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| }

  @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 207

def self.compare(lhs, rhs, operator)
  if operator == "gt"
    return lhs > rhs
  elsif operator == "gte"
    return lhs >= rhs
  elsif operator == "lt"
    return lhs < rhs
  elsif operator == "lte"
    return 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 253

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.new("Property #{key} not found in property_values")
  elsif operator == 'is_not_set'
    raise InconclusiveMatchError.new("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 }
      if operator == 'exact'
        return values_stringified.any?(override_value.to_s.downcase)
      else
        return !values_stringified.any?(override_value.to_s.downcase)
      end
    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 => e
    end
    if !parsed_value.nil? && !override_value.nil?
      if override_value.is_a?(String)
        self.compare(override_value, value.to_s, operator)
      else
        self.compare(override_value, parsed_value, operator)
      end
    else
      self.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 = self.relative_date_parse_for_feature_flag_matching(value.to_s)

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

    if !parsed_date
      raise InconclusiveMatchError.new("Invalid date format")
    end
    if operator == 'is_date_before'
      return override_date < parsed_date
    elsif operator == 'is_date_after'
      return override_date > parsed_date
    end
  else
    raise InconclusiveMatchError.new("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 221

def self.relative_date_parse_for_feature_flag_matching(value)
  match = /^-?([0-9]+)([a-z])$/.match(value)
  parsed_dt = DateTime.now.new_offset(0)
  if match
    number = match[1].to_i

    if number >= 10000
      # Guard against overflow, disallow numbers greater than 10_000
      return nil
    end

    interval = match[2]
    if interval == "h"
      parsed_dt = parsed_dt - (number/24r)
    elsif interval == "d"
      parsed_dt = parsed_dt.prev_day(number)
    elsif interval == "w"
      parsed_dt = parsed_dt.prev_day(number*7)
    elsif interval == "m"
      parsed_dt = parsed_dt.prev_month(number)
    elsif interval == "y"
      parsed_dt = parsed_dt.prev_year(number)
    else
      return nil
    end
    parsed_dt
  else
    nil
  end
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 134

def get_all_flags(distinct_id, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = false)
  # returns a string hash of all flags
  response = get_all_flags_and_payloads(distinct_id, groups, person_properties, group_properties, only_evaluate_locally)
  flags = 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 140

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_decide = @feature_flags.empty?

  @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)
      if match_payload
        payloads[flag[:key]] = match_payload
      end
    rescue InconclusiveMatchError => e
      fallback_to_decide = true
    rescue StandardError => e
      @on_error.call(-1, "Error computing flag locally: #{e}. #{e.backtrace.join("\n")} ")
      fallback_to_decide = true
    end
  end
  if fallback_to_decide && !only_evaluate_locally
    begin
      flags_and_payloads = get_decide(distinct_id, groups, person_properties, group_properties)

      unless flags_and_payloads.key?(:featureFlags)
        raise StandardError.new("Error flags response: #{flags_and_payloads}")
      end
      flags = stringify_keys(flags_and_payloads[:featureFlags] || {})
      payloads = stringify_keys(flags_and_payloads[:featureFlagPayloads] || {})
    rescue StandardError => e
      @on_error.call(-1, "Error computing flag remotely: #{e}")
      raise if raise_on_error
    end
  end
  {"featureFlags": flags, "featureFlagPayloads": payloads}
end

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



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# File 'lib/posthog/feature_flags.rb', line 72

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

  decide_data = _request_feature_flag_evaluation(request_data)
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 83

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 do |key, 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

  if !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?

  if !flag_was_locally_evaluated && !only_evaluate_locally
    begin
      flags = get_feature_variants(distinct_id, groups, person_properties, group_properties, true)
      response = flags[key]
      if response.nil?
        response = false
      end
      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]
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 179

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
  if match_value != nil
    response = _compute_flag_payload_locally(key, match_value)
  end
  if response == nil and !only_evaluate_locally
    decide_payloads = get_feature_payloads(distinct_id, groups, person_properties, group_properties)
    response = decide_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 62

def get_feature_payloads(distinct_id, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = false)
  decide_data = get_all_flags_and_payloads(distinct_id, groups, person_properties, group_properties)
  if !decide_data.key?(:featureFlagPayloads)
    logger.debug "Missing feature flag payloads key: #{decide_data.to_json}"
    return {}
  else
    stringify_keys(decide_data[:featureFlagPayloads] || {})
  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 51

def get_feature_variants(distinct_id, groups={}, person_properties={}, group_properties={}, raise_on_error=false)
  # TODO: Convert to options hash for easier argument passing
  decide_data = get_all_flags_and_payloads(distinct_id, groups, person_properties, group_properties, false, raise_on_error)
  if !decide_data.key?(:featureFlags)
    logger.debug "Missing feature flags key: #{decide_data.to_json}"
    {}
  else
    stringify_keys(decide_data[:featureFlags] || {})
  end
end

#load_feature_flags(force_reload = false) ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 45

def load_feature_flags(force_reload = false)
  if @loaded_flags_successfully_once.false? || force_reload
    _load_feature_flags
  end
end

#shutdown_poller ⇒ Object 



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# File 'lib/posthog/feature_flags.rb', line 201

def shutdown_poller()
  @task.shutdown
end