CFDNS

About

Non-Official GO CloudFlare DNS API client. It was created because the official API is not stable and breaks its consumers multiple times a year. Some of the breaks are immediately apparent because the compiler itself can find the problem, sometimes the expectation can't be detected automatically, while when the returned error is changed, leading to unexpected behavior in code that might be mission-critical.

This library is being used on a system that manages dozens of domains with thousands of records, and makes hundreds of changes per day. It show up to be reliable, and eliminating multiple issues that were present when the official library was being used.

The original library also has an implementation that requires an unbounded amount of memory when listing records. This implementation is O(1) in memory for all operations.

Exponential back-off is implemented and heavily tested.

This library was designed to support only the DNS service.

Project Status

This version is stable, being used in production. It will provide backwards compatibility according to go module conventions.

How to Get

go get github.com/simplesurance/cfdns@latest

How to Use

Listing Records

Listing records uses the Iterator pattern to completely abstract the complexity of pagination, while keeping constant memory usage, even when the resulting list is arbitrarily large.

ctx := context.Background()
apitoken := os.Getenv("CFTOKEN")

creds, err := cfdns.APIToken(apitoken)
if err != nil {
	panic(err)
}

client := cfdns.NewClient(creds)

iter := client.ListZones(&cfdns.ListZonesRequest{})
for {
	zone, err := iter.Next(ctx)
	if err != nil {
		if errors.Is(err, io.EOF) {
			break
		}

		panic(err)
	}

	fmt.Printf("Found zone %s\n", zone.Name)
}

Create and Delete a DNS Record

All methods that do not return a list receive a context and a request struct and return a struct and an error.

ctx := context.Background()
apitoken := os.Getenv("TEST_CF_APITOKEN")
testZoneID := os.Getenv("TEST_CF_ZONE_ID")

creds, err := cfdns.APIToken(apitoken)
if err != nil {
	panic(err)
}

client := cfdns.NewClient(creds)

resp, err := client.CreateRecord(ctx, &cfdns.CreateRecordRequest{
	ZoneID:  testZoneID,
	Name:    "example-record",
	Type:    "CNAME",
	Content: "github.com",
	Proxied: false,
	Comment: "Created by cfdns example",
	TTL:     time.Duration(30 * time.Minute),
})
if err != nil {
	panic(err)
}

fmt.Printf("Created DNS record %s", resp.Name)

// cleanup
_, _ = client.DeleteRecord(ctx, &cfdns.DeleteRecordRequest{
	ZoneID:   testZoneID,
	RecordID: resp.ID,
})

// Output: Created DNS record example-record.simplesurance.top

Error Handling

Rules for errors returned are as follows:

1. If the error response came from sending the HTTP response to the CloudFlare, even if it is an invalid response, the error is HTTPError;
2. If the response is a valid CloudFlare API response, then the error is also a CloudFlareError (so it is both HTTPError and CloudFlareError);
3. If not valid HTTP response could be obtained from the server, then some other error is returned.

In all cases, the caller MUST use errors.As() to get either the HTTPError or CloudFlareError object.

HTTPError

All errors that result from calling the CloudFlare REST API allow reading the HTTP response that caused it.

ctx := context.Background()
apitoken := os.Getenv("TEST_CF_APITOKEN")
testZoneID := os.Getenv("TEST_CF_ZONE_ID")

creds, err := cfdns.APIToken(apitoken)
if err != nil {
	panic(err)
}

client := cfdns.NewClient(creds)

_, err = client.CreateRecord(ctx, &cfdns.CreateRecordRequest{
	ZoneID:  testZoneID,
	Name:    "invalid name",
	Type:    "A",
	Content: "github.com",
	Comment: "Created by cfdns example",
	TTL:     30 * time.Minute,
})

httpErr := cfdns.HTTPError{}
if !errors.As(err, &httpErr) {
	panic("not an HTTP error")
}

fmt.Printf("Got HTTP error %v", httpErr.Code) // can also access response headers and raw response body

// Output: Got HTTP error 400

CloudFlareError

ctx := context.Background()
apitoken := os.Getenv("TEST_CF_APITOKEN")
testZoneID := os.Getenv("TEST_CF_ZONE_ID")

creds, err := cfdns.APIToken(apitoken)
if err != nil {
	panic(err)
}

client := cfdns.NewClient(creds)

_, err = client.CreateRecord(ctx, &cfdns.CreateRecordRequest{
	ZoneID:  testZoneID,
	Name:    "invalid name",
	Type:    "A",
	Content: "github.com",
	Comment: "Created by cfdns example",
	TTL:     30 * time.Minute,
})

cfErr := cfdns.CloudFlareError{}
if !errors.As(err, &cfErr) {
	panic("not a CloudFlareError")
}

fmt.Printf("Got HTTP error %v\n", cfErr.HTTPError.Code) // can also access response headers and raw response body

for _, cfe := range cfErr.Errors {
	fmt.Printf("- CF error %d: %s\n", cfe.Code, cfe.Message) // can also access response headers and raw response body
}

// Output:
// Got HTTP error 400
// - CF error 9005: Content for A record must be a valid IPv4 address.