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) ⇒ FeatureFlagsPoller

Returns a new instance of FeatureFlagsPoller.



17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
 
# File 'lib/posthog/feature_flags.rb', line 17

def initialize(polling_interval, personal_api_key, project_api_key, host)
  @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

  @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



208
209
210
211
212
213
214
215
216
217
218
219
220
 
# File 'lib/posthog/feature_flags.rb', line 208

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 



254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
 
# File 'lib/posthog/feature_flags.rb', line 254

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 



222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
 
# File 'lib/posthog/feature_flags.rb', line 222

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



58
59
60
61
62
63
64
65
66
67
 
# File 'lib/posthog/feature_flags.rb', line 58

def _get_active_feature_variants(distinct_id, groups={}, person_properties={}, group_properties={})
  feature_variants = get_feature_variants(distinct_id, groups, person_properties, group_properties)
  active_feature_variants = {}
  feature_variants.each do |key, value|
    if value != false
      active_feature_variants[key] = value
    end
  end
  active_feature_variants
end

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



140
141
142
143
144
 
# File 'lib/posthog/feature_flags.rb', line 140

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) ⇒ Object 



146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
 
# File 'lib/posthog/feature_flags.rb', line 146

def get_all_flags_and_payloads(distinct_id, groups = {}, person_properties = {}, group_properties = {}, only_evaluate_locally = 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
      logger.error "Error computing flag locally: #{e}."
      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)
      flags = stringify_keys(flags_and_payloads[:featureFlags] || {})
      payloads = stringify_keys(flags_and_payloads[:featureFlagPayloads] || {})
    rescue StandardError => e
      logger.error "Error computing flag remotely: #{e}"
    end
  end
  {"featureFlags": flags, "featureFlagPayloads": payloads}
end

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



78
79
80
81
82
83
84
85
86
87
 
# File 'lib/posthog/feature_flags.rb', line 78

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 



89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
 
# File 'lib/posthog/feature_flags.rb', line 89

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
      logger.error "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)
      response = flags[key]
      if response.nil?
        response = false
      end
      logger.debug "Successfully computed flag remotely: #{key} -> #{response}"
    rescue StandardError => e
      logger.error "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 



180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
 
# File 'lib/posthog/feature_flags.rb', line 180

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 



69
70
71
72
73
74
75
76
 
# File 'lib/posthog/feature_flags.rb', line 69

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

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



49
50
51
52
53
54
55
56
 
# File 'lib/posthog/feature_flags.rb', line 49

def get_feature_variants(distinct_id, groups={}, person_properties={}, group_properties={})
  decide_data = get_decide(distinct_id, groups, person_properties, group_properties)
  if !decide_data.key?(:featureFlags)
    logger.error "Missing feature flags key: #{decide_data.to_json}"
  else
    stringify_keys(decide_data[:featureFlags] || {})
  end
end

#load_feature_flags(force_reload = false) ⇒ Object 



43
44
45
46
47
 
# File 'lib/posthog/feature_flags.rb', line 43

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

#shutdown_poller ⇒ Object 



202
203
204
 
# File 'lib/posthog/feature_flags.rb', line 202

def shutdown_poller()
  @task.shutdown
end