Class: Krane::Kubectl

Inherits:
Object
  • Object
show all
Defined in:
lib/krane/kubectl.rb

Defined Under Namespace

Classes: ResourceNotFoundError

Constant Summary collapse

ERROR_MATCHERS = 
{
  not_found: /NotFound/,
  client_timeout: /Client\.Timeout exceeded while awaiting headers/,
}
DEFAULT_TIMEOUT = 
15
MAX_RETRY_DELAY = 
16
SERVER_DRY_RUN_MIN_VERSION = 
"1.13"

Instance Method Summary collapse

Constructor Details

#initialize(task_config:, log_failure_by_default:, default_timeout: DEFAULT_TIMEOUT, output_is_sensitive_default: false) ⇒ Kubectl

Returns a new instance of Kubectl.



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# File 'lib/krane/kubectl.rb', line 18

def initialize(task_config:, log_failure_by_default:, default_timeout: DEFAULT_TIMEOUT,
  output_is_sensitive_default: false)
  @task_config = task_config
  @log_failure_by_default = log_failure_by_default
  @default_timeout = default_timeout
  @output_is_sensitive_default = output_is_sensitive_default
end

Instance Method Details

#client_version ⇒ Object 



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# File 'lib/krane/kubectl.rb', line 78

def client_version
  version_info[:client]
end

#retry_delay(attempt) ⇒ Object 



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# File 'lib/krane/kubectl.rb', line 64

def retry_delay(attempt)
  # exponential backoff starting at 1s with cap at 16s, offset by up to 0.5s
  [2**(attempt - 1), MAX_RETRY_DELAY].min - Random.rand(0.5).round(1)
end

#run(*args, log_failure: nil, use_context: true, use_namespace: true, output: nil, raise_if_not_found: false, attempts: 1, output_is_sensitive: nil, retry_whitelist: nil) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/krane/kubectl.rb', line 26

def run(*args, log_failure: nil, use_context: true, use_namespace: true, output: nil,
  raise_if_not_found: false, attempts: 1, output_is_sensitive: nil, retry_whitelist: nil)
  raise ArgumentError, "namespace is required" if namespace.blank? && use_namespace
  log_failure = @log_failure_by_default if log_failure.nil?
  output_is_sensitive = @output_is_sensitive_default if output_is_sensitive.nil?
  cmd = build_command_from_options(args, use_namespace, use_context, output)
  out, err, st = nil

  (1..attempts).to_a.each do |current_attempt|
    logger.debug("Running command (attempt #{current_attempt}): #{cmd.join(' ')}")
    out, err, st = Open3.capture3(*cmd)
    logger.debug("Kubectl out: " + out.gsub(/\s+/, ' ')) unless output_is_sensitive

    break if st.success?
    raise(ResourceNotFoundError, err) if err.match(ERROR_MATCHERS[:not_found]) && raise_if_not_found

    if log_failure
      warning = if current_attempt == attempts
        "The following command failed (attempt #{current_attempt}/#{attempts})"
      elsif retriable_err?(err, retry_whitelist)
        "The following command failed and will be retried (attempt #{current_attempt}/#{attempts})"
      else
        "The following command failed and cannot be retried"
      end
      logger.warn("#{warning}: #{Shellwords.join(cmd)}")
      logger.warn(err) unless output_is_sensitive
    else
      logger.debug("Kubectl err: #{output_is_sensitive ? '<suppressed sensitive output>' : err}")
    end
    StatsD.client.increment('kubectl.error', 1, tags: { context: context, namespace: namespace, cmd: cmd[1] })

    break unless retriable_err?(err, retry_whitelist) && current_attempt < attempts
    sleep(retry_delay(current_attempt))
  end

  [out.chomp, err.chomp, st]
end

#server_dry_run_enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/krane/kubectl.rb', line 86

def server_dry_run_enabled?
  server_version >= Gem::Version.new(SERVER_DRY_RUN_MIN_VERSION)
end

#server_version ⇒ Object 



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# File 'lib/krane/kubectl.rb', line 82

def server_version
  version_info[:server]
end

#version_info ⇒ Object 



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# File 'lib/krane/kubectl.rb', line 69

def version_info
  @version_info ||=
    begin
      response, _, status = run("version", use_namespace: false, log_failure: true)
      raise KubectlError, "Could not retrieve kubectl version info" unless status.success?
      extract_version_info_from_kubectl_response(response)
    end
end