cli: fix a bug in operator API when setting HTTPS via address. (#14635)

Operators may have a setup whereby the TLS config comes from a
source other than setting Nomad specific env vars. In this case,
we should attempt to identify the scheme using the config setting
as a fallback.

.changelog/14635.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+cli: fixed a bug in the `operator api` command where the HTTPS scheme was not always correctly calculated
+```

command/operator_api.go

@@ -386,22 +386,41 @@ func tlsToCurl(parts []string, tlsConfig *api.TLSConfig) []string {
 	return parts
 }
 
-// pathToURL converts a curl path argumet to URL. Paths without a host are
+// pathToURL converts a curl path argument to URL. Paths without a host are
 // prefixed with $NOMAD_ADDR or http://127.0.0.1:4646.
+//
+// Callers should pass a config generated by Meta.clientConfig which ensures
+// all default values are set correctly. Failure to do so will likely result in
+// a nil-pointer.
 func pathToURL(config *api.Config, path string) (*url.URL, error) {
-	// If the scheme is missing, add it
+
+	// If the scheme is missing from the path, it likely means the path is just
+	// the HTTP handler path. Attempt to infer this.
 	if !strings.HasPrefix(path, "http://") && !strings.HasPrefix(path, "https://") {
 		scheme := "http"
-		if config.TLSConfig != nil {
-			if config.TLSConfig.CACert != "" ||
-				config.TLSConfig.CAPath != "" ||
-				config.TLSConfig.ClientCert != "" ||
-				config.TLSConfig.TLSServerName != "" ||
-				config.TLSConfig.Insecure {
 
-				// TLS configured, but scheme not set. Assume
-				// https.
-				scheme = "https"
+		// If the user has set any TLS configuration value, this is a good sign
+		// Nomad is running with TLS enabled. Otherwise, use the address within
+		// the config to identify a scheme.
+		if config.TLSConfig.CACert != "" ||
+			config.TLSConfig.CAPath != "" ||
+			config.TLSConfig.ClientCert != "" ||
+			config.TLSConfig.TLSServerName != "" ||
+			config.TLSConfig.Insecure {
+
+			// TLS configured, but scheme not set. Assume https.
+			scheme = "https"
+		} else if config.Address != "" {
+
+			confURL, err := url.Parse(config.Address)
+			if err != nil {
+				return nil, fmt.Errorf("unable to parse configured address: %v", err)
+			}
+
+			// Ensure we only overwrite the set scheme value if the parsing
+			// identified a valid scheme.
+			if confURL.Scheme == "http" || confURL.Scheme == "https" {
+				scheme = confURL.Scheme
 			}
 		}
 
@@ -413,7 +432,7 @@ func pathToURL(config *api.Config, path string) (*url.URL, error) {
 		return nil, err
 	}
 
-	// If URL.Scheme is empty, use defaults from client config
+	// If URL.Host is empty, use defaults from client config.
 	if u.Host == "" {
 		confURL, err := url.Parse(config.Address)
 		if err != nil {

command/operator_api_test.go

@@ -8,8 +8,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/nomad/api"
 	"github.com/hashicorp/nomad/ci"
 	"github.com/mitchellh/cli"
+	"github.com/shoenig/test/must"
 	"github.com/stretchr/testify/require"
 )
 
@@ -106,3 +108,65 @@ func TestOperatorAPICommand_Curl(t *testing.T) {
 `
 	require.Equal(t, expected, buf.String())
 }
+
+func Test_pathToURL(t *testing.T) {
+	ci.Parallel(t)
+
+	testCases := []struct {
+		name              string
+		inputConfig       *api.Config
+		inputPath         string
+		expectedOutputURL string
+	}{
+		{
+			name: "https address via config",
+			inputConfig: &api.Config{
+				Address:   "https://nomad.systems:4646",
+				TLSConfig: &api.TLSConfig{},
+			},
+			inputPath:         "/v1/jobs",
+			expectedOutputURL: "https://nomad.systems:4646/v1/jobs",
+		},
+		{
+			name: "http address via config",
+			inputConfig: &api.Config{
+				Address:   "http://nomad.systems:4646",
+				TLSConfig: &api.TLSConfig{},
+			},
+			inputPath:         "/v1/jobs",
+			expectedOutputURL: "http://nomad.systems:4646/v1/jobs",
+		},
+		{
+			name:              "https address via path",
+			inputConfig:       api.DefaultConfig(),
+			inputPath:         "https://nomad.systems:4646/v1/jobs",
+			expectedOutputURL: "https://nomad.systems:4646/v1/jobs",
+		},
+		{
+			name:              "http address via path",
+			inputConfig:       api.DefaultConfig(),
+			inputPath:         "http://nomad.systems:4646/v1/jobs",
+			expectedOutputURL: "http://nomad.systems:4646/v1/jobs",
+		},
+		{
+			name: "https inferred by tls config",
+			inputConfig: &api.Config{
+				Address: "http://127.0.0.1:4646",
+				TLSConfig: &api.TLSConfig{
+					CAPath: "/path/to/nowhere",
+				},
+			},
+			inputPath:         "/v1/jobs",
+			expectedOutputURL: "https://127.0.0.1:4646/v1/jobs",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			actualOutput, err := pathToURL(tc.inputConfig, tc.inputPath)
+			must.NoError(t, err)
+			must.NotNil(t, actualOutput)
+			must.Eq(t, actualOutput.String(), tc.expectedOutputURL)
+		})
+	}
+}