config: make ProviderConfigs slice

config/config.go

@@ -13,7 +13,7 @@ import (
 // Config is the configuration that comes from loading a collection
 // of Terraform templates.
 type Config struct {
-	ProviderConfigs map[string]*ProviderConfig
+	ProviderConfigs []*ProviderConfig
 	Resources       []*Resource
 	Variables       []*Variable
 	Outputs         []*Output
@@ -28,6 +28,7 @@ type Config struct {
 // For example, Terraform needs to set the AWS access keys for the AWS
 // resource provider.
 type ProviderConfig struct {
+	Name      string
 	RawConfig *RawConfig
 }
 
@@ -99,9 +100,10 @@ type UserVariable struct {
 // ProviderConfigName returns the name of the provider configuration in
 // the given mapping that maps to the proper provider configuration
 // for this resource.
-func ProviderConfigName(t string, pcs map[string]*ProviderConfig) string {
+func ProviderConfigName(t string, pcs []*ProviderConfig) string {
 	lk := ""
-	for k, _ := range pcs {
+	for _, v := range pcs {
+		k := v.Name
 		if strings.HasPrefix(t, k) && len(k) > len(lk) {
 			lk = k
 		}

config/config_test.go

@@ -151,11 +151,11 @@ func TestNewUserVariable(t *testing.T) {
 }
 
 func TestProviderConfigName(t *testing.T) {
-	pcs := map[string]*ProviderConfig{
-		"aw":   new(ProviderConfig),
-		"aws":  new(ProviderConfig),
-		"a":    new(ProviderConfig),
-		"gce_": new(ProviderConfig),
+	pcs := []*ProviderConfig{
+		&ProviderConfig{Name: "aw"},
+		&ProviderConfig{Name: "aws"},
+		&ProviderConfig{Name: "a"},
+		&ProviderConfig{Name: "gce_"},
 	}
 
 	n := ProviderConfigName("aws_instance", pcs)

config/loader_libucl.go

@@ -234,7 +234,7 @@ func loadOutputsLibucl(o *libucl.Object) ([]*Output, error) {
 
 // LoadProvidersLibucl recurses into the given libucl object and turns
 // it into a mapping of provider configs.
-func loadProvidersLibucl(o *libucl.Object) (map[string]*ProviderConfig, error) {
+func loadProvidersLibucl(o *libucl.Object) ([]*ProviderConfig, error) {
 	objects := make(map[string]*libucl.Object)
 
 	// Iterate over all the "provider" blocks and get the keys along with
@@ -252,8 +252,12 @@ func loadProvidersLibucl(o *libucl.Object) (map[string]*ProviderConfig, error) {
 	}
 	iter.Close()
 
+	if len(objects) == 0 {
+		return nil, nil
+	}
+
 	// Go through each object and turn it into an actual result.
-	result := make(map[string]*ProviderConfig)
+	result := make([]*ProviderConfig, 0, len(objects))
 	for n, o := range objects {
 		var config map[string]interface{}
 
@@ -269,9 +273,10 @@ func loadProvidersLibucl(o *libucl.Object) (map[string]*ProviderConfig, error) {
 				err)
 		}
 
-		result[n] = &ProviderConfig{
+		result = append(result, &ProviderConfig{
+			Name:      n,
 			RawConfig: rawConfig,
-		}
+		})
 	}
 
 	return result, nil

config/loader_test.go

@@ -248,17 +248,19 @@ func TestLoad_connections(t *testing.T) {
 
 // This helper turns a provider configs field into a deterministic
 // string value for comparison in tests.
-func providerConfigsStr(pcs map[string]*ProviderConfig) string {
+func providerConfigsStr(pcs []*ProviderConfig) string {
 	result := ""
 
 	ns := make([]string, 0, len(pcs))
-	for n, _ := range pcs {
-		ns = append(ns, n)
+	m := make(map[string]*ProviderConfig)
+	for _, n := range pcs {
+		ns = append(ns, n.Name)
+		m[n.Name] = n
 	}
 	sort.Strings(ns)
 
 	for _, n := range ns {
-		pc := pcs[n]
+		pc := m[n]
 
 		result += fmt.Sprintf("%s\n", n)
 

config/merge.go

@@ -68,12 +68,19 @@ func Merge(c1, c2 *Config) (*Config, error) {
 
 	// Merge provider configs: If they collide, we just take the latest one
 	// for now. In the future, we might provide smarter merge functionality.
-	c.ProviderConfigs = make(map[string]*ProviderConfig)
-	for k, v := range c1.ProviderConfigs {
-		c.ProviderConfigs[k] = v
-	}
-	for k, v := range c2.ProviderConfigs {
-		c.ProviderConfigs[k] = v
+	if len(c1.ProviderConfigs) > 0 || len(c2.ProviderConfigs) > 0 {
+		m := make(map[string]*ProviderConfig)
+		for _, v := range c1.ProviderConfigs {
+			m[v.Name] = v
+		}
+		for _, v := range c2.ProviderConfigs {
+			m[v.Name] = v
+		}
+
+		c.ProviderConfigs = make([]*ProviderConfig, 0, len(m))
+		for _, v := range m {
+			c.ProviderConfigs = append(c.ProviderConfigs, v)
+		}
 	}
 
 	// Merge resources: If they collide, we just take the latest one

terraform/graph.go

@@ -462,7 +462,8 @@ func graphAddProviderConfigs(g *depgraph.Graph, c *config.Config) {
 		}
 
 		// Look up the provider config for this resource
-		pcName := config.ProviderConfigName(resourceNode.Type, c.ProviderConfigs)
+		pcName := config.ProviderConfigName(
+			resourceNode.Type, c.ProviderConfigs)
 		if pcName == "" {
 			continue
 		}
@@ -470,11 +471,19 @@ func graphAddProviderConfigs(g *depgraph.Graph, c *config.Config) {
 		// We have one, so build the noun if it hasn't already been made
 		pcNoun, ok := pcNouns[pcName]
 		if !ok {
+			var pc *config.ProviderConfig
+			for _, v := range c.ProviderConfigs {
+				if v.Name == pcName {
+					pc = v
+					break
+				}
+			}
+
 			pcNoun = &depgraph.Noun{
 				Name: fmt.Sprintf("provider.%s", pcName),
 				Meta: &GraphNodeResourceProvider{
 					ID:     pcName,
-					Config: c.ProviderConfigs[pcName],
+					Config: pc,
 				},
 			}
 			pcNouns[pcName] = pcNoun