seahaven-site/terraform/iam_github_deploy.tf

data "aws_iam_policy_document" "github_deploy_assume" {
  # Legacy branch trust. Remove after one deploy through cd-hcp-static has
  # succeeded. The branch subject stays until EnvironmentProd is applied.
  statement {
    sid     = "LegacyBranch"
    effect  = "Allow"
    actions = ["sts:AssumeRoleWithWebIdentity"]

    principals {
      type        = "Federated"
      identifiers = [data.aws_iam_openid_connect_provider.github.arn]
    }

    condition {
      test     = "StringEquals"
      variable = "token.actions.githubusercontent.com:aud"
      values   = ["sts.amazonaws.com"]
    }

    condition {
      test     = "StringLike"
      variable = "token.actions.githubusercontent.com:sub"
      values   = ["repo:${var.github_repo}:ref:refs/heads/${var.github_deploy_branch}"]
    }
  }

  statement {
    sid     = "EnvironmentProd"
    effect  = "Allow"
    actions = ["sts:AssumeRoleWithWebIdentity"]

    principals {
      type        = "Federated"
      identifiers = [data.aws_iam_openid_connect_provider.github.arn]
    }

    condition {
      test     = "StringEquals"
      variable = "token.actions.githubusercontent.com:aud"
      values   = ["sts.amazonaws.com"]
    }

    condition {
      test     = "StringEquals"
      variable = "token.actions.githubusercontent.com:sub"
      values   = ["repo:${var.github_repo}:environment:prod"]
    }

    condition {
      test     = "StringLike"
      variable = "token.actions.githubusercontent.com:job_workflow_ref"
      values   = ["Sea-Haven-Industries/.github/.github/workflows/cd-hcp-static.yaml@*"]
    }
  }
}

resource "aws_iam_policy" "github_deploy_boundary" {
  name        = "seahaven-site-githubdeploy-boundary"
  path        = "/tf-managed/"
  description = "Permissions boundary for githubdeploy-seahaven-site"
  policy      = data.aws_iam_policy_document.github_deploy.json

  # Request tag the hcptf apply role requires before it may CreatePolicy.
  tags = {
    BoundaryFor = "githubdeploy-seahaven-site"
  }
}

resource "aws_iam_role" "github_deploy" {
  name                 = local.deploy_role
  path                 = "/tf-managed/"
  description          = "GitHub Actions content-deploy role for ${var.github_repo} Environment prod"
  assume_role_policy   = data.aws_iam_policy_document.github_deploy_assume.json
  permissions_boundary = aws_iam_policy.github_deploy_boundary.arn
  max_session_duration = 3600
}

data "aws_iam_policy_document" "github_deploy" {
  statement {
    sid    = "OriginBucketObjects"
    effect = "Allow"
    actions = [
      "s3:GetObject",
      "s3:PutObject",
      "s3:DeleteObject",
      "s3:GetObjectTagging",
      "s3:PutObjectTagging",
    ]
    resources = ["${aws_s3_bucket.origin.arn}/*"]
  }

  statement {
    sid    = "OriginBucketList"
    effect = "Allow"
    actions = [
      "s3:ListBucket",
      "s3:GetBucketLocation",
    ]
    resources = [aws_s3_bucket.origin.arn]
  }

  statement {
    sid    = "InvalidateDistribution"
    effect = "Allow"
    actions = [
      "cloudfront:CreateInvalidation",
      "cloudfront:GetDistribution",
      "cloudfront:GetInvalidation",
    ]
    resources = [aws_cloudfront_distribution.site.arn]
  }

  statement {
    sid    = "ReadDeployContract"
    effect = "Allow"
    actions = [
      "ssm:GetParameter",
      "ssm:GetParameters",
    ]
    resources = ["arn:aws:ssm:${var.aws_region}:${local.account_id}:parameter/seahaven-site/deploy/*"]
  }
}

resource "aws_iam_role_policy" "github_deploy" {
  name   = "seahaven-site-content-deploy"
  role   = aws_iam_role.github_deploy.id
  policy = data.aws_iam_policy_document.github_deploy.json
}