Class: WavefrontCli::Base

Inherits:
Object
  • Object
show all
Includes:
Wavefront::Validators, Constants
Defined in:
lib/wavefront-cli/base.rb

Overview

Parent of all the CLI classes. This class uses metaprogramming techniques to try to make adding new CLI commands and sub-commands as simple as possible.

To define a subcommand ‘cmd’, you only need add it to the ‘docopt` description in the relevant section, and create a method ’do_cmd’. The WavefrontCli::Base::dispatch() method will find it, and call it. If your subcommand has multiple words, like ‘delete tag’, your do method would be called ‘do_delete_tag`. The `do_` methods are able to access the Wavefront SDK object as `wf`, and all docopt options as `options`.

Constant Summary

Constants included from Constants

Constants::ALL_PAGE_SIZE, Constants::DEFAULT_CONFIG, Constants::DEFAULT_OPTS, Constants::HUMAN_TIME_FORMAT, Constants::HUMAN_TIME_FORMAT_MS

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Base

Returns a new instance of Base.



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# File 'lib/wavefront-cli/base.rb', line 28

def initialize(options)
  @options = options
  sdk_class = _sdk_class
  @klass_word = sdk_class.split('::').last.downcase
  validate_input

  options_and_exit if options[:help]

  require File.join('wavefront-sdk', @klass_word)
  @klass = Object.const_get(sdk_class)

  send(:post_initialize, options) if respond_to?(:post_initialize)
end

Instance Attribute Details

#klass ⇒ Object

Returns the value of attribute klass.



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# File 'lib/wavefront-cli/base.rb', line 23

def klass
  @klass
end

#klass_word ⇒ Object

Returns the value of attribute klass_word.



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# File 'lib/wavefront-cli/base.rb', line 23

def klass_word
  @klass_word
end

#options ⇒ Object

Returns the value of attribute options.



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# File 'lib/wavefront-cli/base.rb', line 23

def options
  @options
end

#wf ⇒ Object

Returns the value of attribute wf.



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# File 'lib/wavefront-cli/base.rb', line 23

def wf
  @wf
end

Instance Method Details

#_sdk_class ⇒ Object

Normally we map the class name to a similar one in the SDK. Overriding his method lets you map to something else.



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# File 'lib/wavefront-cli/base.rb', line 45

def _sdk_class
  self.class.name.sub(/Cli/, '')
end

#cannot_noop! ⇒ Object

Operations which do require multiple operations cannot be perormed as a no-op. Drop in a call to this method for those things. The exception is caught in controller.rb

Raises:



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# File 'lib/wavefront-cli/base.rb', line 492

def cannot_noop!
  raise WavefrontCli::Exception::UnsupportedNoop if options[:noop]
end

#check_status(status) ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 249

def check_status(status)
  status.respond_to?(:result) && status.result == 'OK'
end

#conds_to_query(conds) ⇒ Object

Turn a list of search conditions into an API query



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# File 'lib/wavefront-cli/base.rb', line 453

def conds_to_query(conds)
  conds.each_with_object([]) do |cond, aggr|
    key, value = cond.split(/\W/, 2)
    q = { key: key, value: value }
    q[:matchingMethod] = 'EXACT' if cond.start_with?("#{key}=")
    q[:matchingMethod] = 'STARTSWITH' if cond.start_with?("#{key}^")
    aggr.<< q
  end
end

#dispatch ⇒ nil

Works out the user’s command by matching any options docopt has set to ‘true’ with any ‘do_’ method in the class. Then calls that method, and displays whatever it returns.

rubocop:disable Metrics/AbcSize

Returns:

Raises:

  • WavefrontCli::Exception::UnhandledCommand if the command does not match a ‘do_` method.



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# File 'lib/wavefront-cli/base.rb', line 168

def dispatch
  #
  # Take a list of do_ methods, remove the 'do_' from their name,
  # and break them into arrays of '_' separated words.
  #
  m_list = methods.select { |m| m.to_s.start_with?('do_') }.map do |m|
    m.to_s.split('_')[1..-1]
  end

  # Sort that array of arrays by length, longest first.  Then look
  # through each deconstructed method name and see if the user
  # supplied an option for each component. Call the first one that
  # matches. The order will ensure we match "do_delete_tags" before
  # we match "do_delete".
  #
  m_list.sort_by(&:length).reverse_each do |m|
    if m.reject { |w| options[w.to_sym] }.empty?
      method = (%w[do] + m).join('_')
      return display(public_send(method), method)
    end
  end

  if respond_to?(:do_default)
    return display(public_send(:do_default), :do_default)
  end

  raise WavefrontCli::Exception::UnhandledCommand
end

#display(data, method) ⇒ Object

Display a Ruby object as JSON, YAML, or human-readable. We provide a default method to format human-readable output, but you can override it by creating your own ‘humanize_command_output` method control how its output is handled by setting the `response` instance variable.

rubocop:disable Metrics/AbcSize

Parameters:

  • an object returned by a Wavefront SDK method. This will contain ‘response’ and ‘status’ structures.

  • the name of the method which produced this output. Used to find a suitable humanize method.



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# File 'lib/wavefront-cli/base.rb', line 212

def display(data, method)
  if no_api_response.include?(method)
    return display_no_api_response(data, method)
  end

  exit if options[:noop]

  i[status response].each do |b|
    abort "no #{b} block in API response" unless data.respond_to?(b)
  end

  unless check_status(data.status)
    handle_error(method, data.status.code) if format_var == :human
    display_api_error(data.status)
  end

  handle_response(data.response, format_var, method)
end

#display_api_error(status) ⇒ Object

Returns System exit.

Parameters:

  • status object from SDK response

Returns:

  • System exit



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# File 'lib/wavefront-cli/base.rb', line 235

def display_api_error(status)
  if  status.code == 404
    abort 'API path not found. Perhaps your account does not ' \
          'support this feature.'
  end

  msg = status.message || 'No further information'
  abort format('ERROR: API code %s: %s.', status.code, msg.chomp('.'))
end

#display_no_api_response(data, method) ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 245

def display_no_api_response(data, method)
  handle_response(data, format_var, method)
end

#do_delete ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 393

def do_delete
  wf.delete(options[:'<id>'])
end

#do_describe ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 376

def do_describe
  wf.describe(options[:'<id>'])
end

#do_import ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 380

def do_import
  raw = load_file(options[:'<file>'])

  begin
    prepped = import_to_create(raw)
  rescue StandardError => e
    puts e if options[:debug]
    raise WavefrontCli::Exception::UnparseableInput
  end

  wf.create(prepped)
end

#do_list ⇒ Object

Below here are common methods. Most are used by most classes, but if they don’t match a command described in the docopt text, the dispatcher will never call them. So, there’s no harm inheriting unneeded things. Some classes override them.



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# File 'lib/wavefront-cli/base.rb', line 366

def do_list
  list = if options[:all]
           wf.list(ALL_PAGE_SIZE, :all)
         else
           wf.list(options[:offset] || 0, options[:limit] || 100)
         end

  respond_to?(:list_filter) ? list_filter(list) : list
end

#do_search(cond = ) ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 422

def do_search(cond = options[:'<condition>'])
  require 'wavefront-sdk/search'
  wfs = Wavefront::Search.new(mk_creds, mk_opts)
  query = conds_to_query(cond)
  wfs.search(search_key, query, range_hash)
end

#do_undelete ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 412

def do_undelete
  wf.undelete(options[:'<id>'])
end

#do_update ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 416

def do_update
  cannot_noop!
  k, v = options[:'<key=value>'].split('=', 2)
  wf.update(options[:'<id>'], k => v)
end

#extract_values(obj, key, aggr = []) ⇒ Array

A recursive function which fetches list of values from a nested hash. Used by WavefrontCli::Dashboard#do_queries

Parameters:

  • the thing to search

  • the key to search for

  • (defaults to: [])

    values of matched keys

Returns:



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# File 'lib/wavefront-cli/base.rb', line 503

def extract_values(obj, key, aggr = [])
  if obj.is_a?(Hash)
    obj.each_pair do |k, v|
      if k == key && !v.to_s.empty?
        aggr.<< v
      else
        extract_values(v, key, aggr)
      end
    end
  elsif obj.is_a?(Array)
    obj.each { |e| extract_values(e, key, aggr) }
  end

  aggr
end

#failed_validation_message(input) ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 114

def failed_validation_message(input)
  format("'%s' is not a valid %s ID.", input, klass_word)
end

#format_var ⇒ Symbol

To allow a user to default to different output formats for different object, we are able to define a format for each class. instance, ‘alertformat` or `agentformat`. This method returns such a string appropriate for the inheriting class.

Returns:

  • name of the option or config-file key which sets the default output format for this class



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# File 'lib/wavefront-cli/base.rb', line 153

def format_var
  options[:format].to_sym
rescue NoMethodError
  :human
end

#handle_error(method, code) ⇒ Object

This gives us a chance to catch different errors in WavefrontDisplay classes. If nothing catches, them abort.



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# File 'lib/wavefront-cli/base.rb', line 256

def handle_error(method, code)
  k = load_display_class
  k.new({}, options).run_error([method, code].join('_'))
end

#handle_response(resp, format, method) ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 261

def handle_response(resp, format, method)
  if format == :human
    k = load_display_class
    k.new(resp, options).run(method)
  else
    parseable_output(format, resp)
  end
end

#hcl_fields ⇒ Object

rubocop:enable Metrics/AbcSize



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# File 'lib/wavefront-cli/base.rb', line 285

def hcl_fields
  []
end

#import_to_create(raw) ⇒ Object

Most things will re-import with the POST method if you remove the ID.



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# File 'lib/wavefront-cli/base.rb', line 466

def import_to_create(raw)
  raw.each_with_object({}) do |(k, v), a|
    a[k.to_sym] = v unless k == 'id'
  end
end

#load_display_class ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 289

def load_display_class
  require_relative File.join('display', klass_word)
  Object.const_get(klass.name.sub('Wavefront', 'WavefrontDisplay'))
end

#load_file(path) ⇒ Hash

Give it a path to a file (as a string) and it will return the contents of that file as a Ruby object. Automatically detects JSON and YAML. Raises an exception if it doesn’t look like either. If path is ‘-’ then it will read STDIN.

rubocop:disable Metrics/AbcSize

Parameters:

  • the file to load

Returns:

  • a Ruby object of the loaded file

Raises:

  • WavefrontCli::Exception::UnsupportedFileFormat if the filetype is unknown.

  • pass through any error loading or parsing the file



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# File 'lib/wavefront-cli/base.rb', line 323

def load_file(path)
  return load_from_stdin if path == '-'

  file = Pathname.new(path)

  raise WavefrontCli::Exception::FileNotFound unless file.exist?

  if file.extname == '.json'
    JSON.parse(IO.read(file))
  elsif file.extname == '.yaml' || file.extname == '.yml'
    YAML.safe_load(IO.read(file))
  else
    raise WavefrontCli::Exception::UnsupportedFileFormat
  end
end

#load_from_stdin ⇒ Object

Read STDIN and return a Ruby object, assuming that STDIN is valid JSON or YAML. This is a dumb method, it does no buffering, so STDIN must be a single block of data. This appears to be a valid assumption for use-cases of this CLI.

Returns:

Raises:

  • Wavefront::Exception::UnparseableInput if the input does not parse



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# File 'lib/wavefront-cli/base.rb', line 349

def load_from_stdin
  raw = STDIN.read

  if raw.start_with?('---')
    YAML.safe_load(raw)
  else
    JSON.parse(raw)
  end
rescue RuntimeError
  raise Wavefront::Exception::UnparseableInput
end

#mk_creds ⇒ Hash

Make a wavefront-sdk credentials object from standard options.

Returns:

  • containing ‘token` and `endpoint`.



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# File 'lib/wavefront-cli/base.rb', line 123

def mk_creds
  { token:    options[:token],
    endpoint: options[:endpoint],
    agent:    "wavefront-cli-#{WF_CLI_VERSION}" }
end

#mk_opts ⇒ Hash

Make a common wavefront-sdk options object from standard CLI options. We force verbosity on for a noop, otherwise we get no output.

Returns:

  • containing ‘debug`, `verbose`, and `noop`.



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# File 'lib/wavefront-cli/base.rb', line 135

def mk_opts
  ret = { debug:   options[:debug],
          noop:    options[:noop] }

  ret[:verbose] = options[:noop] ? true : options[:verbose]

  ret.merge!(extra_options) if respond_to?(:extra_options)
  ret
end

#no_api_response ⇒ Array[String]

Some subcommands don’t make an API call, so they don’t return a Wavefront::Response object. You can override this method with something which returns an array of methods like that. They will bypass the usual response checking.

response

Returns:

  • methods which do not include an API



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# File 'lib/wavefront-cli/base.rb', line 57

def no_api_response
  []
end

#ok_exit(message) ⇒ Object

Print a message and exit 0



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# File 'lib/wavefront-cli/base.rb', line 67

def ok_exit(message)
  puts message
  exit 0
end

#one_or_all ⇒ Object

Return a detailed description of one item, if an ID has been given, or all items if it has not.



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# File 'lib/wavefront-cli/base.rb', line 475

def one_or_all
  if options[:'<id>']
    resp = wf.describe(options[:'<id>'])
    data = [resp.response]
  else
    options[:all] = true
    resp = do_list
    data = resp.response.items
  end

  [resp, data]
end

#options_and_exit ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 61

def options_and_exit
  ok_exit(options)
end

#parseable_output(format, resp) ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/wavefront-cli/base.rb', line 271

def parseable_output(format, resp)
  options[:class] = klass_word
  options[:hcl_fields] = hcl_fields
  require_relative File.join('output', format.to_s)
  oclass = Object.const_get(format('WavefrontOutput::%s',
                                   format.to_s.capitalize))
  oclass.new(resp, options).run
rescue LoadError
  raise(WavefrontCli::Exception::UnsupportedOutput,
        format("The '%s' command does not support '%s' output.",
               options[:class], format))
end

#range_hash ⇒ Object

If the user has specified –all, override any limit and offset values



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# File 'lib/wavefront-cli/base.rb', line 432

def range_hash
  if options[:all]
    limit  = :all
    offset = ALL_PAGE_SIZE
  else
    limit  = options[:limit]
    offset = options[:offset] || options[:cursor]
  end

  { limit: limit, offset: offset }
end

#run ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 72

def run
  @wf = klass.new(mk_creds, mk_opts)
  dispatch
end

#search_key ⇒ Object

The search URI pattern doesn’t always match the command name, or class name. Override this method if this is the case.



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# File 'lib/wavefront-cli/base.rb', line 447

def search_key
  klass_word
end

#smart_delete(object_type = klass_word) ⇒ Object

Some objects support soft deleting. To handle that, call this method from do_delete



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# File 'lib/wavefront-cli/base.rb', line 400

def smart_delete(object_type = klass_word)
  cannot_noop!
  puts smart_delete_message(object_type)
  wf.delete(options[:'<id>'])
end

#smart_delete_message(object_type) ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 406

def smart_delete_message(object_type)
  desc = wf.describe(options[:'<id>'])
  word = desc.ok? ? 'Soft' : 'Permanently'
  format("%s deleting %s '%s'", word, object_type, options[:'<id>'])
end

#validate_id ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 108

def validate_id
  send(validator_method, options[:'<id>'])
rescue validator_exception
  abort failed_validation_message(options[:'<id>'])
end

#validate_input ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 91

def validate_input
  validate_id if options[:'<id>']
  validate_tags if options[:'<tag>']
  send(:extra_validation) if respond_to?(:extra_validation)
end

#validate_opts ⇒ Object

There are things we need to have. If we don’t have them, stop the user right now. Also, if we’re in debug mode, print out a hash of options, which can be very useful when doing actual debugging. Some classes may have to override this method. The writer, for instance, uses a proxy and has no token.

Raises:



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# File 'lib/wavefront-cli/base.rb', line 300

def validate_opts
  unless options[:token]
    raise(WavefrontCli::Exception::CredentialError,
          'Missing API token.')
  end

  return true if options[:endpoint]
  raise(WavefrontCli::Exception::CredentialError,
        'Missing API endpoint.')
end

#validate_tags(key = :'<tag>') ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 97

def validate_tags(key = :'<tag>')
  Array(options[key]).each do |t|
    begin
      send(:wf_tag?, t)
    rescue Wavefront::Exception::InvalidTag
      raise(WavefrontCli::Exception::InvalidInput,
            "'#{t}' is not a valid tag.")
    end
  end
end

#validator_exception ⇒ Object 



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# File 'lib/wavefront-cli/base.rb', line 85

def validator_exception
  Object.const_get(
    "Wavefront::Exception::Invalid#{klass_word.capitalize}Id"
  )
end

#validator_method ⇒ Object

We normally validate with a predictable method name. Alert IDs are validated with #wf_alert_id? etc. If you need to change that, override this method.



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# File 'lib/wavefront-cli/base.rb', line 81

def validator_method
  "wf_#{klass_word}_id?".to_sym
end