179 lines
9.6 KiB
Ruby
179 lines
9.6 KiB
Ruby
require 'concurrent/future'
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require 'concurrent/timer_task'
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class DockerContainerPool
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# Always use a semaphore when dealing with write access to `@containers` or `@all_containers` or read access if that involves creating a new container
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# Some methods have the `bypass_semaphore` flag which should be rarely used. It was introduced when adding the semaphore to the `replace_broken_container` method.
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# When `replace_broken_container` was extended to check the total amount of containers first, the `bypass_semaphore` flag was also added to `get_container` and
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# back to `replace_broken_container`. When the semaphore is not released, no container operations can be done!
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# Furthermore, the semaphore is used when killing a container in the DockerClient.
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@semaphore = Concurrent::Semaphore.new(1)
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@containers = Concurrent::Hash[ExecutionEnvironment.all.map { |execution_environment| [execution_environment.id, Concurrent::Array.new] }]
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#as containers are not containing containers in use
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@all_containers = Concurrent::Hash[ExecutionEnvironment.all.map { |execution_environment| [execution_environment.id, Concurrent::Array.new] }]
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def self.clean_up
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Rails.logger.info('Container Pool is now performing a cleanup. ')
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@refill_task.try(:shutdown)
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@all_containers.values.each do |containers|
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DockerClient.destroy_container(containers.shift) until containers.empty?
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end
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end
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def self.config
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#TODO: Why erb?
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@config ||= CodeOcean::Config.new(:docker).read(erb: true)[:pool]
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end
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def self.containers
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@containers
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end
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def self.all_containers
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@all_containers
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end
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def self.acquire_semaphore
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return
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Rails.logger.info("Semaphore - Acquire: Trying " + @semaphore.inspect.to_s + " for " + caller_locations(1, 1)[0].label)
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got_semaphore = @semaphore.try_acquire(1, 20)
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if got_semaphore
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Rails.logger.info("Semaphore - Acquire: Got " + @semaphore.inspect.to_s + " for " + caller_locations(1, 1)[0].label)
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else
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Rails.logger.error("Semaphore - Acquire: Failed " + @semaphore.inspect.to_s + " for " + caller_locations(1, 1)[0].label)
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end
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end
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def self.release_semaphore
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return
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Rails.logger.info("Semaphore - Release: Trying " + @semaphore.inspect.to_s + " for " + caller_locations(1, 1)[0].label)
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if @semaphore.available_permits < 1
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@semaphore.release
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Rails.logger.info("Semaphore - Release: Done " + @semaphore.inspect.to_s + " for " + caller_locations(1, 1)[0].label)
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else
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Rails.logger.info("Semaphore - Release: Failed " + @semaphore.inspect.to_s + " for " + caller_locations(1, 1)[0].label)
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end
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end
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def self.remove_from_all_containers(container, execution_environment)
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if @containers[execution_environment.id].include?(container)
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@containers[execution_environment.id].delete(container)
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Rails.logger.debug('Removed container ' + container.to_s + ' from available_pool for execution environment ' + execution_environment.to_s + '. Remaining containers in available_pool ' + @containers[execution_environment.id].size.to_s)
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end
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@all_containers[execution_environment.id].delete(container)
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Rails.logger.debug('Removed container ' + container.to_s + ' from all_pool for execution environment ' + execution_environment.to_s + '. Remaining containers in all_pool ' + @all_containers[execution_environment.id].size.to_s)
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end
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def self.add_to_all_containers(container, execution_environment)
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@all_containers[execution_environment.id].push(container)
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if !@containers[execution_environment.id].include?(container)
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@containers[execution_environment.id].push(container)
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#Rails.logger.debug('Added container ' + container.to_s + ' to all_pool for execution environment ' + execution_environment.to_s + '. Containers in all_pool: ' + @all_containers[execution_environment.id].size.to_s)
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else
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Rails.logger.error('failed trying to add existing container ' + container.to_s + ' to execution_environment ' + execution_environment.to_s)
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end
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end
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def self.create_container(execution_environment)
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Rails.logger.info('trying to create container for execution environment: ' + execution_environment.to_s)
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container = DockerClient.create_container(execution_environment)
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container.status = 'available' # FIXME: String vs Symbol usage?
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#Rails.logger.debug('created container ' + container.to_s + ' for execution environment ' + execution_environment.to_s)
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container
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end
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def self.return_container(container, execution_environment)
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container.status = 'available' # FIXME: String vs Symbol usage?
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if @containers[execution_environment.id] && !@containers[execution_environment.id].include?(container)
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@containers[execution_environment.id].push(container)
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else
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Rails.logger.error('trying to return existing container ' + container.to_s + ' to execution_environment ' + execution_environment.to_s)
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end
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end
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def self.get_container(execution_environment, bypass_semaphore: false)
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# if pooling is active, do pooling, otherwise just create an container and return it
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if config[:active]
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container = @containers[execution_environment.id].try(:shift) || nil
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Rails.logger.debug('get_container fetched container ' + container.to_s + ' for execution environment ' + execution_environment.to_s)
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# just access and the following if we got a container. Otherwise, the execution_environment might be just created and not fully exist yet.
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if(container)
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begin
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# check whether the container is running. exited containers go to the else part.
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# Dead containers raise a NotFOundError on the container.json call. This is handled in the rescue block.
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if(container.json['State']['Running'])
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Rails.logger.debug('get_container remaining avail. containers: ' + @containers[execution_environment.id].size.to_s)
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Rails.logger.debug('get_container all container count: ' + @all_containers[execution_environment.id].size.to_s)
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else
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Rails.logger.error('docker_container_pool.get_container retrieved a container not running. Container will be removed from list: ' + container.to_s)
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#TODO: check in which state the container actually is and treat it accordingly (dead,... => destroy?)
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container = replace_broken_container(container, execution_environment, bypass_semaphore: bypass_semaphore)
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end
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rescue Docker::Error::NotFoundError => error
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Rails.logger.error('docker_container_pool.get_container rescued from Docker::Error::NotFoundError. Most likely, the container is not there any longer. Removing faulty entry from list: ' + container.to_s)
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container = replace_broken_container(container, execution_environment, bypass_semaphore: bypass_semaphore)
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end
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end
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# returning nil is no problem. then the pool is just depleted.
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container
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else
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create_container(execution_environment)
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end
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end
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def self.replace_broken_container(container, execution_environment, bypass_semaphore: false)
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# See note at the top for `bypass_semaphore`
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acquire_semaphore unless bypass_semaphore
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remove_from_all_containers(container, execution_environment)
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missing_counter_count = execution_environment.pool_size - @all_containers[execution_environment.id].length
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if missing_counter_count > 0
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Rails.logger.error('replace_broken_container: Creating a new container and returning that.')
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new_container = create_container(execution_environment)
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DockerContainerPool.add_to_all_containers(new_container, execution_environment)
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else
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Rails.logger.error('Broken container removed for ' + execution_environment.to_s + ' but not creating a new one. Currently, ' + missing_counter_count.abs + ' more containers than the configured pool size are available.')
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new_container = get_container(execution_environment, bypass_semaphore: true)
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end
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release_semaphore unless bypass_semaphore
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new_container
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end
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def self.quantities
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@containers.map { |key, value| [key, value.length] }.to_h
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end
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def self.refill
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ExecutionEnvironment.where('pool_size > 0').order(pool_size: :desc).each do |execution_environment|
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if config[:refill][:async]
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Concurrent::Future.execute { refill_for_execution_environment(execution_environment) }
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else
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refill_for_execution_environment(execution_environment)
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end
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end
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end
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def self.refill_for_execution_environment(execution_environment)
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acquire_semaphore
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refill_count = [execution_environment.pool_size - @all_containers[execution_environment.id].length, config[:refill][:batch_size]].min
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if refill_count > 0
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Rails.logger.info('Adding ' + refill_count.to_s + ' containers for execution_environment ' + execution_environment.name )
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multiple_containers = refill_count.times.map { create_container(execution_environment) }
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#Rails.logger.info('Created containers: ' + multiple_containers.to_s )
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@containers[execution_environment.id].concat(multiple_containers)
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@all_containers[execution_environment.id].concat(multiple_containers)
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#Rails.logger.debug('@containers for ' + execution_environment.name.to_s + ' (' + @containers.object_id.to_s + ') has the following content: '+ @containers[execution_environment.id].to_s)
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#Rails.logger.debug('@all_containers for ' + execution_environment.name.to_s + ' (' + @all_containers.object_id.to_s + ') has the following content: ' + @all_containers[execution_environment.id].to_s)
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end
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release_semaphore
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end
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def self.start_refill_task
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@refill_task = Concurrent::TimerTask.new(execution_interval: config[:refill][:interval], run_now: true, timeout_interval: config[:refill][:timeout]) { refill }
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@refill_task.execute
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end
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end
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