fix: splited temperatures

Changes:
- Split temperatures from log file into blocks.
  Every block has a size of 500 entries. Every block would be send to
  the remote host

pkg/httpcall/temperature.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"math"
 	"net/http"
 
 	"git.cryptic.systems/fh-trier/go-flucky/pkg/config"
@@ -20,34 +21,54 @@ func SendTemperatures(temperatures []*stypes.Temperature, configDir string) erro
 		return err
 	}
 
-	temperaturesAsBytes, err := json.Marshal(temperatures)
-	if err != nil {
-		return fmt.Errorf("Can not marshal temperatures to JSON: %v", err)
+	// split temperatures in blocks to reduce server data size in single request
+	blockSize := 500
+	temperatureBlocks := make(map[int][]*stypes.Temperature)
+	length := int(math.Ceil(float64(len(temperatures)) / float64(blockSize)))
+	for i := 0; i < length; i++ {
+		start := i * blockSize
+		end := (i + 1) * blockSize
+
+		if end > len(temperatures) {
+			end = len(temperatures)
+		}
+
+		temperatureBlocks[i] = temperatures[start:end]
 	}
 
-	temperaturesAsReader := bytes.NewReader(temperaturesAsBytes)
-
 	for _, remote := range cnf.Remotes {
+
 		if remote.Enabled {
-			requestURL := fmt.Sprintf("%s%s", remote.Address, "/temperatures")
-			req, err := http.NewRequest("POST", requestURL, temperaturesAsReader)
-			if err != nil {
-				return err
-			}
 
-			client := http.Client{}
-			resp, err := client.Do(req)
-			if err != nil {
-				return err
-			}
-			defer resp.Body.Close()
+			for _, temperatureBlock := range temperatureBlocks {
 
-			if resp.StatusCode < 200 || resp.StatusCode > 299 {
-				b, err := ioutil.ReadAll(resp.Body)
+				temperaturesAsBytes, err := json.Marshal(temperatureBlock)
 				if err != nil {
-					return fmt.Errorf("Invalid HTTP-Statuscode - expected 200, got %d - can not read response body: %v", resp.StatusCode, err)
+					return fmt.Errorf("Can not marshal temperatures to JSON: %v", err)
+				}
+
+				temperaturesAsReader := bytes.NewReader(temperaturesAsBytes)
+
+				requestURL := fmt.Sprintf("%s%s", remote.Address, "/temperatures")
+				req, err := http.NewRequest("POST", requestURL, temperaturesAsReader)
+				if err != nil {
+					return err
+				}
+
+				client := http.Client{}
+				resp, err := client.Do(req)
+				if err != nil {
+					return err
+				}
+				defer resp.Body.Close()
+
+				if resp.StatusCode < 200 || resp.StatusCode > 299 {
+					b, err := ioutil.ReadAll(resp.Body)
+					if err != nil {
+						return fmt.Errorf("Invalid HTTP-Statuscode - expected 200, got %d - can not read response body: %v", resp.StatusCode, err)
+					}
+					return fmt.Errorf("Invalid HTTP-Statuscode - expected 200, got %d: %v", resp.StatusCode, string(b))
 				}
-				return fmt.Errorf("Invalid HTTP-Statuscode - expected 200, got %d: %v", resp.StatusCode, string(b))
 			}
 		}
 	}