[ovs-dev] [PATCH 1/2] travis: Retry kernel download on 503 first byte timeout.

[Ilya Maximets]

On 21.05.2019 2:13, Ben Pfaff wrote:
> On Mon, May 20, 2019 at 04:29:38PM +0300, Ilya Maximets wrote:
>> Sometimes it takes to long for CDN to reply in case of downloading
>> of not frequently used kernels.
>> For example, even on my local PC it fails to download linux-4.19.29
>> at the first try:
>>
>>   $ wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.19.29.tar.xz
>>   Resolving cdn.kernel.org (cdn.kernel.org)... 151.101.1.176
>>   Connecting to cdn.kernel.org |151.101.1.176|:443... connected.
>>   HTTP request sent, awaiting response... 503 first byte timeout
>>
>> Example from TravisCI:
>>   https://travis-ci.org/openvswitch/ovs/jobs/530247589
>>
>> It seems that CDN downloads the tar for that time to the nearby
>> server and instant retry usually succeeds immediately.
>>
>> 503 is not a "fatal error" for wget and, unfortunately, wget on
>> TravisCI is too old and we can't just use "--retry-on-http-error=503"
>> to avoid failures in this case. So, let's just retry unconditionally.
>> Fallback to the direct download if CDN fails twice.
>>
>> Fixes: ae6e4f12fcab ("travis: Speed up linux kernel downloads.")
>> Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
>> ---
>>  .travis/linux-build.sh | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/.travis/linux-build.sh b/.travis/linux-build.sh
>> index d869713f7..c8c9748ac 100755
>> --- a/.travis/linux-build.sh
>> +++ b/.travis/linux-build.sh
>> @@ -19,7 +19,11 @@ function install_kernel()
>>          PREFIX="v2.6/longterm/v2.6.32"
>>      fi
>>  
>> -    wget https://cdn.kernel.org/pub/linux/kernel/${PREFIX}/linux-${1}.tar.xz
>> +    cdn="https://cdn."
>> +    direct="https://www."
>> +    link="kernel.org/pub/linux/kernel/${PREFIX}/linux-${1}.tar.xz"
>> +    # Download kernel sources. Try direct link on CDN failure.
>> +    wget ${cdn}${link} || wget ${cdn}${link} || wget ${direct}${link}
>>      tar xvf linux-${1}.tar.xz > /dev/null
>>      cd linux-${1}
>>      make allmodconfig
> 
> Acked-by: Ben Pfaff <blp at ovn.org>
> 
> Since this is a bash-only script, the bash hacker in me wants to write
> it something like:
> 
> url=https://cdn.kernel.org/pub/linux/kernel/${PREFIX}/linux-${1}.tar.xz
> wget $url || wget $url || wget ${url/cdn/www}
> 
> Maybe that is too clever though.

I like your version. It's shorter and doesn't require additional variables.
I updated the patch with that suggestion and pushed to master. Thanks.

Best regards, Ilya Maximets.