Pythonで作ったデーモンにREST APIをつける話 ref: http://qiita.com/knoguchi/items/385fe91038760c856530

file0.diff

$ diff -u example.py example_threaded.py
--- example.py  2016-12-20 16:19:19.000000000 -0800
+++ example_threaded.py 2016-12-20 16:23:43.000000000 -0800
@@ -1,6 +1,13 @@
+import logging
+import threading
+
 from flask import request, url_for
 from flask.ext.api import FlaskAPI, status, exceptions

+FORMAT = '%(asctime)-15s %(name)s %(threadName)s %(message)s'
+logging.basicConfig(format=FORMAT, level=logging.INFO)
+log = logging.getLogger()
+
 app = FlaskAPI(__name__)


@@ -53,5 +60,14 @@


 if __name__ == "__main__":
-    app.run(debug=True)
+
+    log.info('start')
+    rest_service_thread = threading.Thread(name='reset_service', target=app.run, kwargs=dict(debug=True))
+    rest_service_thread.start()
+    log.info('main thread is mine!')
+    import time
+    while True:
+        print(time.ctime())
+        time.sleep(1)
+    rest_service_thread.join()

file1.txt

2016-12-20 16:30:32,129 root MainThread start
2016-12-20 16:30:32,130 root MainThread main thread is mine!
Tue Dec 20 16:30:32 2016
2016-12-20 16:30:32,141 werkzeug reset_service  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
Exception in thread reset_service:
Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/lib/python3.5/threading.py", line 914, in _bootstrap_inner
    self.run()
  File "/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/lib/python3.5/threading.py", line 862, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/knoguchi/.virtualenvs/flask3/lib/python3.5/site-packages/flask/app.py", line 843, in run
    run_simple(host, port, self, **options)
  File "/Users/knoguchi/.virtualenvs/flask3/lib/python3.5/site-packages/werkzeug/serving.py", line 692, in run_simple
    reloader_type)
  File "/Users/knoguchi/.virtualenvs/flask3/lib/python3.5/site-packages/werkzeug/_reloader.py", line 242, in run_with_reloader
    signal.signal(signal.SIGTERM, lambda *args: sys.exit(0))
  File "/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/lib/python3.5/signal.py", line 47, in signal
    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
ValueError: signal only works in main thread

Tue Dec 20 16:30:33 2016
Tue Dec 20 16:30:34 2016

file2.txt

2016-12-20 16:38:54,214 root MainThread start
2016-12-20 16:38:54,215 root MainThread main thread is mine!
Tue Dec 20 16:38:54 2016
2016-12-20 16:38:54,224 werkzeug reset_service  * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
Tue Dec 20 16:38:55 2016
2016-12-20 16:38:55,840 werkzeug reset_service 127.0.0.1 - - [20/Dec/2016 16:38:55] "GET / HTTP/1.1" 200 -
Tue Dec 20 16:38:56 2016
2016-12-20 16:38:56,827 werkzeug reset_service 127.0.0.1 - - [20/Dec/2016 16:38:56] "GET / HTTP/1.1" 200 -
Tue Dec 20 16:38:57 2016

file3.diff

$ diff -u example_threaded.py example_threaded2.py
--- example_threaded.py 2016-12-20 17:17:10.000000000 -0800
+++ example_threaded2.py    2016-12-20 17:29:06.000000000 -0800
@@ -23,7 +23,38 @@
         'text': notes[key]
     }

+def synchronized(lock):
+    """ Synchronization decorator. """

+    def wrap(f):
+        def newFunction(*args, **kw):
+            lock.acquire()
+            try:
+                return f(*args, **kw)
+            finally:
+                lock.release()
+        return newFunction
+    return wrap
+
+glock = threading.Lock()
+
+@synchronized(glock)
+def list_notes():
+    return [note_repr(idx) for idx in sorted(notes.keys())]
+
+@synchronized(glock)
+def add_note(note):
+    idx = max(notes.keys()) + 1
+    notes[idx] = note
+    return idx
+@synchronized(glock)
+def update_note(key, note):
+    notes[key] = note
+
+@synchronized(glock)
+def delete_note(key):
+    return notes.pop(key, None)
+
 @app.route("/", methods=['GET', 'POST'])
 def notes_list():
     """
@@ -31,12 +62,11 @@
     """
     if request.method == 'POST':
         note = str(request.data.get('text', ''))
-        idx = max(notes.keys()) + 1
-        notes[idx] = note
+        idx = add_note(note)
         return note_repr(idx), status.HTTP_201_CREATED

     # request.method == 'GET'
-    return [note_repr(idx) for idx in sorted(notes.keys())]
+    return list_notes()


 @app.route("/<int:key>/", methods=['GET', 'PUT', 'DELETE'])
@@ -46,11 +76,11 @@
     """
     if request.method == 'PUT':
         note = str(request.data.get('text', ''))
-        notes[key] = note
+        update_note(key, note)
         return note_repr(key)

     elif request.method == 'DELETE':
-        notes.pop(key, None)
+        delete_note(key)
         return '', status.HTTP_204_NO_CONTENT

     # request.method == 'GET'
@@ -60,14 +90,15 @@


 if __name__ == "__main__":
-
+
     log.info('start')
-    rest_service_thread = threading.Thread(name='reset_service', target=app.run, kwargs=dict(debug=True))
+    rest_service_thread = threading.Thread(name='reset_service', target=app.run, kwargs=dict())
     rest_service_thread.start()
     log.info('main thread is mine!')
-    import time
-    while True:
-        print(time.ctime())
-        time.sleep(1)
+    import sys
+    for line in iter(sys.stdin):
+        if not line:
+            break
+        add_note(line.strip())
     rest_service_thread.join()

file4.diff

--- example_threaded2.py    2016-12-25 16:25:08.000000000 -0800
+++ example_daemon.py   2016-12-25 16:29:29.000000000 -0800
@@ -1,8 +1,9 @@
 import logging
 import threading
+import daemon

 from flask import request, url_for
-from flask.ext.api import FlaskAPI, status, exceptions
+from flask_api import FlaskAPI, status, exceptions

 FORMAT = '%(asctime)-15s %(name)s %(threadName)s %(message)s'
 logging.basicConfig(format=FORMAT, level=logging.INFO)
@@ -89,16 +90,16 @@
     return note_repr(key)


-if __name__ == "__main__":
-
+def main():
     log.info('start')
     rest_service_thread = threading.Thread(name='reset_service', target=app.run, kwargs=dict(threaded=True))
     rest_service_thread.start()
     log.info('main thread is mine!')
-    import sys
-    for line in iter(sys.stdin):
-        if not line:
-            break
-        add_note(line.strip())
+    import time
+    for i in range(10):
+        add_note("note{}".format(i))
+        time.sleep(3)
     rest_service_thread.join()

+with daemon.DaemonContext():
+    main()

file4.txt

import logging
import threading

from flask import request, url_for
from flask.ext.api import FlaskAPI, status, exceptions

FORMAT = '%(asctime)-15s %(name)s %(threadName)s %(message)s'
logging.basicConfig(format=FORMAT, level=logging.INFO)
log = logging.getLogger()

app = FlaskAPI(__name__)


notes = {
    0: 'do the shopping',
    1: 'build the codez',
    2: 'paint the door',
}

def note_repr(key):
    return {
        'url': request.host_url.rstrip('/') + url_for('notes_detail', key=key),
        'text': notes[key]
    }

def synchronized(lock):
    """ Synchronization decorator. """

    def wrap(f):
        def newFunction(*args, **kw):
            lock.acquire()
            try:
                return f(*args, **kw)
            finally:
                lock.release()
        return newFunction
    return wrap

glock = threading.Lock()

@synchronized(glock)
def list_notes():
    return [note_repr(idx) for idx in sorted(notes.keys())]

@synchronized(glock)
def add_note(note):
    idx = max(notes.keys()) + 1
    notes[idx] = note
    return idx
@synchronized(glock)
def update_note(key, note):
    notes[key] = note

@synchronized(glock)
def delete_note(key):
    return notes.pop(key, None)

@app.route("/", methods=['GET', 'POST'])
def notes_list():
    """
    List or create notes.
    """
    if request.method == 'POST':
        note = str(request.data.get('text', ''))
        idx = add_note(note)
        return note_repr(idx), status.HTTP_201_CREATED

    # request.method == 'GET'
    return list_notes()


@app.route("/<int:key>/", methods=['GET', 'PUT', 'DELETE'])
def notes_detail(key):
    """
    Retrieve, update or delete note instances.
    """
    if request.method == 'PUT':
        note = str(request.data.get('text', ''))
        update_note(key, note)
        return note_repr(key)

    elif request.method == 'DELETE':
        delete_note(key)
        return '', status.HTTP_204_NO_CONTENT

    # request.method == 'GET'
    if key not in notes:
        raise exceptions.NotFound()
    return note_repr(key)


if __name__ == "__main__":

    log.info('start')
    rest_service_thread = threading.Thread(name='reset_service', target=app.run, kwargs=dict(threaded=True))
    rest_service_thread.start()
    log.info('main thread is mine!')
    import sys
    for line in iter(sys.stdin):
        if not line:
            break
        add_note(line.strip())
    rest_service_thread.join()

file5.txt

$ python example_daemon.py
$

file6.txt

$ ps xao pid,ppid,pgid,sid,comm | grep python
 2860     1  2859  2859 python

file7.txt

lsof -p 2860
COMMAND  PID USER   FD   TYPE  DEVICE SIZE/OFF    NODE NAME
python  2860 root  cwd    DIR   254,1     4096       2 /
python  2860 root  rtd    DIR   254,1     4096       2 /
python  2860 root  txt    REG   254,1  3781768  264936 /usr/bin/python2.7
python  2860 root  mem    REG   254,1    47712 1045078 /lib/x86_64-linux-gnu/libnss_files-2.19.so
python  2860 root  mem    REG   254,1    54248  391882 /usr/lib/python2.7/lib-dynload/_json.x86_64-linux-gnu.so
python  2860 root  mem    REG   254,1    18904 1044589 /lib/x86_64-linux-gnu/libuuid.so.1.3.0
python  2860 root  mem    REG   254,1    31048  265571 /usr/lib/x86_64-linux-gnu/libffi.so.6.0.2
python  2860 root  mem    REG   254,1   141184  392622 /usr/lib/python2.7/lib-dynload/_ctypes.x86_64-linux-gnu.so
python  2860 root  mem    REG   254,1    10464  796274 /usr/lib/python2.7/dist-packages/markupsafe/_speedups.so
python  2860 root  mem    REG   254,1    29464  392892 /usr/lib/python2.7/lib-dynload/_hashlib.x86_64-linux-gnu.so
python  2860 root  mem    REG   254,1  2066816  264782 /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.0
python  2860 root  mem    REG   254,1   395176  264784 /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
python  2860 root  mem    REG   254,1    97872  392612 /usr/lib/python2.7/lib-dynload/_ssl.x86_64-linux-gnu.so
python  2860 root  mem    REG   254,1    11248  392000 /usr/lib/python2.7/lib-dynload/resource.x86_64-linux-gnu.so
python  2860 root  mem    REG   254,1  1607712  269275 /usr/lib/locale/locale-archive
python  2860 root  mem    REG   254,1  1738176 1045067 /lib/x86_64-linux-gnu/libc-2.19.so
python  2860 root  mem    REG   254,1  1051056 1045072 /lib/x86_64-linux-gnu/libm-2.19.so
python  2860 root  mem    REG   254,1   109144 1044580 /lib/x86_64-linux-gnu/libz.so.1.2.8
python  2860 root  mem    REG   254,1    10680 1045291 /lib/x86_64-linux-gnu/libutil-2.19.so
python  2860 root  mem    REG   254,1    14664 1045071 /lib/x86_64-linux-gnu/libdl-2.19.so
python  2860 root  mem    REG   254,1   137440 1044987 /lib/x86_64-linux-gnu/libpthread-2.19.so
python  2860 root  mem    REG   254,1   140928 1044988 /lib/x86_64-linux-gnu/ld-2.19.so
python  2860 root    0u   CHR     1,3      0t0    5593 /dev/null
python  2860 root    1u   CHR     1,3      0t0    5593 /dev/null
python  2860 root    2u   CHR     1,3      0t0    5593 /dev/null
python  2860 root    3u  IPv4 3596677      0t0     TCP localhost:5000 (LISTEN)

file8.txt

import logging
import threading
import daemon

from flask import request, url_for
from flask_api import FlaskAPI, status, exceptions

FORMAT = '%(asctime)-15s %(name)s %(threadName)s %(message)s'
logging.basicConfig(format=FORMAT, level=logging.INFO)
log = logging.getLogger()

app = FlaskAPI(__name__)


notes = {
    0: 'do the shopping',
    1: 'build the codez',
    2: 'paint the door',
}

def note_repr(key):
    return {
        'url': request.host_url.rstrip('/') + url_for('notes_detail', key=key),
        'text': notes[key]
    }

def synchronized(lock):
    """ Synchronization decorator. """

    def wrap(f):
        def newFunction(*args, **kw):
            lock.acquire()
            try:
                return f(*args, **kw)
            finally:
                lock.release()
        return newFunction
    return wrap

glock = threading.Lock()

@synchronized(glock)
def list_notes():
    return [note_repr(idx) for idx in sorted(notes.keys())]

@synchronized(glock)
def add_note(note):
    idx = max(notes.keys()) + 1
    notes[idx] = note
    return idx
@synchronized(glock)
def update_note(key, note):
    notes[key] = note

@synchronized(glock)
def delete_note(key):
    return notes.pop(key, None)

@app.route("/", methods=['GET', 'POST'])
def notes_list():
    """
    List or create notes.
    """
    if request.method == 'POST':
        note = str(request.data.get('text', ''))
        idx = add_note(note)
        return note_repr(idx), status.HTTP_201_CREATED

    # request.method == 'GET'
    return list_notes()


@app.route("/<int:key>/", methods=['GET', 'PUT', 'DELETE'])
def notes_detail(key):
    """
    Retrieve, update or delete note instances.
    """
    if request.method == 'PUT':
        note = str(request.data.get('text', ''))
        update_note(key, note)
        return note_repr(key)

    elif request.method == 'DELETE':
        delete_note(key)
        return '', status.HTTP_204_NO_CONTENT

    # request.method == 'GET'
    if key not in notes:
        raise exceptions.NotFound()
    return note_repr(key)


def main():
    log.info('start')
    rest_service_thread = threading.Thread(name='reset_service', target=app.run, kwargs=dict(threaded=True))
    rest_service_thread.start()
    log.info('main thread is mine!')
    import time
    for i in range(10):
        add_note("note{}".format(i))
        time.sleep(3)
    rest_service_thread.join()

with daemon.DaemonContext():
    main()