Manage ECS scheduled tasks like Whenever gem.
Add this line to your application's Gemfile:
gem 'elastic_whenever'
And then execute:
$ bundle
Or install it yourself as:
$ gem install elastic_whenever
You can use it almost like Whenever. However, please be aware that you must specify an identifier.
$ elastic_whenever --help
Usage: elastic_whenever [options]
-i, --update identifier Clear and create scheduled tasks by schedule file
-c, --clear identifier Clear scheduled tasks
-l, --list identifier List scheduled tasks
-s, --set variables Example: --set 'environment=staging'
--cluster cluster ECS cluster to run tasks
--task-definition task_definition
Task definition name, If omit a revision, use the latest revision of the family automatically. Example: --task-deifinition oneoff-application:2
--container container Container name defined in the task definition
--launch-type launch_type Launch type. EC2 or FARGATE. Defualt: EC2
--assign-public-ip Assign a public IP. Default: DISABLED (FARGATE only)
--security-groups groups Example: --security-groups 'sg-2c503655,sg-72f0cb0a' (FARGATE only)
--subnets subnets Example: --subnets 'subnet-4973d63f,subnet-45827d1d' (FARGATE only)
--platform-version version Optionally specify the platform version. Default: LATEST (FARGATE only)
-f, --file schedule_file Default: config/schedule.rb
--iam-role name IAM role name used by CloudWatch Events. Default: ecsEventsRole
--rule-state state The state of the CloudWatch Events Rule (ENABLED or DISABLED), default: ENABLED
--profile profile_name AWS shared profile name
--access-key aws_access_key_id
AWS access key ID
--secret-key aws_secret_access_key
AWS secret access key
--region region AWS region
-v, --version Print version
-V, --verbose Run rake jobs without --silent
NOTE: Currently, Elastic Whenever supports the Whenever syntax partially. We strongly encourage to use dry-run mode for verifying tasks to be created.
$ elastic_whenever --cluster ecs-test --task-definition example:2 --container cron
cron(0 3 * * ? *) ecs-test example:2 cron bundle exec rake hoge:run
## [message] Above is your schedule file converted to scheduled tasks; your scheduled tasks was not updated.
## [message] Run `elastic_whenever --help' for more options.
Elastic Whenever supports setting variables via the --set
option as Whenever does.
Example:
elastic_whenever --set 'environment=staging&some_var=foo'
if @environment == 'staging'
every '0 1 * * *' do
rake 'some_task_on_staging'
end
elsif @some_var == 'foo'
every '0 10 * * *' do
rake 'some_task'
end
end
Especially, @environment
defaults to "production"
.
Elastic Whenever creates CloudWatch Events as many as every
block. Each event has as many targets as there are commands in the block.
every '0 0 * * *' do # scheduled task (identifier_68237a3b152a6c44359e1cf5cd8e7cf0def303d7)
rake "hoge:run" # target for `identifier_68237a3b152a6c44359e1cf5cd8e7cf0def303d7`
command "awesome" # target for `identifier_68237a3b152a6c44359e1cf5cd8e7cf0def303d7`
end
The scheduled task's name is a digest value calculated from an identifier, commands, and so on.
NOTE: You should not use the same identifier across different clusters because CloudWatch Events rule names are unique across all clusters.
Whenever supports custom job type with job_type
method, but Elastic Whenever doesn't support it.
# [warn] Skipping unsupported method: job_type
job_type :awesome, '/usr/local/bin/awesome :task :fun_level'
Whenever supports environment variables with env
method, but Elastic Whenever doesn't support it.
You should use task definitions to set environment variables.
# [warn] Skipping unsupported method: env
env "VERSION", "v1"
Whenever has a template to describe as cron, but Elastic Whenever doesn't have the template.
Therefore, :job_template
option is ignored.
set :job_template, "/bin/zsh -l -c ':job'" # ignored
Elastic Whenever processes frequency passed to every
block almost like Whenever.
# Whenever
# 0 15 * * * /bin/bash -l -c 'cd /home/user/app && RAILS_ENV=production bundle exec rake hoge:run --silent'
#
# Elastic Whenever
# cron(0 15 * * ? *) ecs-test myapp:2 web bundle exec rake hoge:run --silent
#
every :day, at: "3:00" do
rake "hoge:run"
end
# Whenever
# 0,10,20,30,40,50 * * * * /bin/bash -l -c 'awesome'
#
# Elastic Whenever
# cron(0,10,20,30,40,50 * * * ? *) ecs-test myapp:2 web awesome
#
every 10.minutes do
command "awesome"
end
However, handling of the day of week is partially different because it follows scheduled expression.
# Whenever
# 0 0 * * 1 /bin/bash -l -c 'awesome'
#
# Elastic Whenever
# cron(0 0 ? * 2 *) ecs-test myapp:2 web awesome
#
every :monday do
command "awesome"
end
Therefore, cron syntax is converted to scheduled expression like the following:
# cron(0 0 ? * 2 *) ecs-test myapp:2 web awesome
every "0 0 * * 1" do
command "awesome"
end
Absolutely, you can also write scheduled expression.
# cron(0 0 ? * 2 *) ecs-test myapp:2 web awesome
every "0 0 ? * 2 *" do
command "awesome"
end
Whenever supports :reboot
as a cron option, but Elastic Whenever doesn't support it.
# [warn] `reboot` is not supported option. Ignore this task.
every :reboot do
rake "hoge:run"
end
Whenever checks if the application uses bundler and automatically adds a prefix to commands. However, Elastic Whenever always adds a prefix on a premise that the application is using bundler.
# Whenever
# With bundler -> bundle exec rake hoge:run
# Without bundler -> rake hoge:run
#
# Elastic Whenever
# bundle exec rake hoge:run
#
rake "hoge:run"
If you don't want to add the prefix, set bundle_command
to empty as follows:
set :bundle_command, ""
Whenever supports runner
job with old Rails versions, but Elastic Whenever supports Rails 4 and above only.
# Whenever
# Before them -> script/runner Hoge.run
# Rails 3 -> script/rails runner Hoge.run
# Rails 4 -> bin/rails runner Hoge.run
#
# Elastic Whenever
# bin/rails runner Hoge.run
#
runner "Hoge.run"
After checking out the repo, run bin/setup
to install dependencies. Then, run rake spec
to run the tests. You can also run bin/console
for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install
. To release a new version, update the version number in version.rb
, and then run bundle exec rake release
, which will create a git tag for the version, push git commits and tags, and push the .gem
file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/wata727/elastic_whenever.