IAM | CodeWisdom

How to create a IAM role with proper policy using terraform?

Trust Policy: Defines who can assume the role.
Role: Defines the role itself.
Permissions Policy: Defines what the role can do by specifying actions and resources.
Policy Attachment: Attaches the permissions policy to the role.

# Step 1: Define the trust policy
data "aws_iam_policy_document" "assume_role" {
  statement {
    effect = "Allow"

    principals {
      type        = "Service"
      identifiers = ["lambda.amazonaws.com"]
    }

    actions = ["sts:AssumeRole"]
  }
}

# Step 2: Define the role
resource "aws_iam_role" "iam_for_lambda" {
  name               = "iam_for_lambda"
  assume_role_policy = data.aws_iam_policy_document.assume_role.json
}

# Step 3: Define the permissions policy
data "aws_iam_policy_document" "lambda_policy" {
  statement {
    effect = "Allow"
    actions = [
      "logs:CreateLogGroup",
      "logs:CreateLogStream",
      "logs:PutLogEvents"
    ]
    resources = ["arn:aws:logs:*:*:*"]
  }
}

# Step 4: Attach the policy to the role
resource "aws_iam_policy" "lambda_policy" {
  name   = "lambda_policy"
  policy = data.aws_iam_policy_document.lambda_policy.json
}

resource "aws_iam_role_policy_attachment" "lambda_policy_attachment" {
  role       = aws_iam_role.iam_for_lambda.name
  policy_arn = aws_iam_policy.lambda_policy.arn
}