Update logging around passed variables and ovverriden variables.

This change adds some logging lines to provide greater feedback to
the user around variables file passed, CLI variables passed and
which variables are being used by Levant.

Closes #61

helper/variable.go

@@ -1,5 +1,7 @@
 package helper
 
+import "github.com/jrasell/levant/logging"
+
 // VariableMerge merges the passed file variables with the flag variabes to
 // provide a single set of variables. The flagVars will always prevale over file
 // variables.
@@ -8,13 +10,17 @@ func VariableMerge(fileVars *map[string]interface{}, flagVars *map[string]string
 	out := make(map[string]interface{})
 
 	for k, v := range *flagVars {
+		logging.Info("helper/variable: using command line variable with key %s and value %s", k, v)
 		out[k] = v
 	}
 
 	for k, v := range *fileVars {
 		if _, ok := out[k]; ok {
+			logging.Debug("helper/variable: variable from file with key %s and value %s overridden by CLI var",
+				k, v)
 			continue
 		}
+		logging.Info("helper/variable: using variable with key %s and value %v from file", k, v)
 		out[k] = v
 	}
 

levant/deploy.go

@@ -49,7 +49,8 @@ func (c *nomadClient) Deploy(job *nomad.Job, autoPromote int, forceCount bool) (
 
 	// If job.Type isn't set we can't continue
 	if job.Type == nil {
-		logging.Error("levant/deploy: Nomad job `type` is not set, should be set to `service`")
+		logging.Error("levant/deploy: Nomad job `type` is not set; should be set to `%s`, `%s` or `%s`",
+			nomadStructs.JobTypeBatch, nomadStructs.JobTypeSystem, nomadStructs.JobTypeService)
 		return
 	}
 

levant/templater.go

@@ -38,27 +38,39 @@ func RenderJob(templateFile, variableFile string, flagVars *map[string]string) (
 // RenderTemplate is the main entry point to render the template based on the
 // passed variables file.
 func RenderTemplate(templateFile, variableFile string, flagVars *map[string]string) (tpl *bytes.Buffer, err error) {
+
+	// Process the variable file extension and log DEBUG so the template can be
+	// correctly rendered.
 	ext := path.Ext(variableFile)
+	if variableFile != "" {
+		logging.Debug("levant/templater: variable file extension %s detected", ext)
+	}
 
 	src, err := ioutil.ReadFile(templateFile)
 	if err != nil {
 		return
 	}
 
+	// If no command line variables are passed; log this as DEBUG to provide much
+	// greater feedback.
+	if len(*flagVars) == 0 {
+		logging.Debug("levant/templater: no command line variables passed")
+	}
+
 	switch ext {
 	case terraformVarExtention:
-		logging.Debug("levant/templater: detected .tf variable file extension")
+		// Run the render using variables formatted in Terraforms .tf extension.
 		tpl, err = renderTFTemplte(string(src), variableFile, flagVars)
+
 	case yamlVarExtension, ymlVarExtension:
-		logging.Debug("levant/templater: detected .yaml or .yml variable file extension")
+		// Run the render using a YAML varaible file.
 		tpl, err = renderYAMLVarsTemplate(string(src), variableFile, flagVars)
-	case "":
-		if len(*flagVars) == 0 {
-			tpl = bytes.NewBuffer(src)
-		}
 
-		logging.Debug("levant/templater: variable file not passed, using any passed CLI variables")
+	case "":
+		// No varibles file passed; render using any passed CLI variables.
+		logging.Debug("levant/templater: variable file not passed")
 		tpl, err = readJobFile(string(src), flagVars)
+
 	default:
 		err = fmt.Errorf("variables file extension %v not supported", ext)
 	}