Re: Location limits on development, staging and production environments

[H <agents@meddatainc.com>]

On 01/30/2018 03:48 PM, H wrote:
> On 01/29/2018 10:02 PM, Bryan Turner wrote:
>> On Mon, Jan 29, 2018 at 11:08 AM, H <agents@meddatainc.com> wrote:
>>> I am a newcomer to git looking to set up a web development environment where individual computers are used for development, the development.git, staging.git and production.git repositories are stored on an external server reachable by password-less ssh and the staging and production websites are on yet another server, also reachable by password-less ssh from the git-server (and the development machines).
>>>
>>> Locating the three git repositories on an external server works fine but I have not been able to have the staging and production deployment files on another server. I believe this is what is referred by GIT_WORK_TREE and based on what I found on the web I created a post-receive hook of staging.git with the two lines:
>>>
>>> #!/bin/sh
>>> GIT_WORK_TREE=user@1.2.3.4:/var/www/html/dev.whatever git checkout -f master
>>>
>>> I believe this should deploy the files from the development work tree.
>>>
>>> The above, however, fails. Should it work? I am running git 1.7.1 on CentOS 6.
>> No, I wouldn't expect that to work. GIT_WORK_TREE is not remote-aware
>> in that way. It's expected to be a normal-ish filesystem path.
>>
>> Based on your description, and the hook you've written, it seems like
>> your intention is for the source to automatically be fetched and
>> checked out on the staging environment after each push. (This is
>> dangerous, and likely _not_ what you actually want, but I'll get to
>> that in a moment.)
>>
>> One option would be to setup something like NFS, so the git-server can
>> mount the filesystems from the staging and production nodes.
>>
>> A different, likely better, option would be to have the post-receive
>> script on the git-server use straight ssh to trigger a checkout script
>> on the staging server, e.g.:
>> #!/bin/sh
>> ssh example@staging-server -C /opt/deploy-staging.sh
>>
>> Your deploy-staging script would then do something like:
>> #!/bin/sh
>> GIT_WORK_TREE=/var/www/html/dev.whatever git pull origin
>>
>> That said, though, having such a simple script is dangerous because
>> Git is fully capable of having receiving multiple pushes concurrently,
>> and they can all succeed as long as they're updating different
>> branches. Since your script isn't considering what branches were
>> changed by the push, it could end up triggering simultaneous git
>> processes on the staging server all attempting to deploy concurrently.
>>
>> The stdin for the post-receive hook receives details about which refs
>> were changed, and you'll likely want to update your script to parse
>> stdin and only try to deploy staging if a specific, relevant branch
>> (master in your example) has changed.
>>
>> Lastly, I'll note that using post-receive will make the pushing
>> (remote) user wait while the staging server is deployed. If that
>> process is likely to take very long, you might want to decouple the
>> two somehow.
>>
>> Hope this helps!
> I should perhaps also have mentioned that although I am the only developer, I may use different computers to develop on. IOW, there should not be any conflict due to code being pushed by multiple developers.
>
> Let's see if I understand this correctly:
>
> - Unless NFS is used, the git archive and the deployment of the website code in this case should reside on the same computer.
>
> - The combination of the checkout script and the deploy-staging script should work provided not multiple updates to the same branch are pushed at the same time.
>
> I will try this later today but any other hints or suggestions you may have would be greatly appreciated!
>
I modified post-receive in the hook directory of the staging git archive on server 1 as per your first example and created the deploy-staging.sh script on server 2 where the staging website resides in /var/www/html/dev.whatever (as well as the live website in /var/www/html/whatever. However, when trying out the deploy-staging.sh script, it fails with the error message "...not a git repository...". I do have git on server 2 but what else would I need to set up to run this successfully? Note that the git repository is on server 1 and I am deploying to server 2.

Thanks!