Don't use globals for registering platforms configuration structs

This commit moves platforms registration logic from using globals to
single function in cli/cmd/cluster package, as this is the only user of
old GetPlatforms() function.

For platform unit tests, NewConfig() function exported by each platform
package should be used instead.

Refs #992

Signed-off-by: Mateusz Gozdek <mateusz@kinvolk.io>

cli/cmd/cluster/utils.go

@@ -27,6 +27,11 @@ import (
 	"github.com/kinvolk/lokomotive/pkg/backend"
 	"github.com/kinvolk/lokomotive/pkg/config"
 	"github.com/kinvolk/lokomotive/pkg/platform"
+	"github.com/kinvolk/lokomotive/pkg/platform/aks"
+	"github.com/kinvolk/lokomotive/pkg/platform/aws"
+	"github.com/kinvolk/lokomotive/pkg/platform/baremetal"
+	"github.com/kinvolk/lokomotive/pkg/platform/packet"
+	"github.com/kinvolk/lokomotive/pkg/platform/tinkerbell"
 )
 
 const (
@@ -54,6 +59,22 @@ func getConfiguredBackend(lokoConfig *config.Config) (backend.Backend, hcl.Diagn
 	return backend, backend.LoadConfig(&lokoConfig.RootConfig.Backend.Config, lokoConfig.EvalContext)
 }
 
+func getPlatform(name string) (platform.Platform, error) {
+	platforms := map[string]platform.Platform{
+		aks.Name:        aks.NewConfig(),
+		aws.Name:        aws.NewConfig(),
+		packet.Name:     packet.NewConfig(),
+		baremetal.Name:  baremetal.NewConfig(),
+		tinkerbell.Name: tinkerbell.NewConfig(),
+	}
+
+	if p, ok := platforms[name]; ok {
+		return p, nil
+	}
+
+	return nil, fmt.Errorf("platform %q not found", name)
+}
+
 // getConfiguredPlatform loads a platform from the given configuration file.
 func getConfiguredPlatform(lokoConfig *config.Config, require bool) (platform.Platform, hcl.Diagnostics) {
 	if lokoConfig.RootConfig.Cluster == nil && !require {
@@ -70,7 +91,7 @@ func getConfiguredPlatform(lokoConfig *config.Config, require bool) (platform.Pl
 		}
 	}
 
-	platform, err := platform.GetPlatform(lokoConfig.RootConfig.Cluster.Name)
+	platform, err := getPlatform(lokoConfig.RootConfig.Cluster.Name)
 	if err != nil {
 		diag := &hcl.Diagnostic{
 			Severity: hcl.DiagError,

pkg/platform/aks/aks.go

@@ -86,11 +86,6 @@ const (
 	kubernetesVersion = "1.18.10"
 )
 
-// init registers AKS as a platform.
-func init() { //nolint:gochecknoinits
-	platform.Register(Name, NewConfig())
-}
-
 // NewConfig returns new AKS platform configuration with default values set.
 //
 //nolint:golint

pkg/platform/aws/aws.go

@@ -93,11 +93,6 @@ const (
 	Name = "aws"
 )
 
-// init registers aws as a platform
-func init() {
-	platform.Register(Name, NewConfig())
-}
-
 func (c *config) LoadConfig(configBody *hcl.Body, evalContext *hcl.EvalContext) hcl.Diagnostics {
 	if configBody == nil {
 		return hcl.Diagnostics{}

pkg/platform/baremetal/baremetal.go

@@ -65,11 +65,6 @@ const (
 	Name = "bare-metal"
 )
 
-// init registers bare-metal as a platform
-func init() {
-	platform.Register(Name, NewConfig())
-}
-
 func (c *config) LoadConfig(configBody *hcl.Body, evalContext *hcl.EvalContext) hcl.Diagnostics {
 	if configBody == nil {
 		return hcl.Diagnostics{}

pkg/platform/packet/packet.go

@@ -110,11 +110,6 @@ const (
 	Name = "packet"
 )
 
-// init registers packet as a platform
-func init() {
-	platform.Register(Name, NewConfig())
-}
-
 func (c *config) LoadConfig(configBody *hcl.Body, evalContext *hcl.EvalContext) hcl.Diagnostics {
 	if configBody == nil {
 		return hcl.Diagnostics{}

pkg/platform/platform.go

@@ -118,31 +118,6 @@ type Meta struct {
 	ControlplaneCharts []helm.LokomotiveChart
 }
 
-// platforms is a collection where all platforms gets automatically registered
-var platforms map[string]Platform
-
-// initialize package's global variable when package is imported
-func init() {
-	platforms = make(map[string]Platform)
-}
-
-// Register adds platform into internal map
-func Register(name string, p Platform) {
-	if _, exists := platforms[name]; exists {
-		panic(fmt.Sprintf("platform with name %q registered already", name))
-	}
-	platforms[name] = p
-}
-
-// GetPlatform returns platform based on the name
-func GetPlatform(name string) (Platform, error) {
-	platform, exists := platforms[name]
-	if !exists {
-		return nil, fmt.Errorf("no platform with name %q found", name)
-	}
-	return platform, nil
-}
-
 // AppendVersionTag appends the lokoctl-version tag to a given tags map.
 func AppendVersionTag(tags *map[string]string) {
 	if tags == nil {

pkg/platform/tinkerbell/tinkerbell.go

@@ -94,11 +94,6 @@ func (w *WorkerPool) Name() string {
 	return w.PoolName
 }
 
-// init registers tinkerbell as a platform.
-func init() { //nolint:gochecknoinits
-	platform.Register(Name, NewConfig())
-}
-
 // LoadConfig loads platform configuration using given HCL structs.
 func (c *Config) LoadConfig(configBody *hcl.Body, evalContext *hcl.EvalContext) hcl.Diagnostics {
 	if configBody == nil {