panic: interface conversion: interface {} is nil, not string

[felipeclopes]

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Terraform Version

0.11.11

Terraform Configuration Files

variable "streams_lambda_function_name" {}
variable "subscription_rabbitmq_queue" {}
variable "subscription_rabbitmq_server" {}

##################################################################################
### Cleaner module
##################################################################################
module "cleaner" {
  source = "./base"

  path = "../dist/cleaner/"
  handler = "cleaner.handler"
  function_name = "cleaner"
  vpc_config = []
  memory_size = 512
  timeout = 600
  log_destination_arn = "${var.log_destination_arn}"
  alarms_topic_arn = "${var.alarms_topic_arn}"
  env = "${var.env}"
  extra_policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [{
      "Effect": "Allow",
      "Action": ["lambda:*"],
      "Resource": "arn:aws:lambda:*"
    },
    {
      "Effect": "Allow",
      "Action": ["lambda:ListFunctions"],
      "Resource": "*"
    },
    {
      "Effect": "Allow",
      "Action": ["dynamodb:*"],
      "Resource": "arn:aws:dynamodb:*"
    }]
}
EOF
}

##################################################################################
### Alerting API Event Consumer
##################################################################################
resource "aws_cloudwatch_event_rule" "every_five_minutes" {
    name = "every-five-minutes"
    description = "Fires every five minutes"
    schedule_expression = "rate(5 minutes)"
}
module "alerting_api_event_consumer" {
  source = "./base"
  path = "../dist/alerting_api_event_consumer/"
  handler = "alerting_api_event_consumer.handler"
  function_name = "alerting-api-event-consumer"
  prefix = "mw-fhai-alerts"
  memory_size = 128
  timeout = 300
  log_destination_arn = "${var.log_destination_arn}"
  alarms_topic_arn = "${var.alarms_topic_arn}"
  env = "${var.env}"
  variables = {
    MI_INTEGRATION_LAMBDA =  "${var.mi_integration_function_name}"
    STREAM_API_LAMBDA = "${var.streams_lambda_function_name}"
    QUEUE_NAME = "${var.subscription_rabbitmq_queue}"
    RABBITMQ_SERVER = "${var.subscription_rabbitmq_server}"
  }
  vpc_config = [{
    subnet_ids = ["${var.subnet_mi}"],
    security_group_ids = ["${var.security_group_mi}"]
  }]
  extra_policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [{
      "Effect": "Allow",
      "Action": ["lambda:*"],
      "Resource": "arn:aws:lambda:*"
    }]
}
EOF
}

resource "aws_cloudwatch_event_target" "call_alerting_api_event_consumer_every_five_minutes" {
    rule = "${aws_cloudwatch_event_rule.every_five_minutes.name}"
    target_id = "alerting_api_event_consumer"
    arn = "${module.alerting_api_event_consumer.arn}"
}

resource "aws_lambda_permission" "allow_cloudwatch_to_call_alerting_api_event_consumer" {
    statement_id = "AllowExecutionFromCloudWatch"
    action = "lambda:InvokeFunction"
    function_name = "${module.alerting_api_event_consumer.function_name}"
    principal = "events.amazonaws.com"
    source_arn = "${aws_cloudwatch_event_rule.every_five_minutes.arn}"
}

##################################################################################
### Payload Indexer
##################################################################################
module "payload-indexer" {
  source = "./base"
  path = "../dist/payload_indexer/"
  handler = "payload_indexer.handler"
  function_name = "payload-indexer"
  memory_size = 512
  timeout = 300
  log_destination_arn = "${var.log_destination_arn}"
  alarms_topic_arn = "${var.alarms_topic_arn}"
  env = "${var.env}"
  variables = {
    ENVIRONMENT =  "${var.env}"
  }
  policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [{
      "Effect": "Allow",
      "Action": ["es:ESHttpPost"],
      "Resource": "*"
    }]
}
EOF
}

Debug Output

Panic Output

https://www.dropbox.com/s/jaemufp07thhs2w/rodrigo_output_logs?dl=0

Expected Behavior

To run as successfully as yesterday

Actual Behavior

panic

Steps to Reproduce

1. terraform plan

Important Factoids

The same configuration ran successfully yesterday; the AWS APIs on the account might be experiencing high usage.

[bflad]

Hi @felipeclopes 👋 Thanks for reporting this and sorry for the trouble.

The panic is occurring from the aws_cloudfront_distribution resource code as noted in the stacktrace here:

2019-02-28T19:14:21.160Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: panic: interface conversion: interface {} is nil, not string
2019-02-28T19:14:21.161Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: 
2019-02-28T19:14:21.161Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: goroutine 10089 [running]:
2019-02-28T19:14:21.163Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: github.com/terraform-providers/terraform-provider-aws/aws.sortInterfaceSlice(0xc00059b340, 0x7, 0x7, 0xf, 0xc000eeb708, 0x1)
2019-02-28T19:14:21.164Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: 	/opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/terraform-providers/terraform-provider-aws/aws/structure.go:1976 +0x364
2019/02/28 19:14:21 [TRACE] dag/walk: vertex "module.lambdas.module.alerting_api_event_consumer.aws_lambda_function.lambda", waiting for: "module.lambdas.module.alerting_api_event_consumer.var.variables"
2019-02-28T19:14:21.164Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: github.com/terraform-providers/terraform-provider-aws/aws.defaultCacheBehaviorHash(0x329d4e0, 0xc0011ab650, 0x1)
2019-02-28T19:14:21.165Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: 	/opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/terraform-providers/terraform-provider-aws/aws/cloudfront_distribution_configuration_structure.go:233 +0xa67
2019-02-28T19:14:21.165Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: github.com/terraform-providers/terraform-provider-aws/vendor/github.com/hashicorp/terraform/helper/schema.(*Set).hash(0xc0008f8400, 0x329d4e0, 0xc0011ab650, 0x3, 0x2)
2019-02-28T19:14:21.166Z [DEBUG] plugin.terraform-provider-aws_v1.60.0_x4: 	/opt/teamcity-agent/work/5d79fe75d4460a2f/src/github.com/terraform-providers/terraform-provider-aws/vendor/github.com/hashicorp/terraform/helper/schema/set.go:211 +0x3d

It seems to be related specifically to the default_cache_behavior configuration block allowed_methods argument. Your timing is quite coincidental though, as we just removed the code above in version 2.0.0 released yesterday. Could you double check no configuration changes occurred there or potentially try updating to 2.0.0 to see if the issue still occurs?

[felipeclopes]

It was fixed by upgrading to version ~>2.0

provider "aws" {
  version = "~> 2.0"
  ...
}

Thank you @bflad!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!