gem install fail_fast
Insert this code early in your program starting sequence :
require 'fail_fast'
FailFast().check do
is_on_path '_why'
fail "I don't work on Sunday" if 0 == Time.now.wday
end
If _why can't be found :
-
the application will exit immediately and
-
you will see this report :
+------------------------------------------------------------------------------------------ | FAIL_FAST error : precondition(s) not met. +------------------------------------------------------------------------------------------ | _why could not be found on the path +------------------------------------------------------------------------------------------
Early in your project boot sequence insert this code :
require 'fail_fast'
FailFast("path/to/database.yml").check do
has_active_record_db_for 'production', :message => 'The main DB cannot be reached :'
end
remark : the :message part is always optional.
If the DB connection fails,
-
the application will exit immediately and
-
you will see this report :
+------------------------------------------------------------------------------------------
FAIL_FAST error : precondition(s) not met in file : "path/to/database.yml" +------------------------------------------------------------------------------------------ error key value +------------------------------------------------------------------------------------------ The main DB cannot be reached : * active_record_db_connection_error production Unknown database 'a_db' +------------------------------------------------------------------------------------------
Remark : check
will call exit(1)
at the end of the first block with an error.
If you want to collect and report all the errors before exiting, use check_now.but_fail_later
(see Example 2 below).
require 'fail_fast'
FailFast('database.yml').check_now.but_fail_later do
has_active_record_db_for 'production'
end
FailFast('database.mongo.yml').check_now.but_fail_later do
has_mongoDB_for Rails.env
end
FailFast('path_to/config.yml', prefix=Rails.env).check_now.but_fail_later do
has_values_for 'author/fname', 'author/lname'
has_email_for 'newsletter/to_address'
only_if Rails.env.production? do
has_url_for 'bug_tracker/url', :reachable => true
end
directory_exists_for '/tmp', :message => 'the log '
file_exists_for 'public/nda.pdf'
skip_if Rails.env.development? do
fail "I don't work on Sunday" if 0 == Time.now.wday
end
end
FailFast.fail_now # exit it an error was detected in any of the 3 blocks above.
If it fails, you'll get a report like this :
+------------------------------------------------------------------------------------------
| FAIL_FAST error : precondition(s) not met in
| -----------------
| file : "path/to/database.yml"
| keys prefix : (none)
+------------------------------------------------------------------------------------------
| error key value
+------------------------------------------------------------------------------------------
| * active_record_db_connection_error production Unknown database 'a_db'
+------------------------------------------------------------------------------------------
+------------------------------------------------------------------------------------------
| FAIL_FAST error : precondition(s) not met in
| -----------------
| file : "./spec/_/fixtures/simple.yml"
| keys prefix : none
+------------------------------------------------------------------------------------------
| error key value
+------------------------------------------------------------------------------------------
| * missing_value first_keyNOT
| * missing_value last_keyNOT
| * missing_value number_sixNOT
| * missing_value testNOT/mongoDB/database
| * value_does_not_match last_key dernier
| * not_an_email test/host localhost
| * not_a_url test/host localhost
| * url_not_reachable test/url_not_reachable http://xxx.zzz
| * directory_not_found /foobarbaz
| * directory_not_found test/a_file ./spec/_/fixtures/simple.yml
| * file_not_found /tmp/foo/bar/??nOTaFile
| * file_not_found test/a_directory ./spec/_/fixtures
| * mongoDB_server_not_found 10.0.0.123
| * mongoDB_server_not_found test/mongoDB localhost
| * mongoDB_db_not_found not_a_known_db
| * mongoDB_db_not_found test/unknown_mongoDB_db unknown_mongoDB_db
| * active_record_db_connection_error Unknown database 'some-db'
| * active_record_db_connection_error db_connection Unknown database 'a_db'
| * fail a custom failure message
+------------------------------------------------------------------------------------------
FailFast().check_now.but_fail_later do
directory_exists_for '/cache' # default error handling/message
unless directory_exists_for '/log' # custom error handling
puts "The /log directory is missing" # ...
puts "create it with $ mkdir /log" # ...
end # ...
end
FailFast.fail_now # exit it an error was detected in any of the 3 blocks above.
... # code like in the cases above.
if FailFast.failed?
puts "Cannot start the application due to the problems mentioned above."
puts "You can skip those test with the SKIP_FAIL_FAST environment variable"
FailFast.fail_now unless 'true'==ENV['SKIP_FAIL_FAST']
end
Example 5a : send errors report to Hoptoad (http://hoptoadapp.com)
FailFast().check do
... # errors only reported to stdout
end
...
require 'hoptoad_notifier'
FailFast.report_to :hoptoad => '<your-api-token>' # <- add this in your FF script
...
FailFast().check do
... # errors are (also) reported to your Hoptoad account
end
Example 5b : send errors report to Exceptional (http://getexceptional.com)
FailFast().check do
... # errors only reported to stdout
end
...
require 'exceptional' # <- add this in your FF script
FailFast.report_to :exceptional => '<your-api-token>' # <- add this in your FF script
...
FailFast().check do
... # errors are (also) reported to your Hoptoad account
end
Remark : Error reporters
- :stdout is the default (cannot be disabled)
- you can combine the error reporters (ex: stdout + :hoptoad + :exceptional)
This gem DSL lets you write preconditions-scripts that you run early in the boot sequence of an application. An exception is raised if one or more tests fail, and you get a detailled report of all the problems encountered.
Some rules are based on the contents of configuration files (database.yml, config.yml, etc...) :
- can a database connnection be established?
- is the mongoDB server active?
- is there an :application_name value in config.yml, and does it match a regexp pattern?
- is the value of :info_email_ a valid email?
- is the value of :sponspor_link a valid url, and is the site up?
You can also add custom rules, not related to any config files :
- is there a /tmp, or an public/upload directory on the server?
- can the server access http://google.com?
- is there a public/nda_pdf file?
- etc..
fail "I don't work on Sunday" if (0 == Time.now.wday)
directory_exists '/tmp'
file_exists '/Users/me/.bash_profile'
has_mongoDB 'localhost', 'db_app_1'
has_active_record_db :host => 'dbserv', :adapter => 'mysql', :database => 'db'
####Test values linked to a key :
presence :
has_value_for :application_name
has_values_for 'author/fname', 'author/lname'
contents <-> a regexp or pattern :
has_value_for 'level', /(alpha|beta|production)/
has_url_for 'bug_tracker/url'
has_email_for 'newsletter/to_address'
-
customize it
nda_file = value_of(:nda_file) fail 'NDA is too old' if (Time.now - File.mtime(nda_file)) > (24 * 60 * 60) * 365
Test the file system and .. :
directory_exists '/home/ci/uploads'
file_exists '/home/ci/config/secret.key'
# the keyed version :
directory_exists_for 'assets-upload_dir'
file_exists_for 'assets-nda_pdf_file'
is_on_path 'jruby' # fail if jruby cannot be found
is_on_path_for :ruby_engine
Test external services :
# is a webserver up ?
has_url_for 'bug_tracker/url', :reachable => true
has_url_for 'bug_tracker/url', :reachable => true, :may_add_trailing_slash => true
# can we connect to a mongoDB db/server :
has_mongoDB_for 'test/mongoDB'
has_mongoDB_for 'test/unknown_mongoDB_db', :check_database => false
# can we connect to a SQL db :
has_active_record_db_for 'production/db_connection'
Misc :
fail "I don't work on Sunday" if 0 == Time.now.wday
Control commands :
skip_if <condition> do .. end
only_if <condition> do .. end