Adds write-to-file flag to store data locally (#180)

* Adds write-to-file flag to store data locally

Only stores data locally if no organization is specified.
This can be added if needed.

Signed-off-by: Jamie Leppard <[email protected]>

* Restructure gatherAndPostData to allow local write

gatherAndPostData has been split into:
gatherData which returns config information, the prefight client
and readings.

postData which sends this data to preflight server as previously
happened in gatherAndPostData

The outputpath flag now determines if postData is called.
If the flag is set, postData is not called and the data is written
locally.

This also fixes the issue of the flag only working when no org is set.

Signed-off-by: Jamie Leppard <[email protected]>

* Breaks down gatherData into smaller functions

gatherData is broken down into:

getConfiguration - returns config and preflight client
this is now implemented outside of gatherAndOutputData
in the main Run loop

gatherData - creates data gatherers and generates readings
This is run inside gatherAndOutputData as previously done

Signed-off-by: Jamie Leppard <[email protected]>

Co-authored-by: Jamie Leppard <[email protected]>

Author: JammyL

cmd/agent.go

@@ -64,5 +64,12 @@ func init() {
 		false,
 		"Runs agent a single time if true, or continously if false",
 	)
+	agentCmd.PersistentFlags().StringVarP(
+		&agent.OutputPath,
+		"output-path",
+		"",
+		"",
+		"Output file path, if used will write data to a local file instead of uploading to the preflight server",
+	)
 
 }

pkg/agent/run.go

@@ -34,20 +34,23 @@ var OneShot bool
 // CredentialsPath is where the agent will try to loads the credentials. (Experimental)
 var CredentialsPath string
 
+// OutputPath is where the agent will write data to locally if specified
+var OutputPath string
 
 // Run starts the agent process
 func Run(cmd *cobra.Command, args []string) {
 	ctx := context.Background()
 	for {
-		gatherAndPostData(ctx)
+		config, preflightClient := getConfiguration(ctx)
+		gatherAndOutputData(ctx, config, preflightClient)
 		if OneShot {
 			break
 		}
 		time.Sleep(time.Duration(Period) * time.Second)
 	}
 }
 
-func gatherAndPostData(ctx context.Context) {
+func getConfiguration(ctx context.Context) (Config, *client.PreflightClient) {
 	log.Printf("Preflight agent version: %s (%s)", version.PreflightVersion, version.Commit)
 	file, err := os.Open(ConfigFilePath)
 	if err != nil {
@@ -127,6 +130,26 @@ func gatherAndPostData(ctx context.Context) {
 		}
 	}
 
+	return config, preflightClient
+}
+
+func gatherAndOutputData(ctx context.Context, config Config, preflightClient *client.PreflightClient) {
+	readings := gatherData(ctx, config)
+
+	if OutputPath != "" {
+		data, err := json.MarshalIndent(readings, " ", " ")
+		err = ioutil.WriteFile(OutputPath, data, 0644)
+		if err != nil {
+			log.Fatal(err)
+		}
+		log.Println("Data saved locally to", OutputPath)
+	} else {
+		postData(config, preflightClient, readings)
+	}
+}
+
+func gatherData(ctx context.Context, config Config) []*api.DataReading {
+
 	dataGatherers := make(map[string]datagatherer.DataGatherer)
 
 	for _, dgConfig := range config.DataGatherers {
@@ -172,6 +195,11 @@ func gatherAndPostData(ctx context.Context) {
 			strings.Join(failedDataGatherers, ", "),
 		)
 	}
+	return readings
+}
+
+func postData(config Config, preflightClient *client.PreflightClient, readings []*api.DataReading) {
+	baseURL := config.Server
 
 	log.Println("Running Agent...")
 	log.Println("Posting data to ", baseURL)
@@ -185,6 +213,7 @@ func gatherAndPostData(ctx context.Context) {
 			path = "/api/v1/datareadings"
 		}
 		res, err := preflightClient.Post(path, bytes.NewBuffer(data))
+
 		if err != nil {
 			log.Fatalf("Failed to post data: %+v", err)
 		}
@@ -199,7 +228,7 @@ func gatherAndPostData(ctx context.Context) {
 			log.Fatalf("Received response with status code %d. Body: %s", code, errorContent)
 		}
 	} else {
-		err = preflightClient.PostDataReadings(config.OrganizationID, readings)
+		err := preflightClient.PostDataReadings(config.OrganizationID, readings)
 		// TODO: handle errors gracefully: e.g. handle retries when it is possible
 		if err != nil {
 			log.Fatalf("Post to server failed: %+v", err)