A collection of useful middleware for exposing information about deployed Rack applications. Efficiency 2.0 uses this to track distributed transactions across its Ruby-based service oriented architecture.
- Adds a
X-Served-Byheader with the hostname of the server that processed the request.
- Adds a
X-Transactionheader with a unique ID for the web request.
- Adds a
X-Revisionheader with the running Git revision.
- Adds an endpoint of
/system/revisionfor easily checking the running revision. This can be leveraged in a post-deployment sanity check to ensure the application servers restarted properly.
Add to your
gem "e20_ops_middleware", :require => "e20/ops/middleware"
Install the gem:
$ bundle install
config/initializers/ops_middleware.rb with the following:
Rails.application.middleware.with_options :logger => Rails.logger do |m| m.use E20::Ops::Middleware::RevisionMiddleware m.use E20::Ops::Middleware::HostnameMiddleware m.use E20::Ops::Middleware::TransactionIdMiddleware end
use E20::Ops::Middleware::RevisionMiddleware use E20::Ops::Middleware::HostnameMiddleware use E20::Ops::Middleware::TransactionIdMiddleware
The information exposed by the middleware can be viewed manually with
and will also be logged to the provided logger (or STDOUT). Additionally,
we've found it useful to log this information when receiving responses from
REST web services.
Revisions can be queried directly by using the
$ curl http://instance/system/revision fe09f24b4a927b6eab5db66b6a89fe960e2ff03b
The current revision will be passed as an HTTP header for other requests:
$ curl -I http://instance/ HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 Content-Length: 3304 X-Revision: fe09f24b4a927b6eab5db66b6a89fe960e2ff03b
The current revision will also be logged upon application start:
$ grep RevisionMiddleware log/production.log [E20::Ops::Middleware::RevisionMiddleware] Running: fe09f24b4a927b6eab5db66b6a89fe960e2ff03b
The hostname of the system that processed the request will be passed as an HTTP header:
$ curl -I http://instance/ HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 Content-Length: 3304 X-Served-By: fulton
The hostname will also be logged upon application start:
$ grep HostnameMiddleware log/production.log [E20::Ops::Middleware::HostnameMiddleware] Running on: fulton
A transaction ID will be logged for each incoming request:
$ grep TransactionIdMiddleware log/production.log [E20::Ops::Middleware::TransactionIdMiddleware] Transaction ID: 111d3180-91f4-012d-ce1a-549a20d01d99
The transaction ID will also be passed as an HTTP header:
$ curl -I http://instance/ HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 Content-Length: 3304 X-Transaction: 111d3180-91f4-012d-ce1a-549a20d01d99
Thanks to Efficiency 2.0 (http://efficiency20.com) for sponsoring development of this gem.
To run the tests:
$ bundle install $ rake
(The MIT License)
Copyright © 2010 Efficiency 2.0, LLC
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.