Fix LoadConfig to correctly initialize DebugHelper

LogLevel must be read after json.Unmarshal().

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

Author: Kazuyoshi Kato

config/config.go

@@ -94,14 +94,14 @@ func LoadConfig(path string) (*Config, error) {
 		},
 	}
 
+	if err := json.Unmarshal(data, cfg); err != nil {
+		return nil, errors.Wrapf(err, "failed to unmarshal config from %q", path)
+	}
+
 	cfg.DebugHelper, err = debug.New(cfg.LogLevels...)
 	if err != nil {
 		return nil, err
 	}
 
-	if err := json.Unmarshal(data, cfg); err != nil {
-		return nil, errors.Wrapf(err, "failed to unmarshal config from %q", path)
-	}
-
 	return cfg, nil
 }

config/config_test.go

@@ -47,7 +47,8 @@ func TestLoadConfigOverrides(t *testing.T) {
 			"kernel_image_path":"%s",
 			"root_drive":"%s",
 			"cpu_count": %d,
-            "cpu_template": "%s"
+            "cpu_template": "%s",
+			"log_levels": ["debug"]
 		}`, overrideKernelArgs, overrideKernelPath, overrideRootfsPath, overrideCPUCount, overrideCPUTemplate)
 	configFile, cleanup := createTempConfig(t, configContent)
 	defer cleanup()
@@ -58,6 +59,8 @@ func TestLoadConfigOverrides(t *testing.T) {
 	assert.Equal(t, overrideKernelPath, cfg.KernelImagePath, "expected overridden kernel path")
 	assert.Equal(t, overrideRootfsPath, cfg.RootDrive, "expected overridden rootfs path")
 	assert.Equal(t, overrideCPUTemplate, cfg.CPUTemplate, "expected overridden CPU template")
+
+	assert.True(t, cfg.DebugHelper.LogFirecrackerOutput())
 }
 
 func createTempConfig(t *testing.T, contents string) (string, func()) {