[Kimchi-devel] [PATCH 2/4] Implement the package manager monitor backend

[Jose Ricardo Ziviani]

 - The client will be able to know if there is a package manager instance
    running and to follow the package manager logfiles to know what is
    happening within.

Signed-off-by: Jose Ricardo Ziviani <joserz at linux.vnet.ibm.com>
---
 plugins/kimchi/control/host.py |  1 +
 plugins/kimchi/model/host.py   | 10 ++++++++
 plugins/kimchi/swupdate.py     | 54 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 65 insertions(+)

diff --git a/plugins/kimchi/control/host.py b/plugins/kimchi/control/host.py
index 0a40f1b..6c2ed43 100644
--- a/plugins/kimchi/control/host.py
+++ b/plugins/kimchi/control/host.py
@@ -39,6 +39,7 @@ class Host(Resource):
         self.packagesupdate = PackagesUpdate(self.model)
         self.repositories = Repositories(self.model)
         self.swupdate = self.generate_action_handler_task('swupdate')
+        self.taillogs = self.generate_action_handler_task('taillogs')
         self.cpuinfo = CPUInfo(self.model)
 
     @property
diff --git a/plugins/kimchi/model/host.py b/plugins/kimchi/model/host.py
index 23fda3b..a159f0e 100644
--- a/plugins/kimchi/model/host.py
+++ b/plugins/kimchi/model/host.py
@@ -128,6 +128,16 @@ class HostModel(object):
             self.host_info['memory'] = psutil.virtual_memory().total
         return self.host_info
 
+    def taillogs(self, *name):
+        try:
+            swupdate = SoftwareUpdate()
+        except:
+            raise OperationFailed('KCHPKGUPD0004E')
+
+        taskid = add_task('/plugins/kimchi/host/taillogs',
+                          swupdate.tailUpdateLogs, self.objstore, None)
+        return self.task.lookup(taskid)
+
     def swupdate(self, *name):
         try:
             swupdate = SoftwareUpdate()
diff --git a/plugins/kimchi/swupdate.py b/plugins/kimchi/swupdate.py
index 4d92731..6045467 100644
--- a/plugins/kimchi/swupdate.py
+++ b/plugins/kimchi/swupdate.py
@@ -18,6 +18,7 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 
 import fcntl
+import os
 import subprocess
 import time
 
@@ -112,6 +113,59 @@ class SoftwareUpdate(object):
         self._scanUpdates()
         return self._num2update
 
+    def tailUpdateLogs(self, cb, params):
+        """
+        When the package manager is already running (started outside kimchi or
+        if wokd is restarted) we can only know what's happening by reading the
+        logfiles. This method acts like a 'tail -f' on the default package
+        manager logfile. If the logfile is not found, a simple '*' is
+        displayed to track progress. This will be until the process finishes.
+        """
+        if not self._pkg_mnger.isRunning():
+            return
+
+        fd = None
+        try:
+            fd = os.open(self._pkg_mnger.logfile, os.O_RDONLY)
+
+        # cannot open logfile, print something to let users know that the
+        # system is being upgrading until the package manager finishes its
+        # job
+        except (TypeError, OSError):
+            msgs = []
+            while self._pkg_mnger.isRunning():
+                msgs.append('*')
+                cb(''.join(msgs))
+                time.sleep(1)
+            msgs.append('\n')
+            cb(''.join(msgs), True)
+            return
+
+        # go to the end of logfile and starts reading, if nothing is read or
+        # a pattern is not found in the message just wait and retry until
+        # the package manager finishes
+        os.lseek(fd, 0, os.SEEK_END)
+        msgs = []
+        progress = []
+        while True:
+            read = os.read(fd, 1024)
+            if not read:
+                if not self._pkg_mnger.isRunning():
+                    break
+
+                if not msgs:
+                    progress.append('*')
+                    cb(''.join(progress))
+
+                time.sleep(1)
+                continue
+
+            msgs.append(read)
+            cb(''.join(msgs))
+
+        os.close(fd)
+        return cb(''.join(msgs), True)
+
     def doUpdate(self, cb, params):
         """
         Execute the update
-- 
1.9.1