GCP auth logic (#333)

* purposal commit

* helper func for loading gcp creds

Author: dacbd

iterative/gcp/provider.go

@@ -12,6 +12,8 @@ import (
 	"strings"
 	"time"
 
+	"terraform-provider-iterative/iterative/utils"
+
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
 	gcp_compute "google.golang.org/api/compute/v1"
@@ -289,7 +291,7 @@ func getProjectService() (string, *gcp_compute.Service, error) {
 	var credentials *google.Credentials
 	var err error
 
-	if credentialsData := []byte(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS_DATA")); len(credentialsData) > 0 {
+	if credentialsData := []byte(utils.LoadGCPCredentials()); len(credentialsData) > 0 {
 		credentials, err = google.CredentialsFromJSON(oauth2.NoContext, credentialsData, gcp_compute.ComputeScope)
 	} else {
 		credentials, err = google.FindDefaultCredentials(oauth2.NoContext, gcp_compute.ComputeScope)

iterative/resource_runner.go

@@ -431,7 +431,7 @@ func provisionerCode(d *schema.ResourceData) (string, error) {
 	data["AZURE_CLIENT_SECRET"] = os.Getenv("AZURE_CLIENT_SECRET")
 	data["AZURE_SUBSCRIPTION_ID"] = os.Getenv("AZURE_SUBSCRIPTION_ID")
 	data["AZURE_TENANT_ID"] = os.Getenv("AZURE_TENANT_ID")
-	data["GOOGLE_APPLICATION_CREDENTIALS_DATA"] = os.Getenv("GOOGLE_APPLICATION_CREDENTIALS_DATA")
+	data["GOOGLE_APPLICATION_CREDENTIALS_DATA"] = utils.LoadGCPCredentials()
 	data["KUBERNETES_CONFIGURATION"] = os.Getenv("KUBERNETES_CONFIGURATION")
 	data["container"] = isContainerAvailable(d.Get("cloud").(string))
 	data["setup"] = strings.Replace(string(setup[:]), "#/bin/sh", "", 1)

iterative/utils/helpers.go

@@ -1,6 +1,8 @@
 package utils
 
 import (
+	"os"
+
 	"github.com/aohorodnyk/uid"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 )
@@ -31,3 +33,15 @@ func StripAvailabilityZone(region string) string {
 	}
 	return region
 }
+
+func LoadGCPCredentials() string {
+	credentialsData := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS_DATA")
+	if len(credentialsData) == 0 {
+		credentialsPath := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
+		if len(credentialsPath) > 0 {
+			jsonData, _ := os.ReadFile(credentialsPath)
+			credentialsData = string(jsonData)
+		}
+	}
+	return credentialsData
+}