Rails - Feb 2006 - SwitchTower 1.0.1, SwitchTower Extensions

SwitchTower is a utility that can execute commands in parallel on   
multiple servers. It allows you to define tasks, which can include  
commands that are executed on the servers. You can also define roles  
for your servers, and then specify that certain tasks apply only to  
certain roles.

    Manual: http://manuals.rubyonrails.org/read/book/17
    Project: http://rubyforge.org/projects/switchtower
    Install: gem install switchtower

SwitchTower 1.0.1, coming hard on the heels of 1.0.0, fixes the  
broken rakefile that was generated for rails applications. Nothing  
else was changed.

In addition to SwitchTower 1.0.1, I''d also like to announce  
SwitchTower Extensions 1.0.0, a collection of SwitchTower tasks and  
methods for use in your own SwitchTower recipes. There are two tasks  
provided by this library:

* watch_load. Just run "switchtower -r config/deploy -a watch_load"  
and you''ll see a display of the current load (1/5/15) for each of  
your servers. The display updates every 30 seconds.

* watch_requests. Run "switchtower -r config/deploy -a  
watch_requests" and you''ll see a display of the current requests/ 
second of each of your application servers, as harvested from your  
application log, in real-time.

Mostly, this library is provided as an example of how to write  
SwitchTower extensions, though some may find the tasks themselves  
useful. You can install SwitchTower extensions either by downloading  
from http://rubyforge.org/projects/switchtower, or by rubygems (gem  
install switchtower-ext). Once installed, you simply need to put  
"require ''switchtower/ext/monitor''" in your
deploy.rb and the tasks
will be available to you.

- Jamis

> In addition to SwitchTower 1.0.1, I''d also like to announce
SwitchTower
> Extensions 1.0.0, a collection of SwitchTower tasks and methods for use 
> in your own SwitchTower recipes. There are two tasks provided by this 
> library:
Ah, very nice. Totally minor, and I know these are just examples, but I 
found 3 small issues:

1. headers doesn''t properly handle a machine name that is exactly 1
char
less than the load width (it doesn''t pad, leaving staggered columns).

2. hostnames are truncated if they contain dashes -- i''m assuming the 
regex done is meant to grab the hostname from a fully-qualified name.

3. on debian (at least) uptime reports "load average: " and not
"averages: "

I can give you a patch if you''d like.

Amazing...

Good job Jamis!


Mikkel Bruun

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-- 
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On Feb 22, 2006, at 12:38 AM, Michael Schoen wrote:
>> In addition to SwitchTower 1.0.1, I''d also like to announce  
>> SwitchTower Extensions 1.0.0, a collection of SwitchTower tasks  
>> and methods for use in your own SwitchTower recipes. There are two  
>> tasks provided by this library:
>
> Ah, very nice. Totally minor, and I know these are just examples,  
> but I found 3 small issues:
>
> 1. headers doesn''t properly handle a machine name that is exactly
1
> char less than the load width (it doesn''t pad, leaving staggered  
> columns).
>
> 2. hostnames are truncated if they contain dashes -- i''m assuming
> the regex done is meant to grab the hostname from a fully-qualified  
> name.
>
> 3. on debian (at least) uptime reports "load average: " and not  
> "averages: "
>
> I can give you a patch if you''d like.
A patch would be wonderful! Thank-you, Michael.

- Jamis

Hi Jamis

One feature which I think would be nice to be included with
Switchtower, which I currently implement using my own tasks, is
provision for copying a ready to go database.yml file into the config
folder of the new release.

Because you would typically only check in an example database.yml
file, the way I''ve set things up is to create the database.yml file I
need and store it in the shared folder on the remote server. I''ve then
created a task that copies the database.yml file from shared into the
new release once its been checked out.

I''d submit a patch but to be honest I''m still a rake novice
and you
might be able to come up with something more elegant. Here is the code
I''m using if its of any use though:

desc "Copy configured database.yml to new current release"
task :copy_database_settings, :roles => :web do
	run "cp #{deploy_to}/shared/database.yml
#{release_path}/config/database.yml"
end

task :after_deploy, :roles => :web do
	copy_database_settings
end

The reason why I ask if it could be built in is because its typically
something you need to do with every project and its annoying to have
to copy the above into each new deploy file.

Great work with switchtower though, it truly is excellent.

On 2/22/06, Jamis Buck <jamis@37signals.com>
wrote:
> On Feb 22, 2006, at 12:38 AM, Michael Schoen wrote:
>
> >> In addition to SwitchTower 1.0.1, I''d also like to
announce
> >> SwitchTower Extensions 1.0.0, a collection of SwitchTower tasks
> >> and methods for use in your own SwitchTower recipes. There are two
> >> tasks provided by this library:
> >
> > Ah, very nice. Totally minor, and I know these are just examples,
> > but I found 3 small issues:
> >
> > 1. headers doesn''t properly handle a machine name that is
exactly 1
> > char less than the load width (it doesn''t pad, leaving
staggered
> > columns).
> >
> > 2. hostnames are truncated if they contain dashes -- i''m
assuming
> > the regex done is meant to grab the hostname from a fully-qualified
> > name.
> >
> > 3. on debian (at least) uptime reports "load average: " and
not
> > "averages: "
> >
> > I can give you a patch if you''d like.
>
> A patch would be wonderful! Thank-you, Michael.
>
> - Jamis
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

--
Cheers,
Luke Redpath
www.lukeredpath.co.uk

Luke,

I''ll definitely consider adding the copy_database_settings task to  
the standard tasks, but I wouldn''t make it executed by default  
(mostly because that''s not the way we use SwitchTower, and I suspect  
there are others that wouldn''t use that feature, either). Another  
option, though, is to package that up in a task library (http:// 
manuals.rubyonrails.org/read/chapter/122), such that it can be easily  
added to any of the projects you use.

- Jamis

On Feb 22, 2006, at 10:14 AM, Luke Redpath wrote:
> Hi Jamis
>
> One feature which I think would be nice to be included with
> Switchtower, which I currently implement using my own tasks, is
> provision for copying a ready to go database.yml file into the config
> folder of the new release.
>
> Because you would typically only check in an example database.yml
> file, the way I''ve set things up is to create the database.yml
file I
> need and store it in the shared folder on the remote server. I''ve
then
> created a task that copies the database.yml file from shared into the
> new release once its been checked out.
>
> I''d submit a patch but to be honest I''m still a rake
novice and you
> might be able to come up with something more elegant. Here is the code
> I''m using if its of any use though:
>
> desc "Copy configured database.yml to new current release"
> task :copy_database_settings, :roles => :web do
> 	run "cp #{deploy_to}/shared/database.yml #{release_path}/config/ 
> database.yml"
> end
>
> task :after_deploy, :roles => :web do
> 	copy_database_settings
> end
>
> The reason why I ask if it could be built in is because its typically
> something you need to do with every project and its annoying to have
> to copy the above into each new deploy file.
>
> Great work with switchtower though, it truly is excellent.
>
> On 2/22/06, Jamis Buck <jamis@37signals.com> wrote:
>> On Feb 22, 2006, at 12:38 AM, Michael Schoen wrote:
>>
>>>> In addition to SwitchTower 1.0.1, I''d also like to
announce
>>>> SwitchTower Extensions 1.0.0, a collection of SwitchTower tasks
>>>> and methods for use in your own SwitchTower recipes. There are
two
>>>> tasks provided by this library:
>>>
>>> Ah, very nice. Totally minor, and I know these are just examples,
>>> but I found 3 small issues:
>>>
>>> 1. headers doesn''t properly handle a machine name that is
exactly 1
>>> char less than the load width (it doesn''t pad, leaving
staggered
>>> columns).
>>>
>>> 2. hostnames are truncated if they contain dashes -- i''m
assuming
>>> the regex done is meant to grab the hostname from a fully-qualified
>>> name.
>>>
>>> 3. on debian (at least) uptime reports "load average: "
and not
>>> "averages: "
>>>
>>> I can give you a patch if you''d like.
>>
>> A patch would be wonderful! Thank-you, Michael.
>>
>> - Jamis
>>
>> _______________________________________________
>> Rails mailing list
>> Rails@lists.rubyonrails.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>
>
>
> --
> Cheers,
> Luke Redpath
> www.lukeredpath.co.uk
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

> A patch would be wonderful! Thank-you, Michael.
Let me know if the formatting below doesn''t work and I''ll
email you an
attachment. All changes are to monitor.rb:

39,40c39,41
<         padding = size - header.length - 1
<         print " ", "-" * padding if padding > 0
---
 >         padding = size - header.length
 >         print " " if padding > 0
 >         print "-" * (padding - 1) if padding > 1
50c51
<     names = servers.map { |s| s.match(/^(\w+)/)[1] }
---
 >     names = servers.map { |s| s.match(/^([^.]+)/)[1] }
57c58
<     parser = Proc.new { |text| text.match(/averages: 
(.*)$/)[1].split(/, /) }
---
 >     parser = Proc.new { |text| text.match(/average.*: 
(.*)$/)[1].split(/, /) }

Jamis -- it doesn''t look like this patches made it into the new 
Capistrano Extensions...

Michael Schoen wrote:
>> A patch would be wonderful! Thank-you, Michael.
> 
> Let me know if the formatting below doesn''t work and I''ll
email you an
> attachment. All changes are to monitor.rb:
> 
> 39,40c39,41
> <         padding = size - header.length - 1
> <         print " ", "-" * padding if padding > 0
> ---
>  >         padding = size - header.length
>  >         print " " if padding > 0
>  >         print "-" * (padding - 1) if padding > 1
> 50c51
> <     names = servers.map { |s| s.match(/^(\w+)/)[1] }
> ---
>  >     names = servers.map { |s| s.match(/^([^.]+)/)[1] }
> 57c58
> <     parser = Proc.new { |text| text.match(/averages: 
> (.*)$/)[1].split(/, /) }
> ---
>  >     parser = Proc.new { |text| text.match(/average.*: 
> (.*)$/)[1].split(/, /) }
> 
> 
> 
>

Michael,

My apologies for letting this patch languish for so long. It didn''t  
make it into 1.0.1 because at that point I was just trying to get the  
SwitchTower/Capistrano debacle taken care of and out of the way.

I''ve committed your patch, so it will be part of the next Capistrano  
Extensions release. Again, my apologies for not acting on this sooner.

- Jamis

On Feb 22, 2006, at 4:38 PM, Michael Schoen wrote:
>> A patch would be wonderful! Thank-you, Michael.
>
> Let me know if the formatting below doesn''t work and I''ll
email you
> an attachment. All changes are to monitor.rb:
>
> 39,40c39,41
> <         padding = size - header.length - 1
> <         print " ", "-" * padding if padding > 0
> ---
> >         padding = size - header.length
> >         print " " if padding > 0
> >         print "-" * (padding - 1) if padding > 1
> 50c51
> <     names = servers.map { |s| s.match(/^(\w+)/)[1] }
> ---
> >     names = servers.map { |s| s.match(/^([^.]+)/)[1] }
> 57c58
> <     parser = Proc.new { |text| text.match(/averages: (.*)$/) 
> [1].split(/, /) }
> ---
> >     parser = Proc.new { |text| text.match(/average.*: (.*)$/) 
> [1].split(/, /) }
>
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Luke, this is what I do to "copy" the current database to the current
release:

task :after_deploy do

  # create a link to database.yml
  run <<-CMD
    rm -rf #{current_path}/config/database.yml &&
    ln -nfs #{shared_path}/config/database.yml
#{current_path}/config/database.yml
  CMD

  restart
end

On 3/24/06, Jamis Buck <jamis@37signals.com>
wrote:
> Michael,
>
> My apologies for letting this patch languish for so long. It
didn''t
> make it into 1.0.1 because at that point I was just trying to get the
> SwitchTower/Capistrano debacle taken care of and out of the way.
>
> I''ve committed your patch, so it will be part of the next
Capistrano
> Extensions release. Again, my apologies for not acting on this sooner.
>
> - Jamis
>
> On Feb 22, 2006, at 4:38 PM, Michael Schoen wrote:
>
> >> A patch would be wonderful! Thank-you, Michael.
> >
> > Let me know if the formatting below doesn''t work and
I''ll email you
> > an attachment. All changes are to monitor.rb:
> >
> > 39,40c39,41
> > <         padding = size - header.length - 1
> > <         print " ", "-" * padding if padding
> 0
> > ---
> > >         padding = size - header.length
> > >         print " " if padding > 0
> > >         print "-" * (padding - 1) if padding > 1
> > 50c51
> > <     names = servers.map { |s| s.match(/^(\w+)/)[1] }
> > ---
> > >     names = servers.map { |s| s.match(/^([^.]+)/)[1] }
> > 57c58
> > <     parser = Proc.new { |text| text.match(/averages: (.*)$/)
> > [1].split(/, /) }
> > ---
> > >     parser = Proc.new { |text| text.match(/average.*: (.*)$/)
> > [1].split(/, /) }
> >
> >
> >
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>