Module: Util::KubectlOps

Extended by:
Logging
Defined in:
lib/util/kubectl_ops.rb

Constant Summary collapse

CONFIG_MAP_RESOURCE_NAME = 
'config_map'.freeze
RETRYABLE_STATUS_CODE =

Status codes for which retry is attempted (To represent 5xx, use 5)

[429, 5].freeze
MAX_ATTEMPTS = 
5
INITIAL_DELAY =

seconds

1
EXPONENT_CONSTANT =

‘e’ in exponential function (e^x) where x is number of retries

2

Constants included from Logging

Logging::SEV_LABEL, Logging::TRACE

Class Method Summary collapse

Methods included from Logging

logger, logger=

Class Method Details

.create_configmap(cm_name, namespace, data_hash) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 197

def create_configmap(cm_name, namespace, data_hash)
  # Create resource object for config map
  cm = Kubeclient::Resource.new
  cm.metadata = {}
  cm.metadata.name = cm_name
  cm.metadata.namespace = namespace
  cm.data = {}
  cm.data = data_hash

  object_type = CONFIG_MAP_RESOURCE_NAME
  client = Util::KubeClient.get_clients[:core_client]

  begin
    create_object(object_type, cm, client)
  rescue StandardError => e
    logger.error("Unable to create '#{object_type}/#{cm_name}'")
    raise e
  end
end

.create_object(object_type, kubeclient_resource_object, client) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 168

def create_object(object_type, kubeclient_resource_object, client)
  kube_apiserver_request(method: :create_object,
                         object_type: object_type,
                         client: client,
                         object: kubeclient_resource_object)
end

.get_configmap(cm_name, namespace) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 184

def get_configmap(cm_name, namespace)
  object_type = CONFIG_MAP_RESOURCE_NAME
  client = Util::KubeClient.get_clients[:core_client]
  begin
    response = get_object(object_type, cm_name, namespace, client)
  rescue StandardError => e
    return nil if e.error_code == 404

    raise e
  end
  response
end

.get_object(object_type, object_name, namespace, client, options = {}) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 159

def get_object(object_type, object_name, namespace, client, options = {})
  kube_apiserver_request(method: :get_object,
                         object_type: object_type,
                         client: client,
                         object_name: object_name,
                         namespace: namespace,
                         opts: options)
end

.get_objects(object_type, client = nil, options = {}) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 151

def get_objects(object_type, client = nil, options = {})
  options.merge!({ limit: @chunk_limit, continue: nil })
  kube_apiserver_request(method: :get_objects,
                         object_type: object_type,
                         client: client,
                         opts: options)
end

.kube_apiserver_request(method:, object_type:, client: nil, object_name: nil, namespace: nil, object: nil, patch: nil, opts: {}) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 44

def kube_apiserver_request(method:, object_type:, client: nil, object_name: nil, namespace: nil, object: nil, patch: nil, opts: {})
  response = nil
  retry_count = 0
  begin
    case method
    when :get_objects
      if client.nil?
        client = Util::KubeClient.get_clients[Enum::ObjectClientMapingEnum.const_get(object_type.upcase.to_s)]
      end
      logger.debug("Fetching '#{object_type}' details from all namespaces")
      method_verb = 'GET'
      opts.merge!({ as: :parsed_symbolized })
      response = {}
      loop do
        entities = client.public_send("get_#{object_type}", opts)
        continue = entities[:metadata][:continue]
        if response.empty?
          # when all objects are fetched via single API request
          if continue.nil?
            response = entities
            break
          end
          response = entities.clone
        else
          response[:items] += entities[:items]
        end
        break if continue.nil?

        logger.debug("remainingItemCount - #{entities[:metadata][:remainingItemCount]}")
        opts.merge!({ continue: continue })
      end
      if response.nil? || response.empty?
        logger.debug("Empty or null response recieved from Kubernetes API endpoint '#{client.rest_client.url}'.")
        return { parsed_symbolized: [], raw: '' }
      else
        return { parsed_symbolized: response, raw: JSON.dump(response) }
      end
    when :get_object
      method_verb = 'GET'
      logger.debug("Fetching '#{object_type}/#{object_name}' details")
      opts.merge!(as: :parsed_symbolized)
      response = client.public_send("get_#{object_type}", object_name, namespace, opts)
    when :create_object
      method_verb = 'CREATE'
      logger.debug("Creating '#{object_type}' - #{object}")
      response = client.public_send("create_#{object_type}", object)
    when :patch_object
      method_verb = 'PATCH'
      logger.debug("Patching '#{object_type}/#{object_name}' - #{patch}")
      response = client.public_send("patch_#{object_type}", object_name, patch, namespace)
    else
      raise SyntaxError, "Unsupported method - #{method} passed."
    end
  rescue KubeException => e
    if should_retry?(e, retry_count, object_type)
      retry_count += 1
      retry
    end

    if e.error_code.nil?
      logger.error("Unexpected error occurred while calling #{method_verb} '#{object_type}'. Error details: #{e}")
      raise e
    elsif e.error_code == 302
      logger.error("Max re-direct attempts while calling #{method_verb} '#{object_type}'. Error details: #{e}")
      raise StandardError, "Max re-direct attempts while calling #{method_verb} '#{object_type}'."
    elsif e.error_code == 401
      # In such cases, client should be re-created in order to refresh token
      logger.error("Not authorized to #{method_verb} '#{object_type}'. Error details: #{e}")
      raise StandardError, "Not authorized to #{method_verb} '#{object_type}'."
    elsif e.error_code == 403
      logger.error("Forbidden to #{method_verb} '#{object_type}'. Error details: #{e}")
      raise StandardError, "Forbidden to #{method_verb} '#{object_type}'."
    elsif e.error_code == 404
      logger.debug("Resource '#{object_type}' not found. Error details: #{e}")
      raise e
    elsif e.error_code == 410
      # ref - https://kubernetes.io/docs/reference/using-api/api-concepts/#retrieving-large-results-sets-in-chunks
      logger.error("Too many '#{object_type}' objects. Consider increasing CHUNK limit.")
      raise StandardError, "Too many '#{object_type}' objects. Consider increasing CHUNK limit."
    elsif e.error_code == 429
      logger.error("Encountered throttling while calling #{method_verb} '#{object_type}'. Error details: #{e}")
      raise StandardError, "Encountered throttling while #{method_verb} '#{object_type}'."
    elsif (e.error_code / 100) == 5
      logger.error("Unexpected error occurred while #{method_verb} '#{object_type}'. Error details: #{e}")
      raise StandardError, "Unexpected error occurred while #{method_verb} '#{object_type}'."
    else
      logger.error("Error '#{e}' encountered while #{method_verb} '#{object_type}' from Kubernetes API endpoint '#{client.rest_client.url}'")
      raise StandardError, "Error '#{e}' encountered while #{method_verb} '#{object_type}'."
    end
  rescue NoMethodError => e
    logger.error('Unexpected Error - Method not found.')
    raise e
  rescue StandardError => e
    logger.error("Error while #{method_verb} '#{object_type}'. Error: #{e}")

    if should_retry?(e, retry_count, object_type)
      retry_count += 1
      retry
    end

    error_msg = "Maximum retry attempts ('#{MAX_ATTEMPTS}') exceeded. Aborting fetch for '#{object_type}'."
    logger.error(error_msg)
    raise error error_msg
  end
  response
end

.patch_configmap(cm_name, namespace, data_hash) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 217

def patch_configmap(cm_name, namespace, data_hash)
  patch_hash = { data: data_hash }
  object_type = CONFIG_MAP_RESOURCE_NAME
  client = Util::KubeClient.get_clients[:core_client]
  begin
    patch_object(object_type, cm_name, patch_hash, namespace, client)
  rescue StandardError => e
    logger.error("Unable to patch '#{object_type}/#{cm_name}'")
    raise e
  end
end

.patch_object(object_type, object_name, patch_hash, namespace, client) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 175

def patch_object(object_type, object_name, patch_hash, namespace, client)
  kube_apiserver_request(method: :patch_object,
                         object_type: object_type,
                         client: client,
                         object_name: object_name,
                         patch: patch_hash,
                         namespace: namespace)
end

.set_chunk_limit(num) ⇒ Object 



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# File 'lib/util/kubectl_ops.rb', line 25

def set_chunk_limit(num)
  @chunk_limit = num
end

.should_retry?(error, retry_count, object_type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/util/kubectl_ops.rb', line 29

def should_retry?(error, retry_count, object_type)
  return false if error.error_code.nil? # for handling timeouts

  if (RETRYABLE_STATUS_CODE.include? error.error_code) || RETRYABLE_STATUS_CODE.include?(error.error_code / 100)
    if retry_count < MAX_ATTEMPTS
      # If e = 2, and initial delay is 10, intervals will be (1, 2, 4, 8, 16)
      sleep_interval = EXPONENT_CONSTANT.pow(retry_count) * INITIAL_DELAY
      logger.warn("Error while making API Server call - '#{object_type}'. Retrying in #{sleep_interval} seconds. HTTP status code: #{error.error_code}")
      sleep(sleep_interval)
      return true
    end
  end
  false
end