the function configuration.	bool	false	no
enable_load_balancer	Allow to create load balancer	bool	false	no
external_entrypoint_config	Map of configurations of external entrypoints.	map(object({ name = string description = optional(string, null) event_pattern_json = optional(map(any), null) schedule_expression = optional(string, null) event_bus_name = string source_account = optional(string, null) }))	{}	no
iam_resource_path	The path for IAM roles and policies	string	"/"	no
internal_entrypoint_config	Map of configurations of internal entrypoints.	map(object({ name = string description = optional(string, null) event_pattern_json = optional(any, {}) schedule_expression = optional(string, "") }))	{}	no
lambda_alb_config	Contains entry point lambda function key	map(string)	{}	no
lambda_insights_extension_layer	The arn of the Lambda Insights Extension layer	string	""	no
layer_artifact_key	File name key of the layer artifact to load.	string	""	no
msk_arn	the MSK source arn for all lambda requires MSK	string	""	no
msk_event_source_config	Map of configurations of MSK event source for each lambda	map(set(object({ event_source_arn = optional(string, null) topic = string starting_position = optional(string, "LATEST") batch_size = optional(number, null) consumer_group_id_prefix = optional(string, "") enabled = optional(bool, true) })))	{}	no
parameter_store_path	SSM parameter path	string	""	no
rds_allocated_storage	Amount of storage allocated to RDS instance	number	100	no
rds_apply_immediately	Specifies whether any database modifications are applied immediately, or during the next maintenance window. Defaults to false.	bool	false	no
rds_auto_minor_version_upgrade	Indicates that minor engine upgrades will be applied automatically to the DB instance during the maintenance window. Defaults to true.	bool	true	no
rds_backup_retention_period	The backup retention period in days	number	7	no
rds_backup_window	The daily time range (in UTC) during which automated backups are created if they are enabled. Example: '09:46-10:16'. Must not overlap with maintenance_window	string	"16:19-16:49"	no
rds_cloudwatch_logs_exports	Which RDS logs should be sent to CloudWatch. The default is empty (no logs sent to CloudWatch)	set(string)	[]	no
rds_database_name	The name of the database. Can only contain alphanumeric characters	string	""	no
rds_enable_deletion_protection	If the DB instance should have deletion protection enabled. The database can't be deleted when this value is set to true. The default is false.	bool	false	no
rds_enable_performance_insights	Controls the enabling of RDS Performance insights. Default to true	bool	true	no
rds_enable_storage_encryption	Specifies whether the DB instance is encrypted	bool	false	no
rds_engine	The Database engine for the rds instance	string	"postgres"	no
rds_engine_version	The version of the database engine.	string	"11"	no
rds_final_snapshot_identifier	The name of your final DB snapshot when this DB instance is deleted. Must be provided if rds_skip_final_snapshot is set to false. The value must begin with a letter, only contain alphanumeric characters and hyphens, and not end with a hyphen or contain two consecutive hyphens.	string	null	no
rds_iam_authentication_enabled	Controls whether you can use IAM users to log in to the RDS database. The default is false	bool	false	no
rds_identifier	Identifier of datastore instance	string	""	no
rds_instance_class	The instance type to use	string	"db.t3.small"	no
rds_iops	The amount of provisioned IOPS. Setting this implies a storage_type of 'io1'	number	0	no
rds_max_allocated_storage	The upper limit to which Amazon RDS can automatically scale the storage of the DB instance. Configuring this will automatically ignore differences to allocated_storage. Must be greater than or equal to allocated_storage or 0 to disable Storage Autoscaling.	number	200	no
rds_monitoring_interval	The interval, in seconds, between points when Enhanced Monitoring metrics are collected for the DB instance. To disable collecting Enhanced Monitoring metrics, specify 0. The default is 0. Valid Values: 0, 1, 5, 10, 15, 30, 60.	number	0	no
rds_monitoring_role_arn	The ARN for the IAM role that permits RDS to send enhanced monitoring metrics to CloudWatch Logs. Must be specified if monitoring_interval is non-zero.	string	""	no
rds_multi_az	Specifies if the RDS instance is multi-AZ.	bool	false	no
rds_option_group_name	Name of the DB option group to associate	string	null	no
rds_parameter_group_family	Name of the DB family (engine & version) for the parameter group. eg. postgres11	string	null	no
rds_parameter_group_name	Name of the DB parameter group to create and associate with the instance	string	null	no
rds_parameter_group_parameters	Map of parameters that will be added to this database's parameter group. Parameters set here will override any AWS default parameters with the same name. Requires rds_parameter_group_name and rds_parameter_group_family to be set as well. Parameters should be provided as a key value pair within this map. eg "param_name" : "param_value". Default is empty and the AWS default parameter group is used.	map(any)	{}	no
rds_password	RDS database password for the user	string	""	no
rds_security_group_ids	A List of security groups to bind to the rds instance	list(string)	[]	no
rds_skip_final_snapshot	Determines whether a final DB snapshot is created before the DB instance is deleted. If true is specified, no DBSnapshot is created. If false is specified, a DB snapshot is created before the DB instance is deleted, using the value from final_snapshot_identifier	bool	true	no
rds_storage_encryption_kms_key_arn	The ARN for the KMS encryption key. If creating an encrypted replica, set this to the destination KMS ARN. If storage_encrypted is set to true and kms_key_id is not specified the default KMS key created in your account will be used	string	""	no
rds_subnet_group	Subnet group for RDS instances	string	""	no
rds_tags	Additional tags for rds datastore resources	map(any)	{}	no
rds_username	RDS database user name	string	""	no
s3_bucket_name	The name of the bucket. It is recommended to add a namespace/suffix to the name to avoid naming collisions	string	""	no
s3_enable_versioning	If versioning should be configured on the bucket	bool	true	no
s3_tags	Additional tags to be added to the s3 resources	map(any)	{}	no
service_target_group_name	The service target group attached to application load balancer listener	string	""	no
service_target_group_path	The target path attached to the service target group	string	""	no
ssm_kms_key_arn	Either he customer managed KMS or AWS manages key arn used for encrypting SecureSting parameters	string	""	no
tags	Additional tags that are added to all resources in this module.	map(any)	{}	no
tracking_config	Sets the passing of sample and tracing of calls, possible values are Passthrough(default) or Active	string	"PassThrough"	no
use_rds_snapshot	Controls if an RDS snapshot should be used when creating the rds instance. Will use the latest snapshot of the rds_identifier variable.	bool	false	no
vpc_security_group_ids	List of security group IDs associated with the Lambda function	list(string)	[]	no
vpc_subnet_ids	List of subnet IDs associated with the Lambda function	list(string)	[]	no

Outputs

Name	Description
api_gateway_arn	The ARN of the v2 API Gateway resource
api_gateway_endpoint	The HTTP endpoint of the v2 API Gateway resource
api_gateway_id	The ID of the v2 API Gateway resource
api_gateway_integration_ids	The ID's of the v2 API Gateway integration resource
api_gateway_name	The name of the v2 API Gateway resource
api_gateway_stage_api_id	The API ID of the v2 API Gateway stage resource
api_gateway_stage_invoke_url	The API ID of the v2 API Gateway stage resource
domain_id	The ID of the custom domain name used for the v2 API gateway resource
lambda_function_alias_arns	ARNs of the Lambda function aliases
lambda_function_arns	ARNs of the Lambda functions
lambda_function_names	Names of the Lambda functions

---

License

See LICENSE for full details.

Copyright 2020 Hypr NZ

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Copyright © 2020 Hypr NZ