update env checks to work nicely in a service runtime

policy/storage/gcs.go

@@ -3,6 +3,7 @@ package storage
 import (
 	"context"
 	"net/http"
+	"os"
 
 	"github.com/atomist-skills/go-skill/policy/goals"
 	"github.com/atomist-skills/go-skill/util"
@@ -14,6 +15,11 @@ import (
 )
 
 func getBucketName() string {
+	bucket := os.Getenv("POLICY_STORAGE_BUCKET")
+	if bucket != "" {
+		return bucket
+	}
+
 	if util.IsStaging() {
 		return "atm-policy-evaluation-results-staging"
 	}

util/environment.go

@@ -8,6 +8,11 @@ import (
 // Return whether the skill runs on staging or not, using the same logic as the TypeScript code.
 // ref: https://github.com/atomist-skills/skill/blob/21696f154efded41f4cb98eb0e6951ab81839b8c/lib/util.ts#L235-L240
 func IsStaging() bool {
+	environment, found := os.LookupEnv("SKILL_ENVIRONMENT")
+	if found {
+		return environment == "staging"
+	}
+
 	url, found := os.LookupEnv("ATOMIST_GRAPHQL_ENDPOINT")
 	if !found {
 		url = "https://automation.atomist.com/graphql"