Packaging protobuf-c for EL5

How boring a title that is!  Okay, we're RPMing up Protobuf-c - a c binding for the protobuf kit from Google - for EL5.  We need it to do something far more interesting later -- so these are the giants whose shoulders we stand upon.

I cheated;  let's be honest about that, and just how much I cheat to make my life easier.  It's a lot!  In this case, I stole the protobuf-c RPM as built in RHbz593559 for EL6, and which is supposed to be started for EL5 but hasn't dropped yet.  So we'll just finish that port.

1. Go get it:
   wget http://download.fedoraproject.org/pub/epel/6/SRPMS/protobuf-c-0.15-2.el6.src.rpm
2. Unpacking it is harder because of a strange change to the package format, where they seem to ignore compatibility.  So we need to do an rpm2cpio|cpio instead of a trivial rpm-i .  It's no big deal, but watch for it:
   

   rpm2cpio protobuf-c-0.15-2.el6.src.rpm | cpio -idumv

3. Because the EL6 one has problems, we need to patch around those, but they're trivial;  it's surprising that we see this in what should be a quality product.  I worry about just how many people have this kind of blinders on.
   

   @@ -10,6 +10,7 @@

    Source1:        http://protobuf-c.googlecode.com/svn/tags/%{version}/LICENSE
   
    BuildRequires:  protobuf-devel
   +BuildRoot:     %{_tmppath}/%{name}-root
   
    %description
    Protocol Buffers are a way of encoding structured data in an efficient yet@@ -41,9 +41,13 @@

    make check
   
    %install
   +[ "$RPM_BUILD_ROOT" != "/" ] && rm -rf $RPM_BUILD_ROOT
    make install DESTDIR=$RPM_BUILD_ROOT
    rm -f $RPM_BUILD_ROOT/%{_libdir}/libprotobuf-c.la
   
   +%clean
   +[ "$RPM_BUILD_ROOT" != "/" ] && rm -rf $RPM_BUILD_ROOT
   +
    %post -p /sbin/ldconfig
    %postun -p /sbin/ldconfig

4. now build:
   

   rpmbuild -ba protobuf-c.spec

And that's kinda it.  Can you see how simple a package-port this is?

Can you see how simple code-compatibility things we learned in first-year CompSci are being ignored here to our detriment?  This is so disappointing, and it wouldn't be a problem if I haven't had this very same conversation with someone in a position to fix it.

Diffing Configs After an RPM install

Some daemon not starting?  Think you may have mucked with the config and you don't know how?  Let's talk about stashing your configs in an SCM, you lamer, or maybe doing a backup every month or so?  (ha, gotcha) For now, let's find out what you've done.

[root@gator ~]# mkdir /tmp/bz75819
[root@gator ~]# yumdownloader --destdir !$ `rpm -qf --qf "%{name}\n" /etc/httpd/conf/httpd.conf`
yumdownloader --destdir /tmp/bz75819 `rpm -qf --qf "%{name}\n" /etc/httpd/conf/httpd.conf`
[root@gator ~]# rpm2cpio /tmp/bz75819/*.rpm | cpio -tv | grep /etc/httpd/conf/httpd.conf
6573 blocks
-rw-r--r--   1 root     root        33726 Oct 20 14:05 ./etc/httpd/conf/httpd.conf
[root@gator ~]# rpm2cpio /tmp/bz75819/*.rpm | cpio -i --to-stdout */etc/httpd/conf/httpd.conf | diff -u - /etc/httpd/conf/httpd.conf
6573 blocks
--- -   2012-03-03 16:05:07.411845000 -0800
+++ /etc/httpd/conf/httpd.conf  2012-03-03 16:05:01.000000000 -0800
@@ -131,7 +131,7 @@
 # prevent Apache from glomming onto all bound IP addresses (0.0.0.0)
 #
 #Listen 12.34.56.78:80
-Listen 80
+#Listen 80

 #
 # Dynamic Shared Object (DSO) Support

So that's what you've done.  Yeah, it looks contrived, but I saw that this week.  So when I see it again this week, I know what to do.

Have you ever needed to find out just what you've changed in a config since a package has been installed?