Class: PostHog::FeatureFlagsPoller

Inherits:
Object
  • Object
show all
Includes:
Logging, Utils
Defined in:
lib/posthog/feature_flags.rb

Constant Summary

Constants included from Utils

Utils::UTC_OFFSET_WITHOUT_COLON, Utils::UTC_OFFSET_WITH_COLON

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Utils

convert_to_datetime, date_in_iso8601, datetime_in_iso8601, formatted_offset, is_valid_regex, isoify_dates, isoify_dates!, seconds_to_utc_offset, stringify_keys, symbolize_keys, symbolize_keys!, time_in_iso8601, uid

Methods included from Logging

included, #logger

Constructor Details

#initialize(polling_interval, personal_api_key, project_api_key, host, feature_flag_request_timeout_seconds, on_error = nil) ⇒ FeatureFlagsPoller

Returns a new instance of FeatureFlagsPoller.



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# File 'lib/posthog/feature_flags.rb', line 17

def initialize(
  polling_interval,
  personal_api_key,
  project_api_key,
  host,
  feature_flag_request_timeout_seconds,
  on_error = nil
)
  @polling_interval = polling_interval || 30
  @personal_api_key = personal_api_key
  @project_api_key = project_api_key
  @host = host
  @feature_flags = Concurrent::Array.new
  @group_type_mapping = Concurrent::Hash.new
  @loaded_flags_successfully_once = Concurrent::AtomicBoolean.new
  @feature_flags_by_key = nil
  @feature_flag_request_timeout_seconds = feature_flag_request_timeout_seconds
  @on_error = on_error || proc { |status, error| }
  @quota_limited = Concurrent::AtomicBoolean.new(false)
  @task =
    Concurrent::TimerTask.new(
      execution_interval: polling_interval
    ) { _load_feature_flags }

  # If no personal API key, disable local evaluation & thus polling for definitions
  if @personal_api_key.nil?
    logger.info 'No personal API key provided, disabling local evaluation'
    @loaded_flags_successfully_once.make_true
  else
    # load once before timer
    load_feature_flags
    @task.execute
  end
end

Class Method Details

.compare(lhs, rhs, operator) ⇒ Object

Class methods



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# File 'lib/posthog/feature_flags.rb', line 323

def self.compare(lhs, rhs, operator)
  case operator
  when 'gt'
    lhs > rhs
  when 'gte'
    lhs >= rhs
  when 'lt'
    lhs < rhs
  when 'lte'
    lhs <= rhs
  else
    raise "Invalid operator: #{operator}"
  end
end

.match_property(property, property_values) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 369

def self.match_property(property, property_values)
  # only looks for matches where key exists in property_values
  # doesn't support operator is_not_set

  PostHog::Utils.symbolize_keys! property
  PostHog::Utils.symbolize_keys! property_values

  key = property[:key].to_sym
  value = property[:value]
  operator = property[:operator] || 'exact'

  if !property_values.key?(key)
    raise InconclusiveMatchError, "Property #{key} not found in property_values"
  elsif operator == 'is_not_set'
    raise InconclusiveMatchError, 'Operator is_not_set not supported'
  end

  override_value = property_values[key]

  case operator
  when 'exact', 'is_not'
    if value.is_a?(Array)
      values_stringified = value.map { |val| val.to_s.downcase }
      return values_stringified.any?(override_value.to_s.downcase) if operator == 'exact'

      return values_stringified.none?(override_value.to_s.downcase)

    end
    if operator == 'exact'
      value.to_s.downcase == override_value.to_s.downcase
    else
      value.to_s.downcase != override_value.to_s.downcase
    end
  when 'is_set'
    property_values.key?(key)
  when 'icontains'
    override_value.to_s.downcase.include?(value.to_s.downcase)
  when 'not_icontains'
    !override_value.to_s.downcase.include?(value.to_s.downcase)
  when 'regex'
    PostHog::Utils.is_valid_regex(value.to_s) && !Regexp.new(value.to_s).match(override_value.to_s).nil?
  when 'not_regex'
    PostHog::Utils.is_valid_regex(value.to_s) && Regexp.new(value.to_s).match(override_value.to_s).nil?
  when 'gt', 'gte', 'lt', 'lte'
    parsed_value = nil
    begin
      parsed_value = Float(value)
    rescue StandardError # rubocop:disable Lint/SuppressedException
    end
    if !parsed_value.nil? && !override_value.nil?
      if override_value.is_a?(String)
        compare(override_value, value.to_s, operator)
      else
        compare(override_value, parsed_value, operator)
      end
    else
      compare(override_value.to_s, value.to_s, operator)
    end
  when 'is_date_before', 'is_date_after'
    override_date = PostHog::Utils.convert_to_datetime(override_value.to_s)
    parsed_date = relative_date_parse_for_feature_flag_matching(value.to_s)

    parsed_date = PostHog::Utils.convert_to_datetime(value.to_s) if parsed_date.nil?

    raise InconclusiveMatchError, 'Invalid date format' unless parsed_date

    if operator == 'is_date_before'
      override_date < parsed_date
    elsif operator == 'is_date_after'
      override_date > parsed_date
    end
  else
    raise InconclusiveMatchError, "Unknown operator: #{operator}"
  end
end

.relative_date_parse_for_feature_flag_matching(value) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 338

def self.relative_date_parse_for_feature_flag_matching(value)
  match = /^-?([0-9]+)([a-z])$/.match(value)
  parsed_dt = DateTime.now.new_offset(0)
  return unless match

  number = match[1].to_i

  if number >= 10_000
    # Guard against overflow, disallow numbers greater than 10_000
    return nil
  end

  interval = match[2]
  case interval
  when 'h'
    parsed_dt -= (number / 24.0)
  when 'd'
    parsed_dt = parsed_dt.prev_day(number)
  when 'w'
    parsed_dt = parsed_dt.prev_day(number * 7)
  when 'm'
    parsed_dt = parsed_dt.prev_month(number)
  when 'y'
    parsed_dt = parsed_dt.prev_year(number)
  else
    return nil
  end

  parsed_dt
end

Instance Method Details

#get_all_flags(distinct_id, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 205

def get_all_flags(
  distinct_id,
  groups = {},
  person_properties = {},
  group_properties = {},
  only_evaluate_locally = false
)
  if @quota_limited.true?
    logger.debug 'Not fetching flags from server - quota limited'
    return {}
  end

  # returns a string hash of all flags
  response = get_all_flags_and_payloads(
    distinct_id,
    groups,
    person_properties,
    group_properties,
    only_evaluate_locally
  )

  response[:featureFlags]
end

#get_all_flags_and_payloads(distinct_id, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = false, raise_on_error = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 229

def get_all_flags_and_payloads(
  distinct_id,
  groups = {},
  person_properties = {},
  group_properties = {},
  only_evaluate_locally = false,
  raise_on_error = false
)
  load_feature_flags

  flags = {}
  payloads = {}
  fallback_to_server = @feature_flags.empty?
  request_id = nil # Only for /flags requests

  @feature_flags.each do |flag|
    begin
      match_value = _compute_flag_locally(flag, distinct_id, groups, person_properties, group_properties)
      flags[flag[:key]] = match_value
      match_payload = _compute_flag_payload_locally(flag[:key], match_value)
      payloads[flag[:key]] = match_payload if match_payload
    rescue InconclusiveMatchError
      fallback_to_server = true
    rescue StandardError => e
      @on_error.call(-1, "Error computing flag locally: #{e}. #{e.backtrace.join("\n")} ")
      fallback_to_server = true
    end
  end

  if fallback_to_server && !only_evaluate_locally
    begin
      flags_and_payloads = get_flags(distinct_id, groups, person_properties, group_properties)

      unless flags_and_payloads.key?(:featureFlags)
        raise StandardError, "Error flags response: #{flags_and_payloads}"
      end

      # Check if feature_flags are quota limited
      if flags_and_payloads[:quotaLimited] && flags_and_payloads[:quotaLimited].include?('feature_flags')
        logger.warn '[FEATURE FLAGS] Quota limited for feature flags'
        flags = {}
        payloads = {}
      else
        flags = stringify_keys(flags_and_payloads[:featureFlags] || {})
        payloads = stringify_keys(flags_and_payloads[:featureFlagPayloads] || {})
        request_id = flags_and_payloads[:requestId]
      end
    rescue StandardError => e
      @on_error.call(-1, "Error computing flag remotely: #{e}")
      raise if raise_on_error
    end
  end

  {
    featureFlags: flags,
    featureFlagPayloads: payloads,
    requestId: request_id
  }
end

#get_feature_flag(key, distinct_id, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 139

def get_feature_flag(
  key,
  distinct_id,
  groups = {},
  person_properties = {},
  group_properties = {},
  only_evaluate_locally = false
)
  # make sure they're loaded on first run
  load_feature_flags

  symbolize_keys! groups
  symbolize_keys! person_properties
  symbolize_keys! group_properties

  group_properties.each_value do |value|
    symbolize_keys!(value)
  end

  response = nil
  feature_flag = nil

  @feature_flags.each do |flag|
    if key == flag[:key]
      feature_flag = flag
      break
    end
  end

  unless feature_flag.nil?
    begin
      response = _compute_flag_locally(feature_flag, distinct_id, groups, person_properties, group_properties)
      logger.debug "Successfully computed flag locally: #{key} -> #{response}"
    rescue InconclusiveMatchError => e
      logger.debug "Failed to compute flag #{key} locally: #{e}"
    rescue StandardError => e
      @on_error.call(-1, "Error computing flag locally: #{e}. #{e.backtrace.join("\n")}")
    end
  end

  flag_was_locally_evaluated = !response.nil?

  request_id = nil

  if !flag_was_locally_evaluated && !only_evaluate_locally
    begin
      flags_data = get_all_flags_and_payloads(distinct_id, groups, person_properties, group_properties, false, true)
      if flags_data.key?(:featureFlags)
        flags = stringify_keys(flags_data[:featureFlags] || {})
        request_id = flags_data[:requestId]
      else
        logger.debug "Missing feature flags key: #{flags_data.to_json}"
        flags = {}
      end

      response = flags[key]
      response = false if response.nil?
      logger.debug "Successfully computed flag remotely: #{key} -> #{response}"
    rescue StandardError => e
      @on_error.call(-1, "Error computing flag remotely: #{e}. #{e.backtrace.join("\n")}")
    end
  end

  [response, flag_was_locally_evaluated, request_id]
end

#get_feature_flag_payload(key, distinct_id, match_value = nil, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 289

def get_feature_flag_payload(
  key,
  distinct_id,
  match_value = nil,
  groups = {},
  person_properties = {},
  group_properties = {},
  only_evaluate_locally = false
)
  if match_value.nil?
    match_value = get_feature_flag(
      key,
      distinct_id,
      groups,
      person_properties,
      group_properties,
      true
    )[0]
  end
  response = nil
  response = _compute_flag_payload_locally(key, match_value) unless match_value.nil?
  if response.nil? && !only_evaluate_locally
    flags_payloads = get_feature_payloads(distinct_id, groups, person_properties, group_properties)
    response = flags_payloads[key.downcase] || nil
  end
  response
end

#get_feature_payloads(distinct_id, groups = {}, person_properties = {}, group_properties = {}, _only_evaluate_locally = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 83

def get_feature_payloads(
  distinct_id,
  groups = {},
  person_properties = {},
  group_properties = {},
  _only_evaluate_locally = false
)
  flags_data = get_all_flags_and_payloads(
    distinct_id,
    groups,
    person_properties,
    group_properties
  )

  if flags_data.key?(:featureFlagPayloads)
    stringify_keys(flags_data[:featureFlagPayloads] || {})
  else
    logger.debug "Missing feature flag payloads key: #{flags_data.to_json}"
    {}
  end
end

#get_feature_variants(distinct_id, groups = {}, person_properties = {}, group_properties = {}, raise_on_error = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 58

def get_feature_variants(
  distinct_id,
  groups = {},
  person_properties = {},
  group_properties = {},
  raise_on_error = false
)
  # TODO: Convert to options hash for easier argument passing
  flags_data = get_all_flags_and_payloads(
    distinct_id,
    groups,
    person_properties,
    group_properties,
    false,
    raise_on_error
  )

  if flags_data.key?(:featureFlags)
    stringify_keys(flags_data[:featureFlags] || {})
  else
    logger.debug "Missing feature flags key: #{flags_data.to_json}"
    {}
  end
end

#get_flags(distinct_id, groups = {}, person_properties = {}, group_properties = {}) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 105

def get_flags(distinct_id, groups = {}, person_properties = {}, group_properties = {})
  request_data = {
    distinct_id: distinct_id,
    groups: groups,
    person_properties: person_properties,
    group_properties: group_properties
  }

  flags_response = _request_feature_flag_evaluation(request_data)

  # Only normalize if we have flags in the response
  if flags_response[:flags]
    # v4 format
    flags_hash = flags_response[:flags].transform_values do |flag|
      FeatureFlag.new(flag)
    end
    flags_response[:flags] = flags_hash
    flags_response[:featureFlags] = flags_hash.transform_values(&:get_value).transform_keys(&:to_sym)
    flags_response[:featureFlagPayloads] = flags_hash.transform_values(&:payload).transform_keys(&:to_sym)
  elsif flags_response[:featureFlags]
    # v3 format
    flags_response[:featureFlags] = flags_response[:featureFlags] || {}
    flags_response[:featureFlagPayloads] = flags_response[:featureFlagPayloads] || {}
    flags_response[:flags] = flags_response[:featureFlags].map do |key, value|
      [key, FeatureFlag.from_value_and_payload(key, value, flags_response[:featureFlagPayloads][key])]
    end.to_h
  end
  flags_response
end

#get_remote_config_payload(flag_key) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 135

def get_remote_config_payload(flag_key)
  _request_remote_config_payload(flag_key)
end

#load_feature_flags(force_reload = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 52

def load_feature_flags(force_reload = false)
  return unless @loaded_flags_successfully_once.false? || force_reload

  _load_feature_flags
end

#shutdown_poller ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 317

def shutdown_poller
  @task.shutdown
end