ref(dnsupdate): move under tools

Integrate properly the tool `dnsupdate` with flake.nix, by adding a
default.nix inside its directory.

Having all the tools under a directory named `tools` is easier to reason
about. I don't need a go.mod at the top level directory either, each
tool will have its own.

3 files changed, 0 insertions, 222 deletions

diff --git a/cmd/dnsupdate/README.org b/cmd/dnsupdate/README.org
deleted file mode 100644
index a80e407..0000000
--- a/cmd/dnsupdate/README.org
+++ /dev/null
@@ -1,7 +0,0 @@
-#+TITLE: dnsupdate
-
-Utility to update the managed zone for =fcuny.xyz= in Google Cloud.
-
-I use the domain =fcuny.xyz= to run a number of services on an IP provided by Tailscale. I don't want these domains to be visible on the web, but I also want to have a valid HTTPS certificate for them. By having a proper DNS I can use ACME to get the certificates, without making them available.
-
-Instead of updating the subdomains through the [[https://console.cloud.google.com/net-services/dns/zones/fcuny-xyz/details?project=fcuny-homelab][console]], I can now run this program.
diff --git a/cmd/dnsupdate/main.go b/cmd/dnsupdate/main.go
deleted file mode 100644
index 6748ee9..0000000
--- a/cmd/dnsupdate/main.go
+++ /dev/null
@@ -1,126 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"log"
-
-	dns "google.golang.org/api/dns/v1"
-)
-
-const (
-	GCP_PROJECT_NAME = "fcuny-homelab"
-	GCP_MANAGED_ZONE = "fcuny-xyz"
-	TS_DEVICE_NAME   = "tahoe"
-	TTL              = 300
-)
-
-var desiredRecords = []string{
-	"bt",
-	"cs",
-	"dash",
-	"drone",
-	"music",
-	"unifi",
-}
-
-func main() {
-	ctx := context.Background()
-
-	// we only care about IPv4 for now
-	tsIpV4Addresses, _, err := getTsIpsDevice(ctx, TS_DEVICE_NAME)
-	if err != nil {
-		log.Fatalf("failed to get the IP addresses for %s: %v", TS_DEVICE_NAME, err)
-	}
-
-	svc, err := dns.NewService(ctx)
-	if err != nil {
-		log.Fatalf("failed to create the client for Google Cloud DNS: %v", err)
-	}
-
-	zone, err := svc.ManagedZones.Get(GCP_PROJECT_NAME, GCP_MANAGED_ZONE).Context(ctx).Do()
-	if err != nil {
-		log.Fatalf("failed to get information about the managed zone %s: %+v", GCP_MANAGED_ZONE, err)
-	}
-
-	recordSets, err := svc.ResourceRecordSets.List(GCP_PROJECT_NAME, GCP_MANAGED_ZONE).Context(ctx).Do()
-	if err != nil {
-		log.Fatalf("failed to get the list of records: %+v", err)
-	}
-
-	var (
-		existingRecordSets = []*dns.ResourceRecordSet{}
-		recordSetsToAdd    = []*dns.ResourceRecordSet{}
-		recordSetsToDelete = []*dns.ResourceRecordSet{}
-	)
-
-	for _, record := range recordSets.Rrsets {
-		if record.Type == "A" {
-			existingRecordSets = append(existingRecordSets, record)
-		}
-	}
-
-	// first pass: create what's missing
-	for _, subdomain := range desiredRecords {
-		found := false
-		subdomain = fmt.Sprintf("%s.%s", subdomain, zone.DnsName)
-		for _, r := range existingRecordSets {
-			if subdomain == r.Name && r.Type == "A" {
-				// check that the IP addresses are correct
-				ipsFound := 0
-				for _, rr := range r.Rrdatas {
-					for _, ip := range tsIpV4Addresses {
-						if rr == ip {
-							ipsFound += 1
-							continue
-						}
-					}
-				}
-				// while we found the subdomain with the correct type,
-				// we also need to make sure the list of IPs is
-				// correct. If they are not, we delete the record and
-				// add it again with the correct values.
-				if ipsFound == len(tsIpV4Addresses) {
-					found = true
-					continue
-				} else {
-					log.Printf("will delete %s (incorrect IPv4 addresses)\n", subdomain)
-					recordSetsToDelete = append(recordSetsToDelete, r)
-				}
-			}
-		}
-		if !found {
-			log.Printf("will add %s\n", subdomain)
-			r := &dns.ResourceRecordSet{
-				Name:    subdomain,
-				Type:    "A",
-				Ttl:     TTL,
-				Rrdatas: tsIpV4Addresses,
-			}
-			recordSetsToAdd = append(recordSetsToAdd, r)
-		}
-	}
-
-	// second pass: delete what's not needed
-	for _, r := range existingRecordSets {
-		found := false
-		for _, subdomain := range desiredRecords {
-			subdomain = fmt.Sprintf("%s.%s", subdomain, zone.DnsName)
-			if subdomain == r.Name && r.Type == "A" {
-				found = true
-				continue
-			}
-		}
-		if !found {
-			log.Printf("will delete %s\n", r.Name)
-			recordSetsToDelete = append(recordSetsToDelete, r)
-		}
-	}
-
-	if len(recordSetsToAdd) > 0 || len(recordSetsToDelete) > 0 {
-		change := &dns.Change{Additions: recordSetsToAdd, Deletions: recordSetsToDelete}
-		if _, err = svc.Changes.Create(GCP_PROJECT_NAME, GCP_MANAGED_ZONE, change).Context(ctx).Do(); err != nil {
-			log.Fatalf("failed to apply the change: %+v", err)
-		}
-	}
-}
diff --git a/cmd/dnsupdate/ts.go b/cmd/dnsupdate/ts.go
deleted file mode 100644
index 4d3ebb3..0000000
--- a/cmd/dnsupdate/ts.go
+++ /dev/null
@@ -1,89 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net/http"
-	"os"
-
-	"inet.af/netaddr"
-)
-
-type device struct {
-	Hostname  string   `json:"hostname"`
-	ID        string   `json:"id"`
-	Addresses []string `json:"addresses"`
-}
-
-const (
-	TS_NAME       = "franck.cuny@gmail.com"
-	TS_API_DOMAIN = "api.tailscale.com"
-)
-
-func getTsDevice(ctx context.Context, deviceName string) (*device, error) {
-	apiKey, found := os.LookupEnv("TS_API_KEY")
-	if !found {
-		return nil, errors.New("the environment variable TS_API_KEY is not set")
-	}
-
-	url := fmt.Sprintf("https://%s/api/v2/tailnet/%s/devices", TS_API_DOMAIN, TS_NAME)
-	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
-	if err != nil {
-		return nil, err
-	}
-
-	req.SetBasicAuth(apiKey, "")
-	resp, err := http.DefaultClient.Do(req)
-	if err != nil {
-		return nil, err
-	}
-
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("non-ok status code %d returned from tailscale api: %s", resp.StatusCode, resp.Status)
-	}
-	var buf struct {
-		Devices []device `json:"devices"`
-	}
-	if err := json.NewDecoder(resp.Body).Decode(&buf); err != nil {
-		return nil, err
-	}
-
-	for _, d := range buf.Devices {
-		if d.Hostname == deviceName {
-			return &d, nil
-		}
-	}
-	return nil, fmt.Errorf("could not find the tailscale device named %s", deviceName)
-}
-
-// Get the Tailscale IPv4 and IPv6 addresses associated with the given device.
-func getTsIpsDevice(ctx context.Context, device string) ([]string, []string, error) {
-	ts_device, err := getTsDevice(ctx, device)
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to get Tailscale device information: %v", err)
-	}
-
-	var (
-		tsIpV4Addresses = []string{}
-		tsIpV6Addresses = []string{}
-	)
-	for _, ipString := range ts_device.Addresses {
-		// we convert the string to a netaddr.IP so we can check if
-		// it's an IP v4 or v6. We need to know what's the version in
-		// order to use it properly when creating/updating the
-		// record. Then we convert it back as a string, since this is
-		// what the DNS API expect.
-		ip := netaddr.MustParseIP(ipString)
-		if ip.Is4() {
-			tsIpV4Addresses = append(tsIpV4Addresses, ip.String())
-		} else {
-			tsIpV6Addresses = append(tsIpV6Addresses, ip.String())
-		}
-	}
-
-	return tsIpV4Addresses, tsIpV6Addresses, nil
-}