[Bug]: output file not cleared before writing, causing broken JSON

[rite7sh]

What happened?

When I run uiconv multiple times on the same output file, the file is not cleared before writing. If the new output is smaller than the previous one, some old data remains at the end of the file. This results in broken/invalid JSON.
the test i used:

package main

import (
	"fmt"
	"os"
)

func main() {
	file := "/tmp/out.json"

	long := `{"data": [{"traceID": "abc123", "spans": [{"spanID": "s1", "operationName": "op1"}]}]}`
	short := `{"data": []}`

	// first write
	f, err := os.OpenFile(file, os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}
	f.WriteString(long)
	f.Close()

	data1, _ := os.ReadFile(file)
	fmt.Println("first write:")
	fmt.Println(string(data1))
	fmt.Println("size:", len(data1))
	fmt.Println()

	// second write (same flags)
	f, err = os.OpenFile(file, os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}
	f.WriteString(short)
	f.Close()

	data2, _ := os.ReadFile(file)
	fmt.Println("second write:")
	fmt.Println(string(data2))
	fmt.Println("size:", len(data2))
	fmt.Println()

	// fix with truncation
	f, err = os.OpenFile(file, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
	if err != nil {
		panic(err)
	}
	f.WriteString(short)
	f.Close()

	data3, _ := os.ReadFile(file)
	fmt.Println("with trunc:")
	fmt.Println(string(data3))
	fmt.Println("size:", len(data3))

	os.Remove(file)
}

Steps to reproduce

1. Run uiconv with a large input file and save output to out.json
2. Run uiconv again with a smaller input file using the same output file
3. Open out.json

I noticed extra old data at the end of the file.

Expected behavior

The output file should be cleared before writing.

It should only contain the latest JSON and no leftover data from previous runs.

Relevant log output

second write:
{"data": []}traceID": "abc123", "spans": [{"spanID": "s1", "operationName": "op1"}]}]}
size: 86

Screenshot

did a 3 write test and the log output :

Additional context

In extractor.go:

The file is opened using: os.OpenFile(uiFile, os.O_CREATE|os.O_WRONLY, os.ModePerm),

Since O_TRUNC is not used, the file is not cleared before writing.
A simple fix would be:
os.OpenFile(uiFile, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.ModePerm)

Jaeger backend version

main branch (local build)

SDK

irrelevant to bug

Pipeline

NA

Stogage backend

NA

Operating system

Linux (WSL)

Deployment model

Local development (running code from repository)

Deployment configs

NA

[rite7sh]

@abhay1999 i guess the changes you did were direct replica of fix i linked, please look if there is any active pr as i did link here #8232 addressing the issue before opening a PR which avoids the duplication of effort :)

[abhay1999]

You're right, sorry about that — I missed #8232 before opening my PR. I'll close #8234 to avoid duplication. Good luck with your PR!