aws_ami data source with a name_regex including ** causes terraform to crash

[paulte]

Low priority bug report. It looks like name_regex within aws_ami doesn't handle the regular expression of **

I'm not suggesting there's a use case where ** would be considered required / desirable, more that it would be preferable that it didn't crash terraform.

Terraform Version

Terraform v0.7.7

Affected Resource(s)

• aws_ami

If this issue appears to affect multiple resources, it may be an issue with Terraform's core, so please mention this.

Terraform Configuration Files

provider "aws" {
    region="eu-west-1"
}

data "aws_ami" "example" {
  owners = ["self"]
  name_regex = "^example**"
  most_recent = true
}

output "myami" {
        value = "${data.aws_ami.example.id}"
}

Panic Output

https://gist.github.com/paulte/73d2709161842737aa6fd4810664e80b

Expected Behavior

The regular expression ** should be considered equivalent to * and not crash terraform

Actual Behavior

Terraform crash

Steps to Reproduce

1. terraform apply

[apparentlymart]

Relevant chunk of the Panic output, for easier reference:

2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: panic: regexp: Compile(`^example**`): error parsing regexp: invalid nested repetition operator: `**`
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: 
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: goroutine 86 [running]:
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: panic(0x2310fa0, 0xc420446d70)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/go/src/runtime/panic.go:500 +0x1a1
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: regexp.MustCompile(0xc420698a50, 0xa, 0xc420698d30)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/go/src/regexp/regexp.go:237 +0x17a
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: github.com/hashicorp/terraform/builtin/providers/aws.dataSourceAwsAmiRead(0xc4205a2de0, 0x2220fc0, 0xc4204b6180, 0xc00000000000007, 0x0)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/gopath/src/github.com/hashicorp/terraform/builtin/providers/aws/data_source_aws_ami.go:240 +0x338
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: github.com/hashicorp/terraform/helper/schema.(*Resource).ReadDataApply(0xc42026c9c0, 0xc420697380, 0x2220fc0, 0xc4204b6180, 0xc42057d9d8, 0x1, 0x0)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/gopath/src/github.com/hashicorp/terraform/helper/schema/resource.go:207 +0xda
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: github.com/hashicorp/terraform/helper/schema.(*Provider).ReadDataApply(0xc420274030, 0xc42040d380, 0xc420697380, 0x0, 0x18, 0x18)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/gopath/src/github.com/hashicorp/terraform/helper/schema/provider.go:317 +0x91
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: github.com/hashicorp/terraform/plugin.(*ResourceProviderServer).ReadDataApply(0xc4201ca080, 0xc420698600, 0xc420698c60, 0x0, 0x0)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/gopath/src/github.com/hashicorp/terraform/plugin/resource_provider.go:537 +0x4e
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: reflect.Value.call(0xc420485620, 0xc4201be040, 0x13, 0x2a8503f, 0x4, 0xc420795ed0, 0x3, 0x3, 0x22fb6e0, 0xc4205a2cc0, ...)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/go/src/reflect/value.go:434 +0x5c8
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: reflect.Value.Call(0xc420485620, 0xc4201be040, 0x13, 0xc420795ed0, 0x3, 0x3, 0xc42073e014, 0x100000000, 0xc4204bff01)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/go/src/reflect/value.go:302 +0xa4
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: net/rpc.(*service).call(0xc42000a3c0, 0xc42000a380, 0xc4203784a0, 0xc4203ae500, 0xc4203765e0, 0x22230c0, 0xc420698600, 0x16, 0x2223100, 0xc420698c60, ...)
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/go/src/net/rpc/server.go:383 +0x148
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7: created by net/rpc.(*Server).ServeCodec
2016/10/25 22:54:37 [DEBUG] plugin: terraform.0.7.7:    /opt/go/src/net/rpc/server.go:477 +0x421

[kwilczynski]

@paulte hi there! Thank you for getting in touch!

I have added a pre-flight, so to speak, validation of the regular expression that is passed down via the name_regex attribute. It should help to catch issues earlier in the process. Sorry for any troubles!

[stack72]

Closed via #9622

[kwilczynski]

@paulte hi there! Just to add for the record - the ** is definitely not a valid operation, and would trip a lot of regular expression engines (e.g. JavaScript, Perl, Ruby, etc.), thus we cannot support it, but we can fail early to improve the feedback to the user before the issue manifests itself.

[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 have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.