feat: store presets as YAML rather than Go

.goreleaser.yaml

@@ -38,7 +38,7 @@ snapcrafts:
       must be in the current working directory and named 'concierge.yaml', or the path specified using
       the '-c' flag.
 
-      There are 3 presets available by default: 'machine', 'k8s' and 'dev'.
+      Several presets are available by default to cover common charm development and testing scenarios.
 
       Some aspects of presets and config files can be overridden using flags such as '--juju-channel'.
       Each of the override flags has an environment variable equivalent, such as
@@ -49,6 +49,21 @@ snapcrafts:
       - source: .github/concierge.png
         destination: concierge.png
         mode: 0644
+      - source: presets/crafts.yaml
+        destination: presets/crafts.yaml
+        mode: 0644
+      - source: presets/dev.yaml
+        destination: presets/dev.yaml
+        mode: 0644
+      - source: presets/k8s.yaml
+        destination: presets/k8s.yaml
+        mode: 0644
+      - source: presets/machine.yaml
+        destination: presets/machine.yaml
+        mode: 0644
+      - source: presets/microk8s.yaml
+        destination: presets/microk8s.yaml
+        mode: 0644
 
 checksum:
   name_template: "checksums.txt"

cmd/prepare.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/canonical/concierge/internal/concierge"
 	"github.com/canonical/concierge/internal/config"
@@ -10,23 +11,26 @@ import (
 
 // prepareCmd constructs the `prepare` subcommand
 func prepareCmd() *cobra.Command {
+	presetNames := config.ValidPresets()
+	presetList := strings.Join(presetNames, ", ")
+
 	cmd := &cobra.Command{
 		Use:   "prepare",
 		Short: "Provision the machine according to the configuration.",
-		Long: `Provision the machine according to the configuration.
+		Long: fmt.Sprintf(`Provision the machine according to the configuration.
 
 Configuration is by flags/environment variables, or by configuration file. The configuration file
 must be in the current working directory and named 'concierge.yaml', or the path specified using
 the '-c' flag.
 
-There are 3 presets available by default: 'machine', 'k8s' and 'dev'.
+Available presets: %s.
 
 Some aspects of presets and config files can be overridden using flags such as '--juju-channel'.
-Each of the override flags has an environment variable equivalent, 
+Each of the override flags has an environment variable equivalent,
 such as 'CONCIERGE_JUJU_CHANNEL'.
 
 More information at https://github.com/canonical/concierge.
-`,
+`, presetList),
 		SilenceErrors: true,
 		SilenceUsage:  true,
 		PreRunE: func(cmd *cobra.Command, args []string) error {
@@ -60,7 +64,7 @@ More information at https://github.com/canonical/concierge.
 
 	flags := cmd.Flags()
 	flags.StringP("config", "c", "", "path to a specific config file to use")
-	flags.StringP("preset", "p", "", "config preset to use (k8s | machine | dev)")
+	flags.StringP("preset", "p", "", "config preset to use ("+strings.Join(presetNames, " | ")+")")
 	flags.Bool("disable-juju", false, "disable the installation and bootstrap of juju")
 	flags.String("juju-channel", "", "override the snap channel for juju")
 	flags.String("k8s-channel", "", "override snap channel for the k8s snap")

internal/config/presets.go

@@ -1,162 +1,59 @@
 package config
 
-import "fmt"
-
-// Preset returns a configuration preset by name.
-func Preset(preset string) (*Config, error) {
-	switch preset {
-	case "k8s":
-		return k8sPreset, nil
-	case "microk8s":
-		return microk8sPreset, nil
-	case "machine":
-		return machinePreset, nil
-	case "dev":
-		return devPreset, nil
-	case "crafts":
-		return craftsPreset, nil
-	default:
-		return nil, fmt.Errorf("unknown preset '%s'", preset)
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io/fs"
+	"sort"
+	"strings"
+
+	"github.com/canonical/concierge/presets"
+	"github.com/spf13/viper"
+)
+
+// ValidPresets returns the sorted list of available preset names.
+func ValidPresets() []string {
+	entries, err := presets.FS.ReadDir(".")
+	if err != nil {
+		return nil
 	}
-}
-
-// defaultJujuConfig is the default Juju config for all presets.
-var defaultJujuConfig jujuConfig = jujuConfig{
-	Disable: false,
-	ModelDefaults: map[string]string{
-		"test-mode":                 "true",
-		"automatically-retry-hooks": "false",
-	},
-}
-
-// defaultPackages is the set of packages installed for all presets.
-var defaultPackages []string = []string{
-	"gnome-keyring",
-	"python3-pip",
-	"python3-venv",
-}
-
-// defaultSnaps is the set of snaps installed for all presets.
-var defaultSnaps map[string]SnapConfig = map[string]SnapConfig{
-	"charmcraft": {Channel: "latest/stable"},
-	"jq":         {Channel: "latest/stable"},
-	"yq":         {Channel: "latest/stable"},
-}
-
-// defaultLXDConfig is the standard LXD config used throughout presets.
-var defaultLXDConfig lxdConfig = lxdConfig{
-	Enable:    true,
-	Bootstrap: true,
-}
 
-// defaultMicroK8sConfig is the standard MicroK8s config used throughout presets.
-var defaultMicroK8sConfig microk8sConfig = microk8sConfig{
-	Enable:    true,
-	Bootstrap: true,
-	Addons: []string{
-		"hostpath-storage",
-		"dns",
-		"rbac",
-		"metallb:10.64.140.43-10.64.140.49",
-	},
-}
-
-// defaultK8sConfig is the standard K8s config used throughout presets.
-var defaultK8sConfig k8sConfig = k8sConfig{
-	Enable:               true,
-	Bootstrap:            true,
-	BootstrapConstraints: map[string]string{"root-disk": "2G"},
-	Features: map[string]map[string]string{
-		"load-balancer": {
-			"l2-mode": "true",
-			"cidrs":   "10.43.45.0/28",
-		},
-		"local-storage": {},
-		"network":       {},
-	},
-}
-
-// machinePreset is a configuration preset designed to be used when testing
-// machine charms.
-var machinePreset *Config = &Config{
-	Juju: defaultJujuConfig,
-	Providers: providerConfig{
-		LXD: defaultLXDConfig,
-	},
-	Host: hostConfig{
-		Packages: defaultPackages,
-		Snaps: MergeMaps(defaultSnaps, map[string]SnapConfig{
-			"snapcraft": {Channel: "latest/stable"},
-		}),
-	},
+	var names []string
+	for _, e := range entries {
+		if !e.IsDir() && strings.HasSuffix(e.Name(), ".yaml") {
+			names = append(names, strings.TrimSuffix(e.Name(), ".yaml"))
+		}
+	}
+	sort.Strings(names)
+	return names
 }
 
-// k8sPreset is a configuration preset designed to be used when testing
-// k8s charms.
-var k8sPreset *Config = &Config{
-	Juju: defaultJujuConfig,
-	Providers: providerConfig{
-		// Enable LXD so charms can be built, but don't bootstrap onto it.
-		LXD: lxdConfig{Enable: true},
-		K8s: defaultK8sConfig,
-	},
-	Host: hostConfig{
-		Packages: defaultPackages,
-		Snaps: MergeMaps(defaultSnaps, map[string]SnapConfig{
-			"rockcraft": {Channel: "latest/stable"},
-		}),
-	},
+// Preset returns a configuration preset by name.
+func Preset(preset string) (*Config, error) {
+	filename := preset + ".yaml"
+	data, err := presets.FS.ReadFile(filename)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			return nil, fmt.Errorf("unknown preset '%s'", preset)
+		}
+		return nil, fmt.Errorf("failed to read preset '%s': %w", preset, err)
+	}
+	return loadPreset(data)
 }
 
-// microk8sPreset is a configuration preset designed to be used when testing
-// k8s charms.
-var microk8sPreset *Config = &Config{
-	Juju: defaultJujuConfig,
-	Providers: providerConfig{
-		// Enable LXD so charms can be built, but don't bootstrap onto it.
-		LXD:      lxdConfig{Enable: true},
-		MicroK8s: defaultMicroK8sConfig,
-	},
-	Host: hostConfig{
-		Packages: defaultPackages,
-		Snaps: MergeMaps(defaultSnaps, map[string]SnapConfig{
-			"rockcraft": {Channel: "latest/stable"},
-		}),
-	},
-}
+// loadPreset parses YAML data into a Config using a fresh Viper instance.
+func loadPreset(data []byte) (*Config, error) {
+	v := viper.New()
+	v.SetConfigType("yaml")
 
-// devPreset combines both the LXD and K8s presets, designed to be used by
-// developers when iterating on charms.
-var devPreset *Config = &Config{
-	Juju: defaultJujuConfig,
-	Providers: providerConfig{
-		LXD: defaultLXDConfig,
-		K8s: defaultK8sConfig,
-	},
-	Host: hostConfig{
-		Packages: defaultPackages,
-		Snaps: MergeMaps(defaultSnaps, map[string]SnapConfig{
-			"rockcraft": {Channel: "latest/stable"},
-			"snapcraft": {Channel: "latest/stable"},
-			"jhack":     {Channel: "latest/stable", Connections: []string{"jhack:dot-local-share-juju"}},
-		}),
-	},
-}
+	if err := v.ReadConfig(bytes.NewReader(data)); err != nil {
+		return nil, fmt.Errorf("failed to parse preset: %w", err)
+	}
 
-// craftsPreset installs each of the crafts, and configures LXD, but disables Juju.
-// Useful for workflows where only artifacts need to be built.
-var craftsPreset *Config = &Config{
-	Juju: jujuConfig{
-		Disable: true,
-	},
-	Providers: providerConfig{
-		LXD: defaultLXDConfig,
-	},
-	Host: hostConfig{
-		Packages: defaultPackages,
-		Snaps: MergeMaps(defaultSnaps, map[string]SnapConfig{
-			"rockcraft": {Channel: "latest/stable"},
-			"snapcraft": {Channel: "latest/stable"},
-		}),
-	},
+	conf := &Config{}
+	if err := v.Unmarshal(conf); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal preset: %w", err)
+	}
+	return conf, nil
 }