setting up event pattern in cloud watch event rule

Question

I am having a problem with my terraform. my lambda is expecting a specific format of message from CloudWatch event rule

resource "aws_cloudwatch_event_rule" "send_hello" {
    name = "say-hi"
    schedule_expression = "cron(0/5 * * * *)"
    is_enabled = true
    event_pattern = <<PATTERN
    {
    "who": "Peter",
    "message_part_1": "hello",
    "message_part_2": "this is the world"
 }
PATTERN
}

I am getting

"who" must be an object or array

my lambda needs to receive an event of

{
   "who": "Peter",
   "message_part_1": "hello",
   "message_part_2": "this is the world"
}

how should I format my event pattern?

ADDITIONAL: the following changes do create the resource, but there is no "who" or "message" in the event when the rule calls lambda

resource "aws_cloudwatch_event_rule" "send_hello" {
    name = "say-hi"
    schedule_expression = "cron(0/5 * * * *)"
    is_enabled = true
    event_pattern = <<PATTERN
    {
    "who": ["Peter"],
    "message_part_1": ["hello"],
    "message_part_2": ["this is the world"]
 }
PATTERN
}

Answer 1

Your send_hello works on schedule, thus event_pattern does not apply. If you want to pass something to your lambda on schedule, you have to specify input_template of your aws_cloudwatch_event_target instead:

Template to customize data sent to the target. Must be valid JSON.