Allow SPACELIFT_API_TOKEN environment variable to be overridden

Updating the environment variable code to check for empty values. This allows `SPACELIFT_API_TOKEN` to be set to an empty string, giving the possibility to specify `SPACELIFT_API_KEY_ID` and `SPACELIFT_API_KEY_SECRET` inside a Spacelift run to use different credentials than the run credentials.

client/session/from_environment.go

@@ -36,40 +36,46 @@ const (
 	EnvSpaceliftAPIGitHubToken = "SPACELIFT_API_GITHUB_TOKEN" // #nosec G101
 )
 
+var (
+	errEnvSpaceliftAPIKeyID       = fmt.Errorf("%s missing from the environment", EnvSpaceliftAPIKeyID)
+	errEnvSpaceliftAPIKeySecret   = fmt.Errorf("%s missing from the environment", EnvSpaceliftAPIKeySecret)
+	errEnvSpaceliftAPIKeyEndpoint = fmt.Errorf("%s missing from the environment", EnvSpaceliftAPIKeyEndpoint)
+)
+
 // FromEnvironment creates a Spacelift session from the environment.
 func FromEnvironment(ctx context.Context, client *http.Client) func(func(string) (string, bool)) (Session, error) {
 	return func(lookup func(string) (string, bool)) (Session, error) {
 		if lookup == nil {
 			lookup = os.LookupEnv
 		}
 
-		if token, ok := lookup(EnvSpaceliftAPIToken); ok {
+		if token, ok := lookup(EnvSpaceliftAPIToken); ok && token != "" {
 			return FromAPIToken(ctx, client)(token)
 		}
 
 		endpoint, ok := lookup(EnvSpaceliftAPIKeyEndpoint)
-		if !ok {
+		if !ok || endpoint == "" {
 			// Keep backwards compatibility with older version of spacectl.
 			endpoint, ok = lookup(EnvSpaceliftAPIEndpoint)
 			if !ok {
-				return nil, fmt.Errorf("%s missing from the environment", EnvSpaceliftAPIKeyEndpoint)
+				return nil, errEnvSpaceliftAPIKeyEndpoint
 			}
 			fmt.Printf("Environment variable %q is deprecated, please use %q\n", EnvSpaceliftAPIEndpoint, EnvSpaceliftAPIKeyEndpoint)
 		}
 		endpoint = strings.TrimSuffix(endpoint, "/")
 
-		if gitHubToken, ok := lookup(EnvSpaceliftAPIGitHubToken); ok {
+		if gitHubToken, ok := lookup(EnvSpaceliftAPIGitHubToken); ok && gitHubToken != "" {
 			return FromGitHubToken(ctx, client)(endpoint, gitHubToken)
 		}
 
 		keyID, ok := lookup(EnvSpaceliftAPIKeyID)
-		if !ok {
-			return nil, fmt.Errorf("%s missing from the environment", EnvSpaceliftAPIKeyID)
+		if !ok || keyID == "" {
+			return nil, errEnvSpaceliftAPIKeyID
 		}
 
 		keySecret, ok := lookup(EnvSpaceliftAPIKeySecret)
-		if !ok {
-			return nil, fmt.Errorf("%s missing from the environment", EnvSpaceliftAPIKeySecret)
+		if !ok || keySecret == "" {
+			return nil, errEnvSpaceliftAPIKeySecret
 		}
 
 		return FromAPIKey(ctx, client)(endpoint, keyID, keySecret)

client/session/from_environment_test.go

@@ -0,0 +1,101 @@
+package session
+
+import (
+	"context"
+	"github.com/franela/goblin"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+// lookupWithEnv creates a custom lookup func which will return desired test values
+func lookupWithEnv(envSpaceliftAPIKeyEndpoint, envSpaceliftAPIToken, envSpaceliftAPIKeyID, envSpaceliftAPIKeySecret string) func(e string) (string, bool) {
+	return func(e string) (string, bool) {
+		s := ""
+		b := false
+
+		switch e {
+		case EnvSpaceliftAPIToken:
+			s = envSpaceliftAPIToken
+			b = true
+		case EnvSpaceliftAPIKeyEndpoint:
+			s = envSpaceliftAPIKeyEndpoint
+			b = true
+		case EnvSpaceliftAPIKeyID:
+			s = envSpaceliftAPIKeyID
+			b = true
+		case EnvSpaceliftAPIKeySecret:
+			s = envSpaceliftAPIKeySecret
+			b = true
+		}
+
+		return s, b
+	}
+}
+
+func TestFromEnvironment(t *testing.T) {
+	g := goblin.Goblin(t)
+
+	g.Describe("FromEnvironment", func() {
+		g.Describe("EnvSpaceliftAPIKeyEndpoint is not set", func() {
+			l := lookupWithEnv("", "", "abc123", "SuperSecret")
+			g.It("expect an error to find api endpoint in environment", func() {
+				_, err := FromEnvironment(context.TODO(), nil)(l)
+				g.Assert(err).Equal(errEnvSpaceliftAPIKeyEndpoint)
+			})
+		})
+
+		g.Describe("EnvSpaceliftAPIToken is set, EnvSpaceliftAPIKeyID is set, EnvSpaceliftAPIKeySecret is set", func() {
+			g.It("expect EnvSpaceliftAPIToken to be used and EnvSpaceliftAPIKeyID and EnvSpaceliftAPIKeySecret to be ignored", func() {
+				// Create a mock http server to handle JWT exchange
+				server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+					rw.Write([]byte(`{"data":{"apiKeyUser":{"jwt":"SuperSecretJWT","validUntil":123}}}`))
+				}))
+				// Close the server when test finishes
+				defer server.Close()
+				// API Token JWT generated at https://jwt.io/#debugger-io with contents:
+				//     Header: {"alg": "HS256","typ": "JWT"}
+				//     Payload: {"aud": "spacectl","exp": 1516239022}
+				l := lookupWithEnv(server.URL, "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJzcGFjZWN0bCIsImV4cCI6MTUxNjIzOTAyMn0.fsKd_N2TKXpx83JSPPw47zYzQ8sbSzGVPZcyGpwp05U", "abc123", "SuperSecret")
+				s, err := FromEnvironment(context.TODO(), server.Client())(l)
+				g.Assert(err).IsNil("expected no error when creating session")
+				g.Assert(s.Type()).Equal(CredentialsTypeAPIToken)
+			})
+		})
+
+		g.Describe("EnvSpaceliftAPIToken is an empty string", func() {
+			g.Describe("EnvSpaceliftAPIKeyID is set, EnvSpaceliftAPIKeySecret is set", func() {
+				g.It("expect a CredentialsTypeAPIKey session to be created", func() {
+					// Create a mock http server to handle JWT exchange
+					server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+						rw.Write([]byte(`{"data":{"apiKeyUser":{"jwt":"SuperSecretJWT","validUntil":123}}}`))
+					}))
+					// Close the server when test finishes
+					defer server.Close()
+
+					l := lookupWithEnv(server.URL, "", "abc123", "SuperSecret")
+
+					s, err := FromEnvironment(context.TODO(), server.Client())(l)
+					g.Assert(err).IsNil("expected no error when creating session")
+					g.Assert(s.Type()).Equal(CredentialsTypeAPIKey)
+				})
+			})
+
+			g.Describe("EnvSpaceliftAPIKeyID is an empty string, EnvSpaceliftAPIKeySecret is set", func() {
+				g.It("expect an error to find api key id in environment", func() {
+					l := lookupWithEnv("https://spacectl.app.spacelift.io", "", "", "SuperSecret")
+					_, err := FromEnvironment(context.TODO(), nil)(l)
+					g.Assert(err).Equal(errEnvSpaceliftAPIKeyID)
+				})
+			})
+
+			g.Describe("EnvSpaceliftAPIKeyID is set, EnvSpaceliftAPIKeySecret is an empty string", func() {
+				g.It("expect an error to find api key secret in environment", func() {
+					l := lookupWithEnv("https://spacectl.app.spacelift.io", "", "abc123", "")
+					_, err := FromEnvironment(context.TODO(), nil)(l)
+					g.Assert(err).Equal(errEnvSpaceliftAPIKeySecret)
+				})
+			})
+		})
+	})
+}