feat: added lambda logging config

Allow configuring aws lambda logging

Sample:

```
logging_config = {
  log_format            = "JSON"
  application_log_level = "INFO"
  system_log_level      = "WARN"
}
```

Author: thisismana

README.md

@@ -415,6 +415,7 @@ No modules.
 | <a name="input_kms_key_arn"></a> [kms\_key\_arn](#input\_kms\_key\_arn) | Amazon Resource Name (ARN) of the AWS Key Management Service (KMS) key that is used to encrypt environment variables. If this configuration is not provided when environment variables are in use, AWS Lambda uses a default service key. If this configuration is provided when environment variables are not in use, the AWS Lambda API does not save this configuration and Terraform will show a perpetual difference of adding the key. To fix the perpetual difference, remove this configuration. | `string` | `""` | no |
 | <a name="input_lambda_at_edge"></a> [lambda\_at\_edge](#input\_lambda\_at\_edge) | Enable Lambda@Edge for your Node.js or Python functions. Required trust relationship and publishing of function versions will be configured. | `bool` | `false` | no |
 | <a name="input_layers"></a> [layers](#input\_layers) | List of Lambda Layer Version ARNs (maximum of 5) to attach to your Lambda Function. | `list(string)` | `[]` | no |
+| <a name="input_logging_config"></a> [logging\_config](#input\_logging\_config) | The function's Amazon CloudWatch Logs configuration settings. | <pre>object({<br/>    log_format            = string<br/>    application_log_level = optional(string, null)<br/>    log_group             = optional(string, null)<br/>    system_log_level      = optional(string, null)<br/>  })</pre> | `null` | no |
 | <a name="input_memory_size"></a> [memory\_size](#input\_memory\_size) | Amount of memory in MB your Lambda Function can use at runtime. | `number` | `128` | no |
 | <a name="input_package_type"></a> [package\_type](#input\_package\_type) | The Lambda deployment package type. Valid values are Zip and Image. | `string` | `"Zip"` | no |
 | <a name="input_publish"></a> [publish](#input\_publish) | Whether to publish creation/change as new Lambda Function Version. | `bool` | `false` | no |

examples/complete/main.tf

@@ -37,6 +37,11 @@ module "lambda" {
     }
   }
 
+  logging_config = {
+    log_format            = "JSON"
+    application_log_level = "INFO"
+  }
+
   // AWS Systems Manager (SSM) Parameter Store
   ssm = {
     parameter_names = ["/internal/params", "/external/params"]

examples/fixtures/context/index.js

@@ -1,4 +1,14 @@
-exports.handler =  async function(event, context) {
-  console.log("EVENT: \n" + JSON.stringify(event, null, 2))
-  return context.logStreamName
+exports.handler = async function (event, context) {
+    const logMessage = {
+        "message": "Hello from Lambda!",
+        "level": "INFO",
+        "timestamp": new Date().toISOString(),
+        "context": {
+            "functionName": context.functionName,
+            "functionVersion": context.functionVersion,
+        },
+        "event": event
+    }
+    console.log(JSON.stringify(logMessage, null, 2))
+    return context.logStreamName
 }

main.tf

@@ -158,6 +158,16 @@ resource "aws_lambda_function" "lambda_external_lifecycle" {
     }
   }
 
+  dynamic "logging_config" {
+    for_each = var.logging_config == null ? [] : [var.logging_config]
+    content {
+      application_log_level = logging_config.value.application_log_level
+      log_format            = logging_config.value.log_format
+      log_group             = logging_config.value.log_group
+      system_log_level      = logging_config.value.system_log_level
+    }
+  }
+
   // create the CloudWatch log group first so it's no create automatically
   // by AWS Lambda
   depends_on = [aws_cloudwatch_log_group.lambda]

variables.tf

@@ -249,6 +249,21 @@ variable "vpc_config" {
   })
 }
 
+variable "logging_config" {
+  description = "The function's Amazon CloudWatch Logs configuration settings."
+  default     = null
+  type = object({
+    log_format            = string
+    application_log_level = optional(string, null)
+    log_group             = optional(string, null)
+    system_log_level      = optional(string, null)
+  })
+  validation {
+    condition     = var.logging_config == null || (var.logging_config.log_format == "JSON" || var.logging_config.log_format == "Text")
+    error_message = "log_format must be either 'JSON' or 'Text'"
+  }
+}
+
 variable "iam_role_name" {
   description = "Override the name of the IAM role for the function. Otherwise the default will be your function name with the region as a suffix."
   default     = null