[gnome-continuous-yocto/gnomeostree-3.28-rocko: 3684/8267] buildstats.py: skip collecting unavailable /proc data

[Emmanuele Bassi <ebassi src gnome org>]

commit 9eb89487ff5a7e6965f3e3d696ef868d7901b13d
Author: Patrick Ohly <patrick ohly intel com>
Date:   Fri Dec 9 09:40:20 2016 +0100

    buildstats.py: skip collecting unavailable /proc data
    
    Some virtualized environments like Linux-VServer do not have the
    entries under /proc that the new system usage sampling expected,
    leading to an exception when trying to open the files.
    
    Now the presence of these files is checked once before enabling the
    corresponding data collection. When a file is missing, the
    corresponding log file is not written either and pybootchart will not
    draw the chart that normally displays the data.
    
    Errors while reading or writing of data samples is intentionally still
    a fatal error, because that points towards a bigger problem that
    should not be ignored.
    
    Reported-by: Andreas Oberritter <obi opendreambox org>
    (From OE-Core rev: daeee2d6731014c33f0d1f8a3846830c099932b4)
    
    Signed-off-by: Patrick Ohly <patrick ohly intel com>
    Signed-off-by: Ross Burton <ross burton intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/lib/buildstats.py |   19 ++++++++++++-------
 1 files changed, 12 insertions(+), 7 deletions(-)
---
diff --git a/meta/lib/buildstats.py b/meta/lib/buildstats.py
index 9e5b6be..854c387 100644
--- a/meta/lib/buildstats.py
+++ b/meta/lib/buildstats.py
@@ -18,13 +18,18 @@ class SystemStats:
                 ('meminfo', self._reduce_meminfo),
                 ('stat', self._reduce_stat),
         ):
-            # In practice, this class gets instantiated only once in
-            # the bitbake cooker process.  Therefore 'append' mode is
-            # not strictly necessary, but using it makes the class
-            # more robust should two processes ever write
-            # concurrently.
-            destfile = os.path.join(bsdir, '%sproc_%s.log' % ('reduced_' if handler else '', filename))
-            self.proc_files.append((filename, open(destfile, 'ab'), handler))
+            # The corresponding /proc files might not exist on the host.
+            # For example, /proc/diskstats is not available in virtualized
+            # environments like Linux-VServer. Silently skip collecting
+            # the data.
+            if os.path.exists(os.path.join('/proc', filename)):
+                # In practice, this class gets instantiated only once in
+                # the bitbake cooker process.  Therefore 'append' mode is
+                # not strictly necessary, but using it makes the class
+                # more robust should two processes ever write
+                # concurrently.
+                destfile = os.path.join(bsdir, '%sproc_%s.log' % ('reduced_' if handler else '', filename))
+                self.proc_files.append((filename, open(destfile, 'ab'), handler))
         self.monitor_disk = open(os.path.join(bsdir, 'monitor_disk.log'), 'ab')
         # Last time that we sampled /proc data resp. recorded disk monitoring data.
         self.last_proc = 0