tags: rudimentary support for tagging and filtering

data/eval-machines.nix

@@ -62,7 +62,7 @@ rec {
 
     machines =
       flip mapAttrs nodes (n: v': let v = scrubOptionValue v'; in
-        { inherit (v.config.deployment) targetHost targetUser secrets healthChecks buildOnly substituteOnDestination;
+        { inherit (v.config.deployment) targetHost targetUser secrets healthChecks buildOnly substituteOnDestination tags;
           name = n;
           nixosRelease = v.config.system.nixos.release or (removeSuffix v.config.system.nixos.version.suffix v.config.system.nixos.version);
           nixConfig = mapAttrs

data/options.nix

@@ -221,6 +221,14 @@ in
       '';
       default = {};
     };
+
+    tags = mkOption {
+      type = listOf str;
+      default = [];
+      description = ''
+        Host tags.
+      '';
+    };
   };
 
   # Creates a txt-file that lists all system healthcheck commands

filter/filter.go

@@ -36,3 +36,18 @@ func FilterHosts(allHosts []nix.Host, skip int, every int, limit int) (hosts []n
 		return hosts
 	}
 }
+
+func FilterHostsTags(allHosts []nix.Host, selectedTag string) (hosts []nix.Host) {
+	if selectedTag == "" {
+		return allHosts
+	}
+	for _, host := range allHosts {
+		for _, tag := range host.GetTags() {
+			if tag == selectedTag {
+				hosts = append(hosts, host)
+			}
+		}
+	}
+
+	return
+}

morph.go

@@ -25,6 +25,7 @@ var (
 	app                 = kingpin.New("morph", "NixOS host manager").Version(version)
 	dryRun              = app.Flag("dry-run", "Don't do anything, just eval and print changes").Default("False").Bool()
 	selectGlob          string
+	selectTag           string
 	selectEvery         int
 	selectSkip          int
 	selectLimit         int
@@ -78,6 +79,9 @@ func selectorFlags(cmd *kingpin.CmdClause) {
 	cmd.Flag("on", "Glob for selecting servers in the deployment").
 		Default("*").
 		StringVar(&selectGlob)
+	cmd.Flag("tagged", "Select hosts with these tags").
+		Default("").
+		StringVar(&selectTag)
 	cmd.Flag("every", "Select every n hosts").
 		Default("1").
 		IntVar(&selectEvery)
@@ -218,8 +222,6 @@ func setup() {
 	handleError(assetErr)
 }
 
-
-
 func main() {
 
 	clause := kingpin.MustParse(app.Parse(os.Args[1:]))
@@ -507,11 +509,13 @@ func getHosts(deploymentFile string) (hosts []nix.Host, err error) {
 		return hosts, err
 	}
 
-	filteredHosts := filter.FilterHosts(matchingHosts, selectSkip, selectEvery, selectLimit)
+	matchingHosts2 := filter.FilterHostsTags(matchingHosts, selectTag)
+
+	filteredHosts := filter.FilterHosts(matchingHosts2, selectSkip, selectEvery, selectLimit)
 
 	fmt.Fprintf(os.Stderr, "Selected %v/%v hosts (name filter:-%v, limits:-%v):\n", len(filteredHosts), len(allHosts), len(allHosts)-len(matchingHosts), len(matchingHosts)-len(filteredHosts))
 	for index, host := range filteredHosts {
-		fmt.Fprintf(os.Stderr, "\t%3d: %s (secrets: %d, health checks: %d)\n", index, host.Name, len(host.Secrets), len(host.HealthChecks.Cmd)+len(host.HealthChecks.Http))
+		fmt.Fprintf(os.Stderr, "\t%3d: %s (secrets: %d, health checks: %d, tags: %s)\n", index, host.Name, len(host.Secrets), len(host.HealthChecks.Cmd)+len(host.HealthChecks.Http), strings.Join(host.GetTags(), ","))
 	}
 	fmt.Fprintln(os.Stderr)
 

nix/nix.go

@@ -29,6 +29,7 @@ type Host struct {
 	BuildOnly               bool
 	SubstituteOnDestination bool
 	NixConfig               map[string]string
+	Tags                    []string
 }
 
 type NixContext struct {
@@ -58,6 +59,10 @@ func (host *Host) GetHealthChecks() healthchecks.HealthChecks {
 	return host.HealthChecks
 }
 
+func (host *Host) GetTags() []string {
+	return host.Tags
+}
+
 func (host *Host) Reboot(sshContext *ssh.SSHContext) error {
 
 	var (