Editor: Allow file retrieval after code run

lib/runner/connection.rb

@@ -146,7 +146,7 @@ class Runner::Connection
         @strategy.destroy_at_management
         @error = Runner::Error::ExecutionTimeout.new('Execution exceeded its time limit')
       when :terminated_by_codeocean, :terminated_by_management
-        @exit_callback.call @exit_code
+        @exit_callback.call @exit_code, @strategy.retrieve_files
       when :terminated_by_client, :error
         @strategy.destroy_at_management
       else # :established

lib/runner/strategy.rb

@@ -33,6 +33,14 @@ class Runner::Strategy
     raise NotImplementedError
   end
 
+  def retrieve_files(_path:, _recursive:, privileged_execution:)
+    raise NotImplementedError
+  end
+
+  def download_file(_file, privileged_execution:, &_block)
+    raise NotImplementedError
+  end
+
   def attach_to_execution(_command, _event_loop, _starting_time, privileged_execution:)
     raise NotImplementedError
   end

lib/runner/strategy/docker_container_pool.rb

@@ -104,6 +104,10 @@ class Runner::Strategy::DockerContainerPool < Runner::Strategy
     Rails.logger.debug { "#{Time.zone.now.getutc.inspect}: Finished copying files" }
   end
 
+  def retrieve_files(_path:, _recursive:, privileged_execution:)
+    # The DockerContainerPool does not support retrieving files from the runner.
+  end
+
   def attach_to_execution(command, event_loop, starting_time, privileged_execution: false) # rubocop:disable Lint/UnusedMethodArgument for the keyword argument
     reset_inactivity_timer
 

lib/runner/strategy/null.rb

@@ -25,6 +25,12 @@ class Runner::Strategy::Null < Runner::Strategy
 
   def copy_files(_files); end
 
+  def retrieve_files(_path:, _recursive:, privileged_execution: false); end
+
+  def download_file(_file, privileged_execution: false, &_block) # rubocop:disable Lint/UnusedMethodArgument for the keyword argument
+    raise Runner::Error.new
+  end
+
   def attach_to_execution(command, event_loop, starting_time, privileged_execution: false) # rubocop:disable Lint/UnusedMethodArgument for the keyword argument
     socket = Connection.new(nil, self, event_loop)
     # We don't want to return an error if the execution environment is changed

lib/runner/strategy/poseidon.rb

@@ -132,6 +132,64 @@ class Runner::Strategy::Poseidon < Runner::Strategy
     Rails.logger.debug { "#{Time.zone.now.getutc.inspect}: Finished copying files" }
   end
 
+  def retrieve_files(path: './', recursive: true, privileged_execution: false)
+    url = "#{runner_url}/files"
+    params = {
+      path: path,
+      recursive: recursive,
+      privilegedExecution: privileged_execution || @execution_environment.privileged_execution,
+    }
+    Rails.logger.debug { "#{Time.zone.now.getutc.inspect}: Retrieving files at #{runner_url} with #{params}" }
+    response = self.class.http_connection.get url, params
+    case response.status
+      when 200
+        JSON.parse(response.body)
+      when 424
+        raise Runner::Error::WorkspaceError.new("The path #{path} is not available or could not be read.")
+      else
+        self.class.handle_error response
+    end
+  rescue Faraday::Error => e
+    raise Runner::Error::FaradayError.new("Request to Poseidon failed: #{e.inspect}")
+  ensure
+    Rails.logger.debug { "#{Time.zone.now.getutc.inspect}: Finished listing files" }
+  end
+
+  def download_file(file, privileged_execution: false, &block)
+    url = "#{runner_url}/files/raw"
+    params = {
+      path: file,
+      privilegedExecution: privileged_execution || @execution_environment.privileged_execution,
+    }
+    Rails.logger.debug { "#{Time.zone.now.getutc.inspect}: Download file #{params} from #{runner_url}" }
+    response = self.class.new_http_connection.get url, params do |request|
+      content_length = nil
+      content_type = nil
+      next if block.blank?
+
+      request.options.on_data = proc do |chunk, _overall_received_bytes, env|
+        next unless env.success?
+
+        content_length ||= env.response_headers['Content-Length'].presence&.to_i
+        content_type ||= env.response_headers['Content-Type'].presence || 'application/octet-stream'
+        yield chunk, content_length, content_type
+      end
+      request.options
+    end
+    case response.status
+      when 200
+        response.body
+      when 424
+        raise Runner::Error::WorkspaceError.new("The file #{file} is not available or could not be read.")
+      else
+        self.class.handle_error response
+    end
+  rescue Faraday::Error => e
+    raise Runner::Error::FaradayError.new("Request to Poseidon failed: #{e.inspect}")
+  ensure
+    Rails.logger.debug { "#{Time.zone.now.getutc.inspect}: Finished downloading file" }
+  end
+
   def attach_to_execution(command, event_loop, starting_time, privileged_execution: false)
     websocket_url = execute_command(command, privileged_execution: privileged_execution)
     socket = Connection.new(websocket_url, self, event_loop)
@@ -232,6 +290,12 @@ class Runner::Strategy::Poseidon < Runner::Strategy
     end
   end
 
+  def self.new_http_connection
+    Faraday.new(ssl: {ca_file: config[:ca_file]}, headers: headers) do |faraday|
+      faraday.adapter :net_http
+    end
+  end
+
   def self.parse(response)
     JSON.parse(response.body).deep_symbolize_keys
   rescue JSON::ParserError => e