Copy execution environment to Poseidon on create and update

When creating or updating an execution environment, an API call to
Poseidon is made with the necessary information to create the
corresponding Nomad job.

If runner management is configured, his will display a warning
(currently in the same color as if it were a success) in the UI, if the
API call fails. The environment is saved even if it fails.
If runner management is not configured, this warning will not be created.

app/models/execution_environment.rb

@@ -7,6 +7,10 @@ class ExecutionEnvironment < ApplicationRecord
   include DefaultValues
 
   VALIDATION_COMMAND = 'whoami'
+  RUNNER_MANAGEMENT_PRESENT = CodeOcean::Config.new(:code_ocean).read[:runner_management].present?
+  BASE_URL = CodeOcean::Config.new(:code_ocean).read[:runner_management][:url] if RUNNER_MANAGEMENT_PRESENT
+  HEADERS = {'Content-Type' => 'application/json'}.freeze
+  DEFAULT_CPU_LIMIT = 20
 
   after_initialize :set_default_values
 
@@ -26,6 +30,8 @@ class ExecutionEnvironment < ApplicationRecord
   validates :permitted_execution_time, numericality: {only_integer: true}, presence: true
   validates :pool_size, numericality: {only_integer: true}, presence: true
   validates :run_command, presence: true
+  validates :cpu_limit, presence: true, numericality: {greater_than: 0, only_integer: true}
+  validates :exposed_ports, format: {with: /\A(([[:digit:]]{1,5},)*([[:digit:]]{1,5}))?\z/}
 
   def set_default_values
     set_default_values_if_present(permitted_execution_time: 60, pool_size: 0)
@@ -36,6 +42,33 @@ class ExecutionEnvironment < ApplicationRecord
     name
   end
 
+  def copy_to_poseidon
+    return false unless RUNNER_MANAGEMENT_PRESENT
+
+    url = "#{BASE_URL}/execution-environments/#{id}"
+    response = Faraday.put(url, to_json, HEADERS)
+    return true if [201, 204].include? response.status
+
+    Rails.logger.warn("Could not create execution environment in Poseidon, got response: #{response.as_json}")
+    false
+  end
+
+  def to_json(*_args)
+    {
+      id: id,
+      image: docker_image,
+      prewarmingPoolSize: pool_size,
+      cpuLimit: cpu_limit,
+      memoryLimit: memory_limit,
+      networkAccess: network_enabled,
+      exposedPorts: exposed_ports_list,
+    }.to_json
+  end
+
+  def exposed_ports_list
+    (exposed_ports || '').split(',').map(&:to_i)
+  end
+
   def valid_test_setup?
     if test_command? ^ testing_framework?
       errors.add(:test_command,