# get-zones

DNSControl has a stand-alone utility that will contact a provider,
download the records of one or more zones, and output them to a file
in a variety of formats.

`get-zones` relies on command line parameters and `creds.json`
exclusively.  It does not use `dnsconfig.js`. This is to assist
bootstrapping a new system.

## Use case 1: Bootstrapping a new system

If you are moving a DNS zone from a provider to DNSControl, this
command will do most of the work for you by downloading the records
and writing them out in `dnsconfig.js` format. It is intended to be
"a decent first draft", only requiring minimal editing.

Use `--format=djs` or `--format=js` (djs is recommended; djs format is a
comma-leading formatting style for lists, sometimes also called Haskell style).

Minor editing is required. Not all record formats are supported.
SOA records are commented out, since most providers do not support it.
BIND supports it, but requires the data to be entered as meta data.

The `NAMESERVER()` command is generated commented out. This is usually
not needed as DNSControl can get more accurate information via the
API. Remove the comments only to override the DNS service provider.

## Use case 2: Generating BIND ZONE files

The `--format=zone` generates BIND-style zonefiles. Pseudo records not
supported by BIND are generated as comments.

This format is useful when moving zonedata between providers, since
the format is relatively universal.

This format is also useful for generating backups of DNS zones. Unlike
making a backup of the `dnsconfig.js`, this is the raw records, which
may be useful.

## Use case 3: TAB separated values

The goal of `--format=tsv` is to provide a high-fidelity format that is easy
enough to parse with `awk`.

## Use case 4: List zones

If a provider supports it, `--format=nameonly` lists the names of the
zones at the provider.


## Syntax

```shell
dnscontrol get-zones [command options] credkey provider zone [...]

--creds value   Provider credentials JSON file (default: "creds.json")
--format value  Output format: js djs zone tsv nameonly (default: "zone")
--out value     Instead of stdout, write to this file
--ttl value     Default TTL (0 picks the zone's most common TTL) (default: 0)

ARGUMENTS:
credkey:  The name used in creds.json (first parameter to NewDnsProvider() in dnsconfig.js)
provider: The name of the provider (second parameter to NewDnsProvider() in dnsconfig.js)
zone:     One or more zones (domains) to download; or "all".
```

As of [v3.16](../release/v316.md), `provider` can be `-` to indicate that the provider name is listed in `creds.json` in the `TYPE` field. Doing this will be backwards compatible with an (otherwise) breaking change due in v4.0.

As of v4.0 (BREAKING CHANGE), you must not specify `provider`.  That value is found in the `TYPE` field of the credkey's `creds.json` file.  For backwards compatibility, if the first `zone` is `-`, it will be skipped.

```shell
FORMATS:
--format=js        dnsconfig.js format (not perfect, just a decent first draft)
--format=djs       js with disco commas (leading commas)
--format=zone      BIND zonefile format
--format=tsv       TAB separated value (useful for AWK)
--format=nameonly  Just print the zone names

The columns in `--format=tsv` are:

    FQDN (the label with the domain)
    ShortName (just the label, "@" if it is the naked domain)
    TTL
    Record Type (A, AAAA, CNAME, etc.)
    Target and arguments (quoted like in a zonefile)
    Either empty or a comma-separated list of properties like "cloudflare_proxy=true"

The `--ttl` flag only applies to zone/js/djs formats.
```

## Examples

```shell
dnscontrol get-zones myr53 ROUTE53 example.com
dnscontrol get-zones gmain GANDI_V5 example.comn other.com
dnscontrol get-zones cfmain CLOUDFLAREAPI all
dnscontrol get-zones --format=tsv bind BIND example.com
dnscontrol get-zones --format=djs --out=draft.js glcoud GCLOUD example.com
```

As of [v3.16](../release/v316.md):

```shell
# NOTE: When "-" appears as the 2nd argument, it is assumed that the
# creds.json entry has a field TYPE with the provider's type name.
dnscontrol get-zones gmain GANDI_V5 example.comn other.com
dnscontrol get-zones gmain - example.comn other.com
dnscontrol get-zones cfmain CLOUDFLAREAPI all
dnscontrol get-zones cfmain - all
dnscontrol get-zones --format=tsv bind BIND example.com
dnscontrol get-zones --format=tsv bind - example.com
dnscontrol get-zones --format=djs --out=draft.js glcoud GCLOUD example.com
dnscontrol get-zones --format=djs --out=draft.js glcoud - example.com
```

As of v4.0:

```shell
dnscontrol get-zones gmain example.comn other.com
dnscontrol get-zones cfmain all
dnscontrol get-zones --format=tsv bind example.com
dnscontrol get-zones --format=djs --out=draft.js glcoud example.com
```

For backwards compatibility, these are valid until at least v5.0

```shell
dnscontrol get-zones gmain - example.comn other.com
dnscontrol get-zones cfmain - all
dnscontrol get-zones --format=tsv bind - example.com
dnscontrol get-zones --format=djs --out=draft.js glcoud - example.com
```

Read a zonefile, generate a JS file, then use the JS file to see how
different it is from the zonefile:

```shell
dnscontrol get-zone --format=djs -out=foo.djs bind - example.com
dnscontrol preview --config foo.js
```

# Developer Notes

This command is not implemented for all providers.

To add this to a provider:

**Step 1. Document the feature**

In the `*provider.go` file, change the setting to implemented.

{% code title="provider.go" %}
```diff
-providers.CanGetZones: providers.Unimplemented(),
+providers.CanGetZones: providers.Can(),
```
{% endcode %}

**Step 2. Update the docs**

```shell
go generate
```

**Step 3. Implement the `GetZoneRecords` function**

Find the `GetZoneRecords` function in the `*Provider.go` file.

It currently returns `fmt.Errorf("not implemented")`.

Instead, it should gather the records from the provider
and return them as a list of RecordConfig structs.

The code to do that already exists in `GetDomainCorrections`.
You should extract it into its own function (`GetZoneRecords`), rather
than having it be buried in the middle of `GetDomainCorrections`.
`GetDomainCorrections` should call `GetZoneRecords`.

Once that is done the `get-zone` subcommand should work.

**Step 4. Optionally implement the `ListZones` function**

If the `ListZones` function is implemented, the "all" special case
will be activated.  In this case, listing a single zone named `all`
will query the provider for the list of zones.

(Technically what is happening is by implementing the `ListZones`
function, you are completing the `ZoneLister` interface for that
provider.)

Implementing the `ListZones` function also activates the `check-creds`
subcommand for that provider. Please add to the provider documentation
a list of error messages that people might see if the credentials are
invalid.  See `documentation/provider/gcloud.md` for examples.
