Writing new DNS providers
Last updated
Last updated
Writing a new DNS provider is a relatively straightforward process. You essentially need to implement the and the system takes care of the rest.
Please do note that if you submit a new provider you will be assigned bugs related to the provider in the future (unless you designate someone else as the maintainer). More details.
Please follow the and the .
I'll ignore all the small stuff and get to the point.
A typical provider implements 3 methods and DNSControl takes care of the rest:
GetZoneRecords() -- Download the list of DNS records and return them as a list of RecordConfig structs.
GetZoneRecordsCorrections() -- Generate a list of corrections.
GetNameservers() -- Query the API and return the list of parent nameservers.
These three functions are all that's needed for dnscontrol preview
and dnscontrol push.
The goal of GetZoneRecords() is to download all the DNS records,
convert them to models.RecordConfig format, and return them as one big list
(models.Records).
The goal of GetZoneRecordsCorrections() is to return a list of
corrections. Each correction is a text string describing the change
("Delete CNAME record foo") and a function that, if called, will
make the change (i.e. call the API and delete record foo). dnscontrol preview
simply prints the text strings. dnscontrol push prints the
strings and calls the functions. Because of how Go's functions work,
the function will have everything it needs to make the change.
Pretty cool, eh?
Calculating the difference between existing and desired is difficult. Luckily
the work is done for you. GetZoneRecordsCorrections() calls a a function in
the pkg/diff2 module that generates a list of changes (usually an ADD,
CHANGE, or DELETE) that can easily be turned into the API calls mentioned
previously.
So, what does all this mean?
It basically means that writing a provider is as simple as writing
code that (1) downloads the existing records, (2) converts each
records into models.RecordConfig, (3) write functions that perform
adds, changes, and deletions.
If you are new to Go, there are plenty of providers you can copy from. In fact, many non-Go programmers.
Now that you understand the general process, here are the details.
A provider can be a DnsProvider, a Registrar, or both. We recommend you write the DnsProvider first, release it, and then write the Registrar if needed.
If you have any questions, please discuss them in the GitHub issue related to the request for this provider.
This document is constantly being updated. Please let us know what was confusing so we can update this document with advice for future authors (or even better send a PR!).
It's a good idea to start by copying a similar provider.
How can you tell a provider is similar?
Each DNS provider's API falls into one of 4 category. Some update one DNS record at a time. Others, the only change they permit is to upload the entire zone even if only one record changed! Others are somewhere in between: all records at a label must be updated at once, or all records in a RecordSet (the label + rType).
In summary, provider APIs basically fall into four general categories:
Updates are done one record at a time (Record)
Updates are done one label at a time (Label)
Updates are done one label+type at a time (RecordSet)
Updates require the entire zone to be uploaded (Zone).
To determine your provider's category, review your API documentation.
To determine an existing provider's category, see which diff2.By*() function is used.
DNSControl provides 4 helper functions that do all the hard work for
you. As input, they take the existing zone (what was downloaded via
the API) and the desired zone (what is in dnsconfig.js). They
return a list of instructions. Implement handlers for the instructions
and DNSControl is able to perform dnscontrol push.
The functions are:
diff2.ByRecord() -- Updates are done one DNS record at a time. New records are added. Changes and deletes refer to an ID assigned to the record by the provider.
diff2.ByLabel() -- Updates are done for an entire label. Adds and changes are done by sending one or more records that will appear at that label (i.e. www.example.com). Deletes delete all records at that label.
diff2.ByRecordSet() -- Similar to ByLabel() but updates are done on the label+type level. If www.example.com has 2 A records and 2 MX records, updates must replace all the A records, or all the MX records, or add records of a different type.
diff2.ByZone() -- Updates are done by uploading the entire zone every time.
The file pkg/diff2/diff2.go has instructions about how to use the diff2 system.
Create a directory for the provider called providers/name wherename is all lowercase and represents the commonly-used name for
the service.
The main driver should be called providers/name/nameProvider.go.
The API abstraction is usually in a separate file (often calledapi.go).
Directory names should be consitent. It should be all lowercase and match the ALLCAPS provider name. Avoid _s.
If you are implementing a DNS Service Provider:
The function GetDomainCorrections() is a bit interesting. It returns
a list of corrections to be made. These are in the form of functions
that DNSControl can call to actually make the corrections.
If you are implementing a DNS Registrar:
The function GetRegistrarCorrections() returns
a list of corrections to be made. These are in the form of functions
that DNSControl can call to actually make the corrections.
Make sure the existing unit tests work. Add unit tests for any complex algorithms in the new code.
Run the unit tests with this command:
This is the most important kind of testing when adding a new provider. Integration tests use a test account and a test domain.
All records will be deleted from the test domain! Use a OTE domain or a real domain that isn't otherwise in use and can be destroyed.
Add the creds.json info required for this provider in the form of environment variables.
Now you can run the integration tests.
For example, test BIND:
(BIND is a good place to start since it doesn't require API keys.)
This will run the tests on Amazon AWS Route53:
Some useful go test flags:
Run only certain tests using the -start and -end flags.
Rather than running all the tests, run just the tests you want.
These flags must be after the -profile FOO flag.
Example: go test -v -verbose -profile ROUTE53 -start 10 -end 20 run tests 10-20 inclusive.
Example: go test -v -verbose -profile ROUTE53 -start 5 -end 5 runs only test 5.
Example: go test -v -verbose -profile ROUTE53 -start 20 skip the first 19 tests.
Example: go test -v -verbose -profile ROUTE53 -end 20 only run the first 20 tests.
Slow tests? Add -timeout n to increase the timeout for tests
go test kills the tests after 10 minutes by default. Some providers need more time.
This flag must be before the -verbose flag. Usually it is the first flag after go test.
Example: go test -timeout 20m -v -verbose -profile CLOUDFLAREAPI
This is optional.
Edit README.md:
Add the provider to the bullet list.
Edit .github/workflows/pr_test.yml
Add the name of the provider to the PROVIDERS list.
Edit documentation/providers.md:
Remove the provider from the Requested providers list (near the end of the doc) (if needed).
Edit documentation/SUMMARY.md:
Add the provider to the "Providers" list.
Create documentation/provider/PROVIDERNAME.md:
Use one of the other files in that directory as a base.
Need feedback? Submit a draft PR! It's a great way to get early feedback, ask about fixing a particular integration test, or request feedback.
Some DNS providers have features that others do not. For example some support the SRV record. A provider announces what it can do using the capabilities system.
If a provider doesn't advertise a particular capability, the integration test system skips the appropriate tests. Therefore you might want to initially develop the provider with no particular capabilities advertised and code until all the integration tests work. Then enable capabilities one at a time to finish off the project.
Don't feel obligated to implement everything at once. In fact, we'd prefer a few small PRs than one big one. Focus on getting the basic provider working well before adding these extras.
Operational features have names like providers.CanUseSRV andproviders.CanUseAlias. The list of optional "capabilities" are
in the file dnscontrol/providers/providers.go (look for CanUseAlias).
Capabilities are processed early by DNSControl. For example if a
provider doesn't support SRV records, DNSControl will error out
when parsing dnscontrol.js rather than waiting until the API fails
at the very end.
Enable optional capabilities in the nameProvider.go file and run
the integration tests to see what works and what doesn't. Fix any
bugs and repeat, repeat, repeat until you have all the capabilities
you want to implement.
FYI: If a provider's capabilities changes, run go generate to update
the documentation.
golint is deprecated and frozen but it is still useful as it does a few checks that haven't been
re-implemented in staticcheck.
However golink fails on any file that uses generics, so
be prepared to ignore errors about expected '(', found '[' (and 1 more errors)
In the repo root, open .goreleaser.yml and add the provider to Provider-specific changes regexp.
pr_test.ymlThis assures that in the future it will be easy to test this provider using GitHub Actions.
Edit .github/workflows/pr_test.yml
Add the name of the provider to the PROVIDERS list.
Please keep this list sorted alphabetically.
The entry looks something like:
Add your providers _DOMAIN env variable:
Add it to the env section of integration-tests.
Please keep this list sorted alphabetically.
To find this section, search for PROVIDER SECRET LIST.
For example, the entry for BIND looks like:
Add your providers other ENV variables:
Every provider requires different variables set to perform the integration tests. The list of such variables is in integrationTest/profiles.json.
You've already added *_DOMAIN to pr_test.yml. Now we're going to add the remaining ones.
To find this section, search for PROVIDER SECRET LIST.
For example, the entry for CLOUDFLAREAPI looks like this:
These are the things we'll be checking when you submit the PR. Please try to complete all or as many of these as possible.
Run go generate ./... to make sure all generated files are fresh.
Make sure the following files were created and/or updated:
OWNERS
README.md
.github/workflows/pr_test.yml (The PROVIDERS list)
.goreleaser.yml (Search for Provider-specific changes)
documentation/SUMMARY.md
documentation/providers.md (the autogenerated table + the second one; make sure it is removed from the requested list)
documentation/provider/PROVIDERNAME.md
integrationTest/profiles.json
providers/_all/all.go
Review the code for style issues, remove debug statements, make sure all exported functions have a comment, and generally tighten up the code.
Post the results as a comment to your PR.
At this point you can submit a PR.
The PR should include the sentence: "Please create the GitHub label 'provider-PROVIDERNAME'" (change PROVIDERNAME to the name of your provider.) This is
Actually you can submit the PR earlier if you just want feedback, or have questions. However if you haven't submitted a PR by now, this is the time to do it.
Close any related GitHub issues.
Edit. Add the provider list so DNSControl knows it exists.
Implement all the calls in the.
Implement all the calls in the.
Edit :
If a test will always fail because the provider doesn't support the feature, you can opt out of the test. Look at func makeTests() in for more details.
There is a potential bug in how TXT records are handled. Sadly we haven't found an automated way to test for this bug. The manual steps are here in
Add the new provider to the section.
Run go vet and and clean up any errors found.
Please use go vet from the .
How to install and run :
See for tips about managing modules and checking for outdated dependencies.
Verify you're using the most recent version of anything you import. (See )
Re-run the one last time.
Re-read the bullet list. By submitting a provider you agree to maintain it, respond to bugs, periodically re-run the integration test to verify nothing has broken, and if we don't hear from you for 2 months we may disable the provider.
Would you like your provider to be tested automatically as part of every PR? Sure you would! Follow the instructions in