1 files changed, 132 insertions, 0 deletions
diff --git a/app/services/pod_logs/base_service.rb b/app/services/pod_logs/base_service.rb
new file mode 100644
index 00000000000..668ee6b88a8
--- /dev/null
+++ b/app/services/pod_logs/base_service.rb
@@ -0,0 +1,132 @@
+# frozen_string_literal: true
+
+module PodLogs
+  class BaseService < ::BaseService
+    include ReactiveCaching
+    include Stepable
+
+    attr_reader :cluster, :namespace, :params
+
+    CACHE_KEY_GET_POD_LOG = 'get_pod_log'
+    K8S_NAME_MAX_LENGTH = 253
+
+    SUCCESS_RETURN_KEYS = %i(status logs pod_name container_name pods).freeze
+
+    def id
+      cluster.id
+    end
+
+    def initialize(cluster, namespace, params: {})
+      @cluster = cluster
+      @namespace = namespace
+      @params = filter_params(params.dup.stringify_keys).to_hash
+    end
+
+    def execute
+      with_reactive_cache(
+        CACHE_KEY_GET_POD_LOG,
+        namespace,
+        params
+      ) do |result|
+        result
+      end
+    end
+
+    def calculate_reactive_cache(request, _namespace, _params)
+      case request
+      when CACHE_KEY_GET_POD_LOG
+        execute_steps
+      else
+        exception = StandardError.new('Unknown reactive cache request')
+        Gitlab::ErrorTracking.track_and_raise_for_dev_exception(exception, request: request)
+        error(_('Unknown cache key'))
+      end
+    end
+
+    private
+
+    def valid_params
+      %w(pod_name container_name)
+    end
+
+    def check_arguments(result)
+      return error(_('Cluster does not exist')) if cluster.nil?
+      return error(_('Namespace is empty')) if namespace.blank?
+
+      success(result)
+    end
+
+    def check_param_lengths(_result)
+      pod_name = params['pod_name'].presence
+      container_name = params['container_name'].presence
+
+      if pod_name&.length.to_i > K8S_NAME_MAX_LENGTH
+        return error(_('pod_name cannot be larger than %{max_length}'\
+          ' chars' % { max_length: K8S_NAME_MAX_LENGTH }))
+      elsif container_name&.length.to_i > K8S_NAME_MAX_LENGTH
+        return error(_('container_name cannot be larger than'\
+          ' %{max_length} chars' % { max_length: K8S_NAME_MAX_LENGTH }))
+      end
+
+      success(pod_name: pod_name, container_name: container_name)
+    end
+
+    def get_raw_pods(result)
+      result[:raw_pods] = cluster.kubeclient.get_pods(namespace: namespace)
+
+      success(result)
+    end
+
+    def get_pod_names(result)
+      result[:pods] = result[:raw_pods].map(&:metadata).map(&:name)
+
+      success(result)
+    end
+
+    def check_pod_name(result)
+      # If pod_name is not received as parameter, get the pod logs of the first
+      # pod of this namespace.
+      result[:pod_name] ||= result[:pods].first
+
+      unless result[:pod_name]
+        return error(_('No pods available'))
+      end
+
+      unless result[:pods].include?(result[:pod_name])
+        return error(_('Pod does not exist'))
+      end
+
+      success(result)
+    end
+
+    def check_container_name(result)
+      pod_details = result[:raw_pods].first { |p| p.metadata.name == result[:pod_name] }
+      containers = pod_details.spec.containers.map(&:name)
+
+      # select first container if not specified
+      result[:container_name] ||= containers.first
+
+      unless result[:container_name]
+        return error(_('No containers available'))
+      end
+
+      unless containers.include?(result[:container_name])
+        return error(_('Container does not exist'))
+      end
+
+      success(result)
+    end
+
+    def pod_logs(result)
+      raise NotImplementedError
+    end
+
+    def filter_return_keys(result)
+      result.slice(*SUCCESS_RETURN_KEYS)
+    end
+
+    def filter_params(params)
+      params.slice(*valid_params)
+    end
+  end
+end