Merge pull request #38 from FireTail-io/health-endpoint

Health endpoint

Author: TheTeaCat

README.md

@@ -142,6 +142,7 @@ Find below a full list of the environment variables used by the FireTail Lambda
 | `AWS_LAMBDA_EXEC_WRAPPER`  | None                                                        | Must be set to `/opt/firetail-wrapper.sh`.                   |
 | `FIRETAIL_API_TOKEN`       | None                                                        | Your API token for the FireTail Logging API. If left unset, no logs will be sent to the FireTail Logging API |
 | `FIRETAIL_API_URL`         | `https://api.logging.eu-west-1.prod.firetail.app/logs/bulk` | The URL of the FireTail Logging API                          |
+| `FIRETAIL_API_URL_HEALTH`  | `https://api.logging.eu-west-1.prod.firetail.app/health`    | The URL of a health endpoint to send a request to during startup to aid debugging |
 | `FIRETAIL_EXTENSION_DEBUG` | `false`                                                     | Enables debug logging from the extension if set to a value parsed as `true` by [strconv.ParseBool](https://pkg.go.dev/strconv#ParseBool) |
 | `FIRETAIL_LOG_BUFFER_SIZE` | `1000`                                                      | The maximum amount of logs the extension will hold in its buffer from which logs are batched and sent to FireTail |
 | `FIRETAIL_MAX_BATCH_SIZE`  | `100`                                                       | The maximum size of a batch of logs to be sent to the FireTail logging API in one request |

firetail/record_receiver.go

@@ -21,6 +21,7 @@ func RecordReceiver(recordsChannel chan Record, maxBatchSize int, firetailApiUrl
 		}
 
 		// Give the batch to the batch callback. If it errs, we continue
+		log.Printf("Attempting to send batch of %d record(s) to Firetail...", len(recordsBatch))
 		recordsSent, err := SendRecordsToSaaS(recordsBatch, firetailApiUrl, firetailApiToken)
 		if err != nil {
 			log.Println("Error sending records to Firetail:", err.Error())

main.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"net/http"
 	"os"
 	"path"
 	"strconv"
@@ -18,24 +19,43 @@ func main() {
 	// Configure logging
 	extensionName := path.Base(os.Args[0])
 	log.SetPrefix(fmt.Sprintf("[%s] ", extensionName))
-	if isDebug, err := strconv.ParseBool(os.Getenv("FIRETAIL_EXTENSION_DEBUG")); err != nil || !isDebug {
+	isDebug, err := strconv.ParseBool(os.Getenv("FIRETAIL_EXTENSION_DEBUG"))
+	if err != nil || !isDebug {
 		// If we're not in debug mode, we'll just send the logs to the void
 		log.SetOutput(ioutil.Discard)
 	} else {
 		log.Println("Firetail extension starting in debug mode.")
 	}
 
 	// Log the value of AWS_LAMBDA_EXEC_WRAPPER and AWS_LAMBDA_RUNTIME_API for debugging
-	log.Println("AWS_LAMBDA_EXEC_WRAPPER:", os.Getenv("AWS_LAMBDA_EXEC_WRAPPER"))
-	log.Println("AWS_LAMBDA_RUNTIME_API:", os.Getenv("AWS_LAMBDA_RUNTIME_API"))
+	if isDebug {
+		log.Println("AWS_LAMBDA_EXEC_WRAPPER:", os.Getenv("AWS_LAMBDA_EXEC_WRAPPER"))
+		log.Println("AWS_LAMBDA_RUNTIME_API:", os.Getenv("AWS_LAMBDA_RUNTIME_API"))
+	}
+
+	// If the health endpoint env var is set, make a request to it to check it's reachable
+	if healthEndpoint := os.Getenv("FIRETAIL_API_URL_HEALTH"); healthEndpoint != "" {
+		resp, err := http.Get(healthEndpoint)
+		if err != nil {
+			log.Println("Error making request to health endpoint:", err.Error())
+		} else {
+			defer resp.Body.Close()
+			healthResponse, err := ioutil.ReadAll(resp.Body)
+			if err != nil {
+				log.Println("Error reading health endpoint response:", err.Error())
+			} else {
+				log.Println("Health endpoint response:", strconv.Itoa(resp.StatusCode), string(healthResponse))
+			}
+		}
+	}
 
 	// This context will be cancelled whenever a SIGTERM or SIGINT signal is received
 	// We'll use it for our requests to the extensions API & to shutdown the log server
 	ctx := getContext()
 
 	// Create a Lambda Extensions API client & register our extension
 	extensionClient := extensionsapi.NewClient()
-	_, err := extensionClient.Register(ctx, extensionName)
+	_, err = extensionClient.Register(ctx, extensionName)
 	if err != nil {
 		panic(err)
 	}

proxy/proxy.go

@@ -146,18 +146,18 @@ func (p *ProxyServer) recordAssembler() {
 
 		eventBody, err := io.ReadAll(event.Body)
 		if err != nil {
-			log.Println("Error reading event body:", err)
+			log.Println("Error reading event body:", err.Error())
 			continue
 		}
 		responseBody, err := io.ReadAll(lambdaResponse.Body)
 		if err != nil {
-			log.Println("Error reading response body:", err)
+			log.Println("Error reading response body:", err.Error())
 			continue
 		}
 
 		var recordResponse firetail.RecordResponse
 		if err := json.Unmarshal(responseBody, &recordResponse); err != nil {
-			log.Println("Error unmarshalling response body:", err)
+			log.Println("Error unmarshalling response body:", err.Error())
 			continue
 		}