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Google Cloud DNS

Google Cloud DNS is a high-performance, resilient, global DNS service that provides a cost-effective way to make your applications and services available to your users. This programmable, authoritative DNS service can be used to easily publish and manage DNS records using the same infrastructure relied upon by Google. To learn more, read What is Google Cloud DNS?.

The goal of google-cloud is to provide an API that is comfortable to Rubyists. Your authentication credentials are detected automatically in Google Cloud Platform (GCP), including Google Compute Engine (GCE), Google Kubernetes Engine (GKE), Google App Engine (GAE), Google Cloud Functions (GCF) and Cloud Run. In other environments you can configure authentication easily, either directly in your code or via environment variables. Read more about the options for connecting in the Authentication Guide.

Creating Zones

To get started with Google Cloud DNS, use your DNS Project to create a new Zone. The second argument to Google::Cloud::Dns::Project#create_zone must be a unique domain name for which you can verify ownership. Substitute a domain name of your own (ending with a dot to signify that it is fully qualified) as you follow along with these examples.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.create_zone "example-com", "example.com."
puts zone.id # unique identifier defined by the server

For more information, see Managing Zones.

Listing Zones

You can retrieve all the zones in your project.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zones = dns.zones
zones.each do |zone|
  puts "#{zone.name} - #{zone.dns}"
end

You can also retrieve a single zone by either name or id.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"

Listing Records

When you create a zone, the Cloud DNS service automatically creates two Record instances for it, providing configuration for Cloud DNS nameservers. Let's take a look at these records.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
records = zone.records
records.count #=> 2
records.map &:type #=> ["NS", "SOA"]
zone.records.first.data.count #=> 4
zone.records.first.data #=> ["ns-cloud-d1.googledomains.com.", ...]

Note that Google::Cloud::Dns::Record#data returns an array. The Cloud DNS service only allows the zone to have one Record instance for each name and type combination. It supports multiple "resource records" (in this case, the four nameserver addresses) via this data collection.

Managing Records

You can easily add your own records to the zone. Each call to Google::Cloud::Dns::Zone#add results in a new Cloud DNS Change instance.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
change = zone.add "www", "A", 86400, ["1.2.3.4"]
change.additions.map &:type #=> ["A", "SOA"]
change.deletions.map &:type #=> ["SOA"]

Whenever you change the set of records belonging to a zone, the zone's start of authority (SOA) record should be updated with a higher serial number. The google-cloud library automates this update for you, deleting the old SOA record and adding an updated one, as shown in the example above. You can disable or modify this behavior, of course. See Google::Cloud::Dns::Zone#update for details.

You can retrieve records by name and type. The name argument can be a subdomain (e.g., www) fragment for convenience, but notice that the retrieved record's domain name is always fully-qualified.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
records = zone.records "www", "A"
records.first.name #=> "www.example.com."

You can use Google::Cloud::Dns::Zone#replace to update the ttl and data for a record.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
change = zone.replace "www", "A", 86400, ["5.6.7.8"]

Or, you can use Google::Cloud::Dns::Zone#modify to update just the ttl or data, without the risk of inadvertently changing values that you wish to leave unchanged.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
change = zone.modify "www", "A" do |r|
  r.ttl = 3600 # change only the TTL
end

You can also delete records by name and type.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
change = zone.remove "www", "A"
record = change.deletions.first

The best way to add, remove, and update multiple records in a single transaction is to call Google::Cloud::Dns::Zone#update with a block. See Google::Cloud::Dns::Zone::Transaction.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
change = zone.update do |tx|
  tx.add     "www", "A",  86400, "1.2.3.4"
  tx.remove  "example.com.", "TXT"
  tx.replace "example.com.", "MX", 86400, ["10 mail1.example.com.",
                                           "20 mail2.example.com."]
  tx.modify "www.example.com.", "CNAME" do |r|
    r.ttl = 86400 # only change the TTL
  end
end

Finally, you can add and delete records by reference, using Google::Cloud::Dns::Zone#update.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
to_add = zone.record "www", "AAAA", 86400, ["2607:f8b0:400a:801::1005"]
to_delete = zone.records "www", "A"
change = zone.update to_add, to_delete

Listing Changes

Because the transactions you execute against your zone do not always complete immediately, you can retrieve and inspect changes.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
changes = zone.changes
changes.each do |change|
  puts "#{change.id} - #{change.started_at} - #{change.status}"
end

Importing and exporting zone files

You can import from a zone file. Because the Cloud DNS service only allows the zone to have one Record instance for each name and type combination, lines may be merged as needed into records with multiple data values.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"
change = zone.import "path/to/db.example.com"

You can also export to a zone file.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new
zone = dns.zone "example-com"

zone.export "path/to/db.example.com"

Configuring retries and timeout

You can configure how many times API requests may be automatically retried. When an API request fails, the response will be inspected to see if the request meets criteria indicating that it may succeed on retry, such as 500 and 503 status codes or a specific internal error code such as rateLimitExceeded. If it meets the criteria, the request will be retried after a delay. If another error occurs, the delay will be increased before a subsequent attempt, until the retries limit is reached.

You can also set the request timeout value in seconds.

require "google/cloud/dns"

dns = Google::Cloud::Dns.new retries: 10, timeout: 120

Additional information

Google Cloud DNS can be configured to use logging. To learn more, see the Logging guide.