Aws IAM Policy

AWS leverages a standard JSON Identity and Access Management (IAM)

policy document format across many services to control authorization

to resources and API actions

terraform

https://www.terraform.io/docs/providers/aws/r/iam_role_policy.html

resource "aws_iam_role_policy" "s3_policy" {
  name = "s3_policy"
  role = "${aws_iam_role.lambda_s3_role.id}"

  policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
        {
            "Sid": "ListObjectsInBucket",
            "Effect": "Allow",
            "Action": ["s3:ListBucket"],
            "Resource": ["arn:aws:s3:::bucket-name"]
        },
        {
            "Sid": "AllObjectActions",
            "Effect": "Allow",
            "Action": "s3:*Object",
            "Resource": ["arn:aws:s3:::bucket-name/*"]
        }
  ]
}
EOF
}

resource "aws_iam_role" "lambda_s3_role" {
  name = "lambda_s3_role"

  assume_role_policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": "sts:AssumeRole",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Effect": "Allow",
      "Sid": ""
    }
  ]
}
EOF
}