Add --show-output option to parallel_emerge which prints output from jobs.

Also update parallel_emerge to print output in general if you hit
CTRL-C or if a job is running for more than an hour. Also cleanup exit
handling so that emerge exits a bit more cleanly, and so that we don't
hang if emerge throws an Exception.

BUG=none
TEST=Ran ./parallel_emerge --show-output -uDNve chromeos

Review URL: http://codereview.chromium.org/3010056

parallel_emerge

@@ -38,14 +38,17 @@ Basic operation:
       of the same package for a runtime dep).
 """
 
+import codecs
 import copy
 import multiprocessing
 import os
 import Queue
 import shlex
+import signal
 import sys
 import tempfile
 import time
+import traceback
 import urllib2
 
 # If PORTAGE_USERNAME isn't specified, scrape it from the $HOME variable. On
@@ -214,7 +217,7 @@ class DepGraphGenerator(object):
   """
 
   __slots__ = ["board", "emerge", "mandatory_source", "no_workon_deps",
-               "package_db", "rebuild"]
+               "package_db", "rebuild", "show_output"]
 
   def __init__(self):
     self.board = None
@@ -223,6 +226,7 @@ class DepGraphGenerator(object):
     self.no_workon_deps = False
     self.package_db = {}
     self.rebuild = False
+    self.show_output = False
 
   def ParseParallelEmergeArgs(self, argv):
     """Read the parallel emerge arguments from the command-line.
@@ -249,6 +253,8 @@ class DepGraphGenerator(object):
         self.no_workon_deps = True
       elif arg == "--rebuild":
         self.rebuild = True
+      elif arg == "--show-output":
+        self.show_output = True
       else:
         # Not one of our options, so pass through to emerge.
         emerge_args.append(arg)
@@ -1067,20 +1073,72 @@ def PrintDepsMap(deps_map):
       print "    no dependencies"
 
 
-def EmergeWorker(task_queue, done_queue, emerge, package_db):
+class EmergeJobState(object):
+  __slots__ = ["done", "filename", "last_output_seek", "last_output_timestamp",
+               "pkgname", "retcode", "start_timestamp", "target"]
+
+  def __init__(self, target, pkgname, done, filename, start_timestamp,
+               retcode=None):
+
+    # The full name of the target we're building (e.g.
+    # chromeos-base/chromeos-0.0.1-r60)
+    self.target = target
+
+    # The short name of the target we're building (e.g. chromeos-0.0.1-r60)
+    self.pkgname = pkgname
+
+    # Whether the job is done. (True if the job is done; false otherwise.)
+    self.done = done
+
+    # The filename where output is currently stored.
+    self.filename = filename
+
+    # The location (in bytes) of the end of the last complete line we printed.
+    # This starts off at zero. We use this to jump to the right place when we
+    # print output from the same ebuild multiple times.
+    self.last_output_seek = 0
+
+    # The timestamp of the last time we printed output. Since we haven't
+    # printed output yet, this starts at zero.
+    self.last_output_timestamp = 0
+
+    # The return code of our job, if the job is actually finished.
+    self.retcode = retcode
+
+    # The timestamp when our job started.
+    self.start_timestamp = start_timestamp
+
+
+def EmergeWorker(task_queue, job_queue, emerge, package_db):
   """This worker emerges any packages given to it on the task_queue.
 
   Args:
     task_queue: The queue of tasks for this worker to do.
-    done_queue: The queue of results from the worker.
+    job_queue: The queue of results from the worker.
     emerge: An EmergeData() object.
     package_db: A dict, mapping package ids to portage Package objects.
 
   It expects package identifiers to be passed to it via task_queue. When
-  the package is merged, it pushes (target, retval, outputstr) into the
+  a task is started, it pushes the (target, filename) to the started_queue.
-  done_queue.
+  The output is stored in filename. When a merge starts or finishes, we push
+  EmergeJobState objects to the job_queue.
   """
 
+  def ExitHandler(signum, frame):
+    # Remove our signal handlers so we don't get called recursively.
+    signal.signal(signal.SIGINT, signal.SIG_DFL)
+    signal.signal(signal.SIGTERM, signal.SIG_DFL)
+
+    # Try to exit cleanly
+    sys.exit(1)
+
+  # Ensure that we exit quietly and cleanly, if possible, when we receive
+  # SIGTERM or SIGINT signals. By default, when the user hits CTRL-C, all
+  # of the child processes will print details about KeyboardInterrupt
+  # exceptions, which isn't very helpful.
+  signal.signal(signal.SIGINT, ExitHandler)
+  signal.signal(signal.SIGTERM, ExitHandler)
+
   settings, trees, mtimedb = emerge.settings, emerge.trees, emerge.mtimedb
   opts, spinner = emerge.opts, emerge.spinner
   opts["--nodeps"] = True
@@ -1088,14 +1146,16 @@ def EmergeWorker(task_queue, done_queue, emerge, package_db):
     # Wait for a new item to show up on the queue. This is a blocking wait,
     # so if there's nothing to do, we just sit here.
     target = task_queue.get()
-    print "Emerging", target
     db_pkg = package_db[target]
     db_pkg.root_config = emerge.root_config
     install_list = [db_pkg]
-    output = tempfile.TemporaryFile()
+    pkgname = db_pkg.pf
-    outputstr = ""
+    output = tempfile.NamedTemporaryFile(prefix=pkgname + "-", delete=False)
+    start_timestamp = time.time()
+    job = EmergeJobState(target, pkgname, False, output.name, start_timestamp)
+    job_queue.put(job)
     if "--pretend" in opts:
-      retval = 0
+      retcode = 0
     else:
       save_stdout = sys.stdout
       save_stderr = sys.stderr
@@ -1104,30 +1164,34 @@ def EmergeWorker(task_queue, done_queue, emerge, package_db):
         sys.stderr = output
         scheduler = Scheduler(settings, trees, mtimedb, opts, spinner,
                               install_list, [], emerge.scheduler_graph)
-        retval = scheduler.merge()
+        retcode = scheduler.merge()
+      except Exception:
+        traceback.print_exc(file=output)
+        retcode = 1
       finally:
         sys.stdout = save_stdout
         sys.stderr = save_stderr
-      if retval is None:
+        output.close()
-        retval = 0
+      if retcode is None:
-      if retval != 0:
+        retcode = 0
-        output.seek(0)
-        outputstr = output.read()
 
-    done_queue.put((target, retval, outputstr))
+    job = EmergeJobState(target, pkgname, True, output.name, start_timestamp,
+                         retcode)
+    job_queue.put(job)
 
 
 class EmergeQueue(object):
   """Class to schedule emerge jobs according to a dependency graph."""
 
-  def __init__(self, deps_map, emerge, package_db):
+  def __init__(self, deps_map, emerge, package_db, show_output):
     # Store the dependency graph.
     self._deps_map = deps_map
     # Initialize the running queue to empty
-    self._jobs = set()
+    self._jobs = {}
     # List of total package installs represented in deps_map.
     install_jobs = [x for x in deps_map if deps_map[x]["action"] == "merge"]
     self._total_jobs = len(install_jobs)
+    self._show_output = show_output
 
     if "--pretend" in emerge.opts:
       print "Skipping merge because of --pretend mode."
@@ -1140,21 +1204,48 @@ class EmergeQueue(object):
     procs = min(self._total_jobs,
                 emerge.opts.get("--jobs", multiprocessing.cpu_count()))
     self._emerge_queue = multiprocessing.Queue()
-    self._done_queue = multiprocessing.Queue()
+    self._job_queue = multiprocessing.Queue()
-    args = (self._emerge_queue, self._done_queue, emerge, package_db)
+    args = (self._emerge_queue, self._job_queue, emerge, package_db)
     self._pool = multiprocessing.Pool(procs, EmergeWorker, args)
 
     # Initialize the failed queue to empty.
     self._retry_queue = []
-    self._failed = {}
+    self._failed = set()
 
     # Print an update before we launch the merges.
     self._Status()
 
+    # Setup an exit handler so that we print nice messages if we are
+    # terminated.
+    self._SetupExitHandler()
+
+    # Schedule our jobs.
     for target, info in deps_map.items():
       if not info["needs"]:
         self._Schedule(target)
 
+  def _SetupExitHandler(self):
+
+    def ExitHandler(signum, frame):
+
+      # Kill our signal handlers so we don't get called recursively
+      signal.signal(signal.SIGINT, signal.SIG_DFL)
+      signal.signal(signal.SIGTERM, signal.SIG_DFL)
+
+      # Print our current job status
+      for target, job in self._jobs.iteritems():
+        if job:
+          self._PrintJob(job)
+          os.unlink(job.filename)
+
+      # Notify the user that we are exiting
+      print "Exiting on signal %s" % signum
+      sys.exit(1)
+
+    # Print out job status when we are killed
+    signal.signal(signal.SIGINT, ExitHandler)
+    signal.signal(signal.SIGTERM, ExitHandler)
+
   def _Schedule(self, target):
     # We maintain a tree of all deps, if this doesn't need
     # to be installed just free up it's children and continue.
@@ -1165,16 +1256,56 @@ class EmergeQueue(object):
       self._Finish(target)
     else:
       # Kick off the build if it's marked to be built.
-      self._jobs.add(target)
+      self._jobs[target] = None
       self._emerge_queue.put(target)
 
   def _LoadAvg(self):
     loads = open("/proc/loadavg", "r").readline().split()[:3]
     return " ".join(loads)
 
+  def _PrintJob(self, job):
+    """Print output so far of specified job"""
+
+    # Calculate how long the job has been running.
+    current_time = time.time()
+    seconds = current_time - job.start_timestamp
+
+    # Note that we've printed out the job so far.
+    job.last_output_timestamp = current_time
+
+    # Note that we're starting the job
+    info = "job %s (%dm%.1fs) ===" % (job.pkgname, seconds / 60, seconds % 60)
+    if job.last_output_seek:
+      print "=== Continue output for %s " % info
+    else:
+      print "=== Start output for %s ===" % info
+
+    # Print actual output from job
+    f = codecs.open(job.filename, encoding='utf-8', errors='replace')
+    f.seek(job.last_output_seek)
+    prefix = job.pkgname + ":"
+    for line in f:
+
+      # Save off our position in the file
+      if line and line[-1] == "\n":
+        job.last_output_seek = f.tell()
+        line = line[:-1]
+
+      # Print our line
+      print prefix, line.encode('utf-8', 'replace')
+    f.close()
+
+    # Note end of output section
+    if job.done:
+      print "=== Complete: %s ===" % info
+    else:
+      print "=== Still running: %s ===" % info
+
+
   def _Status(self):
     """Print status."""
-    seconds = time.time() - GLOBAL_START
+    current_time = time.time()
+    seconds = current_time - GLOBAL_START
     line = ("Pending %s, Ready %s, Running %s, Retrying %s, Total %s "
             "[Time %dm%.1fs Load %s]")
     qsize = self._emerge_queue.qsize()
@@ -1182,6 +1313,18 @@ class EmergeQueue(object):
                   len(self._retry_queue), self._total_jobs,
                   seconds / 60, seconds % 60, self._LoadAvg())
 
+    # Print interim output every minute if --show-output is used. Otherwise,
+    # only print output if a job has been running for 60 minutes or more.
+    if self._show_output:
+      interval = 60
+    else:
+      interval = 60 * 60
+    for target, job in self._jobs.iteritems():
+      if job:
+        last_timestamp = max(job.start_timestamp, job.last_output_timestamp)
+        if last_timestamp + interval < current_time:
+          self._PrintJob(job)
+
   def _Finish(self, target):
     """Mark a target as completed and unblock dependecies."""
     for dep in self._deps_map[target]["provides"]:
@@ -1205,7 +1348,7 @@ class EmergeQueue(object):
     while self._deps_map:
       # Check here that we are actually waiting for something.
       if (self._emerge_queue.empty() and
-          self._done_queue.empty() and
+          self._job_queue.empty() and
           not self._jobs and
           self._deps_map):
         # If we have failed on a package, retry it now.
@@ -1213,11 +1356,10 @@ class EmergeQueue(object):
           self._Retry()
         # If we have failed a package twice, just give up.
         elif self._failed:
-          for failure, output in self._failed.items():
+          for failure in self._failed:
             print "Package failed: %s" % failure
-            print output
           PrintDepsMap(self._deps_map)
-          print "Packages failed: %s" % " ,".join(self._failed.keys())
+          print "Packages failed: %s" % " ,".join(self._failed)
           sys.exit(1)
         # If we have dependency cycles.
         else:
@@ -1226,27 +1368,39 @@ class EmergeQueue(object):
           sys.exit(1)
 
       try:
-        target, retcode, output = self._done_queue.get(timeout=5)
+        job = self._job_queue.get(timeout=5)
       except Queue.Empty:
         # Print an update.
         self._Status()
         continue
 
-      self._jobs.discard(target)
+      target = job.target
 
-      # Print if necessary.
+      if not job.done:
-      if retcode != 0:
+        self._jobs[target] = job
-        print output
+        print "Started %s (logged in %s)" % (target, job.filename)
-      if retcode != 0:
+        continue
+
+      # Print output of job
+      if self._show_output or job.retcode != 0:
+        self._PrintJob(job)
+      os.unlink(job.filename)
+      del self._jobs[target]
+
+      seconds = time.time() - job.start_timestamp
+      details = "%s (in %dm%.1fs)" % (target, seconds / 60, seconds % 60)
+
+      # Complain if necessary.
+      if job.retcode != 0:
         # Handle job failure.
         if target in self._failed:
           # If this job has failed previously, give up.
-          print "Failed %s. Your build has failed." % target
+          print "Failed %s. Your build has failed." % details
         else:
           # Queue up this build to try again after a long while.
           self._retry_queue.append(target)
-          self._failed[target] = 1
+          self._failed.add(target)
-          print "Failed %s, retrying later." % target
+          print "Failed %s, retrying later." % details
       else:
         if target in self._failed and self._retry_queue:
           # If we have successfully retried a failed package, and there
@@ -1254,7 +1408,7 @@ class EmergeQueue(object):
           # one retrying package actively running at a time.
           self._Retry()
 
-        print "Completed %s" % target
+        print "Completed %s" % details
         # Mark as completed and unblock waiting ebuilds.
         self._Finish(target)
 
@@ -1305,7 +1459,7 @@ def main():
     PrintDepsMap(deps_graph)
 
   # Run the queued emerges.
-  scheduler = EmergeQueue(deps_graph, emerge, deps.package_db)
+  scheduler = EmergeQueue(deps_graph, emerge, deps.package_db, deps.show_output)
   scheduler.Run()
 
   # Update world.