feat: CP-1062 Remove excessive information returned from reading log files

Author: samueld-activator

internal/runners/mcp/downloadlogs/downloadlogs.go

@@ -1,6 +1,8 @@
 package downloadlogs
 
 import (
+	"bufio"
+	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
@@ -29,20 +31,52 @@ func NewParams(logUrl string) *Params {
 	}
 }
 
+// Example: {"body": {"facility": "INFO", "msg": "..."}, "artifact_id": "...", "timestamp": "2025-08-12T19:23:51.702971", "type": "artifact_progress", "source": "build-wrapper", "pid": 19}
+type LogLine struct {
+	Body struct {
+		Msg string `json:"msg"`
+	} `json:"body"`
+}
+
 func (runner *DownloadLogsRunner) Run(params *Params) error {
 	response, err := http.Get(params.logUrl)
 	if err != nil {
 		return fmt.Errorf("error while downloading logs: %v", err)
 	}
 	defer response.Body.Close()
 
-	body, err := io.ReadAll(response.Body)
-	if err != nil {
-		return fmt.Errorf("error reading response body: %v", err)
-	}
 	if response.StatusCode != 200 {
+		body, _ := io.ReadAll(response.Body)
 		return fmt.Errorf("error fetching logs: status %d, %s", response.StatusCode, body)
 	}
-	runner.output.Print(string(body))
+
+	scanner := bufio.NewScanner(response.Body)
+
+	startPrinting := false
+
+	for scanner.Scan() {
+		var logLine LogLine
+		line := scanner.Text()
+
+		if err := json.Unmarshal([]byte(line), &logLine); err != nil {
+			continue // Skip malformed lines
+		}
+
+		msg := logLine.Body.Msg
+
+		if !startPrinting {
+			if msg == "Dependencies downloaded and unpacked." {
+				startPrinting = true
+			}
+			continue
+		}
+
+		runner.output.Print(msg + "\n")
+	}
+
+	if err := scanner.Err(); err != nil {
+		return fmt.Errorf("error reading log content: %v", err)
+	}
+
 	return nil
 }