1. Error message:
(1) The file is occupied

[2019-12-18 14:18:25,165] admin-PC/ERROR/stderr: Traceback (most recent call last):
  File "d:\programs\python\python3.8\lib\site-packages\locust\core.py", line 394, in run
    self.execute_next_task()
  File "d:\programs\python\python3.8\lib\site-packages\locust\core.py", line 424, in execute_next_task
    self.execute_task(task["callable"], *task["args"], **task["kwargs"])
  File "d:\programs\python\python3.8\lib\site-packages\locust\core.py", line 436, in execute_task
    task(self, *args, **kwargs)
  File "G:\PycharmProjects\Locust_iwebshop_per\WorkFlow_Script\login_to_search.py", line 36, in search
    os.remove(file_res)
PermissionError: [WinError 32]  Another program is using this file and the process cannot access it.: 'SearchOutputdata.csv'

(2) Original code

    def search(self):
        file = open("Searchdata.csv","r")
        table = csv.reader(file)
        file_res = "search_output.csv"
        file_in = os.path.exists(file_res)
        if file_in:
            os.remove(file_res)
        file2 = open("search_output.csv","a")
        for row in table:
            keyword = row
            print(keyword)
            url = "/index.php?........&word="+str(keyword)
            response = self.client.get(url).text
            res = response.find(str(keyword))
            time1 = datetime.datetime.now()  # Get the current system time
            if res>=0:
                res = str(keyword)+"Query succeeded, test passed"+str(time1)
                file2.write(res+"\n")
            else:
                res = str(keyword)+"Query failed, test failed" + str(time1)
                file2.write(res + "\n")
        file2.close()

Second, the reason
Because of errors caused by concurrency, the same file cannot be written and opened at the same time, and can be read at the same time.

There is such logic in the code, you need to first determine whether the test report file exists, if it exists, delete it, if it does not exist, create a file to write a test report.

But because the performance test requires multiple users to operate, if one user is writing, and another user just needs to determine whether the file exists, this problem will occur afterwards.

and so:
You can use the judgment of the existence of this file in non-performance tests such as automated functions and interfaces, but in performance tests, users have concurrent operations, so it is not suitable for this logic

Third, solve
(1) This problem can be solved by combining the technology of web automation writing into the database and writing the test report information into the database table.
(2) If you really need to judge and write a test report, you can put this code to determine whether the file exists in the WebsiteUser class, and it must be placed before task_set