bitbake: lib: Drop inotify support and replace with mtime checks

With the flush in serverlog() removed and a memory resident bitbake with a
60s timeout, the following could fail in strange ways:

rm bitbake-cookerdaemon.log
bitbake-layers add-layer ../meta-virtualization/
bitbake-layers add-layer ../meta-openembedded/meta-oe/
bitbake -m

specifically that it might error adding meta-oe with an error related to meta-virt.

This clearly shows that whilst bblayers.conf was modified, bitbake was not
recognising that. This would fit with the random autobuilder issues seen when
the serverlog flush() call was removed.

The issue appears to be that you have no way to "sync()" the inotify events with
the command stream coming over the socket. There is no way to know if there are
changes in the IO queue which bitbake needs to wait for before proceeding with
the next command.

I did experiment with os.sync() and fsync on the inotify fd, however nothing
addressed the issue. Since it is extremely important we have accurate cache data,
the only realistic thing to do is to switch to stat() calls and check mtime.

For bitbake commands, this is straightforward since we can revalidate the cache
upon new connections/commands. For tinfoil this is problematic and we need to
introduce and explict command "revalidateCaches" that the code can use to force
bitbake to re-check it's cache validity. I've exposed this through tinfoil with
a new "modified_files" function.

So, this patch:

a) drops inotify support within bitbake's cooker/server and switch to using mtime
b) requires a new function call in tinfoil when metadata has been modified

(Bitbake rev: da3ec3801bdb80180b3f1ac24edb27a698415ff7)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/bitbake/lib/bb/tinfoil.py b/bitbake/lib/bb/tinfoil.py
index 91fbf1b13e..2200caa54c 100644
--- a/bitbake/lib/bb/tinfoil.py
+++ b/bitbake/lib/bb/tinfoil.py
@@ -449,6 +449,12 @@ class Tinfoil:
         self.run_actions(config_params)
         self.recipes_parsed = True
 
+    def modified_files(self):
+        """
+        Notify the server it needs to revalidate it's caches since the client has modified files
+        """
+        self.run_command("revalidateCaches")
+
     def run_command(self, command, *params, handle_events=True):
         """
         Run a command on the server (as implemented in bb.command).