dnscontrol/docs/writing-providers.md

layout	title
default	Writing new DNS providers

Writing new DNS providers

Writing a new DNS provider is a relatively straightforward process. You essentially need to implement the providers.DNSServiceProvider interface. 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 here.

Step 1: General advice

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 dicuss them in the Github issue related to the request for this provider. Please let us know what was confusing so we can update this document with advice for future authors (or even better, update this document yourself.)

Step 2: Pick a base provider

Pick a similar provider as your base. Providers basically fall into three general categories:

• zone: The API requires you to upload the entire zone every time. (BIND, GANDI).
• incremental-record: The API lets you add/change/delete individual DNS records. (ACTIVEDIR, CLOUDFLARE, NAMEDOTCOM, GCLOUD, ROUTE53)
• incremental-label: Similar to incremental, but the API requires you to update all the records related to a particular label each time. For example, if a label (www.example.com) has an A and MX record, any change requires replacing all the records for that label.

TODO: Categorize DNSIMPLE, NAMECHEAP

All providers use the "diff" module to detect differences. It takes two zones and returns records that are unchanged, created, deleted, and modified. The incremental providers use the differences to update individual records or recordsets. The zone providers use the information to print a human-readable list of what is being changed, but upload the entire new zone.

Step 3: Create the driver skeleton

Create a directory for the provider called providers/name where name 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 called api.go).

Step 4: Activate the driver

Edit providers/_all/all.go. Add the provider list so DNSControl knows it exists.

Step 5: Implement

Implement all the calls in providers.DNSServiceProvider interface..

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.

Step 6: Unit Test

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:

cd dnscontrol
go test ./...

Step 7: Integration Test

This is the most important kind of testing when adding a new provider. Integration tests use a test account and a real domain.

• Edit integrationTest/providers.json: Add the creds.json info required for this provider.

For example, this will run the tests using BIND:

cd dnscontrol/integrationTest
go test -v -verbose -provider BIND

(BIND is a good place to start since it doesn't require any API keys.)

This will run the tests on Amazon AWS Route53:

export R53_DOMAIN=dnscontroltest-r53.com  # Use a test domain.
export R53_KEY_ID=CHANGE_TO_THE_ID
export R53_KEY='CHANGE_TO_THE_KEY'
go test -v -verbose -provider ROUTE53

Step 5: Update docs

• Edit README.md: Add the provider to the bullet list.
• Edit docs/provider-list.md: Add the provider to the provider list.
• Create docs/_providers/PROVIDERNAME.md: Use one of the other files in that directory as a base.

Step 6: Submit a PR

At this point you can submit a PR.

Actually you can submit the PR even earlier if you just want feedback, input, or have questions. This is just a good stopping place to submit a PR. At a minimum a new provider should pass all the integration tests. Everything else is a bonus.

Step 7: Capabilities

The last step is to add any optional provider capabilities. You can submit these as a separate PR once the main provider is working. 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 and providers.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.

Vendoring Dependencies

If your provider depends on other go packages, then you must vendor them. To do this, use govendor. A command like this is usually suffient:

go get github.com/kardianos/govendor
govendor add +e