问题
I have a multi-threading Python program, and a utility function, writeLog(message), that writes out a timestamp followed by the message. Unfortunately, the resultant log file gives no indication of which thread is generating which message.
I would like writeLog() to be able to add something to the message to identify which thread is calling it. Obviously I could just make the threads pass this information in, but that would be a lot more work. Is there some thread equivalent of os.getpid() that I could use?
回答1:
threading.get_ident() works, or threading.current_thread().ident (or threading.currentThread().ident for Python < 2.6).
回答2:
Using the logging module you can automatically add the current thread identifier in each log entry. Just use one of these LogRecord mapping keys in your logger format string:
%(thread)d : Thread ID (if available).
%(threadName)s : Thread name (if available).
and set up your default handler with it:
logging.basicConfig(format="%(threadName)s:%(message)s")
回答3:
The thread.get_ident() function returns a long integer on Linux. It's not really a thread id.
I use this method to really get the thread id on Linux:
import ctypes
libc = ctypes.cdll.LoadLibrary('libc.so.6')
# System dependent, see e.g. /usr/include/x86_64-linux-gnu/asm/unistd_64.h
SYS_gettid = 186
def getThreadId():
"""Returns OS thread id - Specific to Linux"""
return libc.syscall(SYS_gettid)
回答4:
I saw examples of thread IDs like this:
class myThread(threading.Thread):
def __init__(self, threadID, name, counter):
self.threadID = threadID
...
The threading module docs lists name attribute as well:
...
A thread has a name.
The name can be passed to the constructor,
and read or changed through the name attribute.
...
Thread.name
A string used for identification purposes only.
It has no semantics. Multiple threads may
be given the same name. The initial name is set by the constructor.
回答5:
This functionality is now supported by Python 3.8+ :)
https://github.com/python/cpython/commit/4959c33d2555b89b494c678d99be81a65ee864b0
https://github.com/python/cpython/pull/11993
回答6:
You can get the ident of the current running thread. The ident could be reused for other threads, if the current thread ends.
When you crate an instance of Thread, a name is given implicit to the thread, which is the pattern: Thread-number
The name has no meaning and the name don't have to be unique. The ident of all running threads is unique.
import threading
def worker():
print(threading.current_thread().name)
print(threading.get_ident())
threading.Thread(target=worker).start()
threading.Thread(target=worker, name='foo').start()
The function threading.current_thread() returns the current running thread. This object holds the whole information of the thread.
回答7:
I created multiple threads in Python, I printed the thread objects, and I printed the id using the ident variable. I see all the ids are same:
<Thread(Thread-1, stopped 140500807628544)>
<Thread(Thread-2, started 140500807628544)>
<Thread(Thread-3, started 140500807628544)>
回答8:
Similarly to @brucexin I needed to get OS-level thread identifier (which != thread.get_ident()) and use something like below not to depend on particular numbers and being amd64-only:
---- 8< ---- (xos.pyx)
"""module xos complements standard module os"""
cdef extern from "<sys/syscall.h>":
long syscall(long number, ...)
const int SYS_gettid
# gettid returns current OS thread identifier.
def gettid():
return syscall(SYS_gettid)
and
---- 8< ---- (test.py)
import pyximport; pyximport.install()
import xos
...
print 'my tid: %d' % xos.gettid()
this depends on Cython though.
来源：https://stackoverflow.com/questions/919897/how-to-find-a-thread-id-in-python