calculate num of buffered entries correctly

- clear buffer after flush

internals/overlord/logstate/loki.go

@@ -20,7 +20,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"strconv"
 	"strings"
@@ -46,12 +45,20 @@ func newLokiClient(target *plan.LogTarget) logClient {
 
 func (c *lokiClient) Write(ctx context.Context, entry servicelog.Entry) error {
 	c.entries[entry.Service] = append(c.entries[entry.Service], asLokiEntry(entry))
-	if len(c.entries) >= 10 {
+	if c.numEntries() >= 10 {
 		return c.Flush(ctx)
 	}
 	return nil
 }
 
+func (c *lokiClient) numEntries() int {
+	sum := 0
+	for _, l := range c.entries {
+		sum += len(l)
+	}
+	return sum
+}
+
 func asLokiEntry(entry servicelog.Entry) lokiEntry {
 	return lokiEntry{
 		strconv.FormatInt(entry.Time.UnixNano(), 10),
@@ -61,7 +68,9 @@ func asLokiEntry(entry servicelog.Entry) lokiEntry {
 
 func (c *lokiClient) Flush(ctx context.Context) error {
 	defer func() {
-		// TODO: clear entries
+		for svc := range c.entries {
+			c.entries[svc] = c.entries[svc][:0]
+		}
 	}()
 
 	// Build request
@@ -96,7 +105,7 @@ func (c *lokiClient) Flush(ctx context.Context) error {
 	// Check response status code to see if it was successful
 	if sc := resp.StatusCode; sc < 200 || sc >= 300 {
 		// Request to Loki failed
-		b, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1024))
+		b, err := io.ReadAll(io.LimitReader(resp.Body, 1024))
 		if err != nil {
 			b = append(b, []byte("//couldn't read response body: ")...)
 			b = append(b, []byte(err.Error())...)