From bcf989fe0ea170c4f01383a70ba552e663d69109 Mon Sep 17 00:00:00 2001
From: mjdenkowski <michael.j.denkowski@gmail.com>
Date: Fri, 18 Apr 2014 17:36:58 -0400
Subject: Each grammar extractor gets its own process to avoid Cython
 segfaults.

---
 realtime/rt/rt.py | 64 +++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 57 insertions(+), 7 deletions(-)

diff --git a/realtime/rt/rt.py b/realtime/rt/rt.py
index 27eeb3ca..70ed0c3c 100644
--- a/realtime/rt/rt.py
+++ b/realtime/rt/rt.py
@@ -5,6 +5,7 @@ import collections
 import logging
 import os
 import shutil
+import signal
 import StringIO
 import subprocess
 import sys
@@ -25,6 +26,54 @@ TRUE = ('true', 'True', 'TRUE')
 
 logger = logging.getLogger('rt')
 
+class ExtractorWrapper:
+    '''Wrap cdec.sa.GrammarExtractor.  Used to keep multiple instances of the extractor from causing Python to segfault.
+       Do not use directly unless you know what you're doing.'''
+
+    def __init__(self, config):
+        # Make sure pycdec is on PYTHONPATH
+        cdec_root = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+        pycdec = os.path.join(cdec_root, 'python')
+        env = os.environ.copy()
+        python_path = env.get('PYTHONPATH', '')
+        if 'cdec/python' not in python_path:
+            python_path = '{}:{}'.format(python_path, pycdec) if len(python_path) > 0 else pycdec
+            env['PYTHONPATH'] = python_path
+        # Start grammar extractor as separate process using stdio
+        cmd = ['python', '-m', 'cdec.sa.extract', '-o', '-z', '-c', config, '-t']
+        logger.info('Executing: {}'.format(' '.join(cmd)))
+        self.p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env)
+        util.consume_stream(self.p.stderr)
+        self.lock = util.FIFOLock()
+
+    def close(self, force=False):
+        if not force:
+            self.lock.acquire()
+            self.p.stdin.close()
+            self.p.wait()
+            self.lock.release()
+        else:
+            os.kill(self.p.pid, signal.SIGTERM)
+            
+
+    def drop_ctx(self, ctx_name):
+        self.lock.acquire()
+        self.p.stdin.write('{} ||| drop\n'.format(ctx_name))
+        self.p.stdout.readline()
+        self.lock.release()
+
+    def grammar(self, sentence, grammar_file, ctx_name):
+        self.lock.acquire()
+        self.p.stdin.write('{} ||| {} ||| {}\n'.format(ctx_name, sentence, grammar_file))
+        self.p.stdout.readline()
+        self.lock.release()
+
+    def add_instance(self, source, target, alignment, ctx_name):
+        self.lock.acquire()
+        self.p.stdin.write('{} ||| {} ||| {} ||| {}\n'.format(ctx_name, source, target, alignment))
+        self.p.stdout.readline()
+        self.lock.release()
+
 class RealtimeDecoder:
     '''Do not use directly unless you know what you're doing.  Use RealtimeTranslator.'''
 
@@ -111,7 +160,7 @@ class RealtimeTranslator:
         sa_config.filename = os.path.join(self.tmp, 'sa.ini')
         util.sa_ini_for_realtime(sa_config, os.path.abspath(configdir))
         sa_config.write()
-        self.extractor = cdec.sa.GrammarExtractor(sa_config.filename, online=True)
+        self.extractor = ExtractorWrapper(sa_config.filename)
         self.cache_size = cache_size
 
         ### One instance per context
@@ -142,10 +191,13 @@ class RealtimeTranslator:
         '''Cleanup'''
         if force:
             logger.info('Forced shutdown: stopping immediately')
-        for ctx_name in list(self.ctx_names):
-            self.drop_ctx(ctx_name, force)
+        # Drop contexts before closing processes unless forced
+        if not force:
+            for ctx_name in list(self.ctx_names):
+                self.drop_ctx(ctx_name, force)
         logger.info('Closing processes')
         self.aligner.close(force)
+        self.extractor.close(force)
         if self.norm:
             if not force:
                 self.tokenizer_lock.acquire()
@@ -213,11 +265,9 @@ class RealtimeTranslator:
             self.extractor_lock.release()
             return grammar_file
         # Extract and cache
-        (fid, grammar_file) = tempfile.mkstemp(dir=self.decoders[ctx_name].tmp, prefix='grammar.')
+        (fid, grammar_file) = tempfile.mkstemp(dir=self.decoders[ctx_name].tmp, prefix='grammar.', suffix='.gz')
         os.close(fid)
-        with open(grammar_file, 'w') as output:
-            for rule in self.extractor.grammar(sentence, ctx_name):
-                output.write('{}\n'.format(str(rule)))
+        self.extractor.grammar(sentence, grammar_file, ctx_name)
         grammar_files = self.grammar_files[ctx_name]
         if len(grammar_files) == self.cache_size:
             rm_sent = grammar_files.popleft()
-- 
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