1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
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
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
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
139
140
141
142
143
144
145
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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
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
252
253
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
|
require 'spec_helper'
describe Gitlab::Git::Storage::CircuitBreaker, clean_gitlab_redis_shared_state: true, broken_storage: true do
let(:storage_name) { 'default' }
let(:circuit_breaker) { described_class.new(storage_name, hostname) }
let(:hostname) { Gitlab::Environment.hostname }
let(:cache_key) { "storage_accessible:#{storage_name}:#{hostname}" }
before do
# Override test-settings for the circuitbreaker with something more realistic
# for these specs.
stub_storage_settings('default' => {
'path' => TestEnv.repos_path
},
'broken' => {
'path' => 'tmp/tests/non-existent-repositories'
},
'nopath' => { 'path' => nil }
)
end
def value_from_redis(name)
Gitlab::Git::Storage.redis.with do |redis|
redis.hmget(cache_key, name)
end.first
end
def set_in_redis(name, value)
Gitlab::Git::Storage.redis.with do |redis|
redis.hmset(cache_key, name, value)
end.first
end
describe '.reset_all!' do
it 'clears all entries form redis' do
set_in_redis(:failure_count, 10)
described_class.reset_all!
key_exists = Gitlab::Git::Storage.redis.with { |redis| redis.exists(cache_key) }
expect(key_exists).to be_falsey
end
it 'does not break when there are no keys in redis' do
expect { described_class.reset_all! }.not_to raise_error
end
end
describe '.for_storage' do
it 'only builds a single circuitbreaker per storage' do
expect(described_class).to receive(:new).once.and_call_original
breaker = described_class.for_storage('default')
expect(breaker).to be_a(described_class)
expect(described_class.for_storage('default')).to eq(breaker)
end
it 'returns a broken circuit breaker for an unknown storage' do
expect(described_class.for_storage('unknown').circuit_broken?).to be_truthy
end
it 'returns a broken circuit breaker when the path is not set' do
expect(described_class.for_storage('nopath').circuit_broken?).to be_truthy
end
end
describe '#initialize' do
it 'assigns the settings' do
expect(circuit_breaker.hostname).to eq(hostname)
expect(circuit_breaker.storage).to eq('default')
expect(circuit_breaker.storage_path).to eq(TestEnv.repos_path)
end
end
context 'circuitbreaker settings' do
before do
stub_application_setting(circuitbreaker_failure_count_threshold: 0,
circuitbreaker_failure_wait_time: 1,
circuitbreaker_failure_reset_time: 2,
circuitbreaker_storage_timeout: 3,
circuitbreaker_access_retries: 4,
circuitbreaker_backoff_threshold: 5)
end
describe '#failure_count_threshold' do
it 'reads the value from settings' do
expect(circuit_breaker.failure_count_threshold).to eq(0)
end
end
describe '#failure_wait_time' do
it 'reads the value from settings' do
expect(circuit_breaker.failure_wait_time).to eq(1)
end
end
describe '#failure_reset_time' do
it 'reads the value from settings' do
expect(circuit_breaker.failure_reset_time).to eq(2)
end
end
describe '#storage_timeout' do
it 'reads the value from settings' do
expect(circuit_breaker.storage_timeout).to eq(3)
end
end
describe '#access_retries' do
it 'reads the value from settings' do
expect(circuit_breaker.access_retries).to eq(4)
end
end
describe '#backoff_threshold' do
it 'reads the value from settings' do
expect(circuit_breaker.backoff_threshold).to eq(5)
end
end
end
describe '#perform' do
it 'raises the correct exception when the circuit is open' do
set_in_redis(:last_failure, 1.day.ago.to_f)
set_in_redis(:failure_count, 999)
expect { |b| circuit_breaker.perform(&b) }
.to raise_error do |exception|
expect(exception).to be_kind_of(Gitlab::Git::Storage::CircuitOpen)
expect(exception.retry_after).to eq(1800)
end
end
it 'raises the correct exception when backing off' do
Timecop.freeze do
set_in_redis(:last_failure, 1.second.ago.to_f)
set_in_redis(:failure_count, 90)
expect { |b| circuit_breaker.perform(&b) }
.to raise_error do |exception|
expect(exception).to be_kind_of(Gitlab::Git::Storage::Failing)
expect(exception.retry_after).to eq(30)
end
end
end
it 'yields the block' do
expect { |b| circuit_breaker.perform(&b) }
.to yield_control
end
it 'checks if the storage is available' do
expect(circuit_breaker).to receive(:check_storage_accessible!)
.and_call_original
circuit_breaker.perform { 'hello world' }
end
it 'returns the value of the block' do
result = circuit_breaker.perform { 'return value' }
expect(result).to eq('return value')
end
it 'raises possible errors' do
expect { circuit_breaker.perform { raise Rugged::OSError.new('Broken') } }
.to raise_error(Rugged::OSError)
end
it 'tracks that the storage was accessible' do
set_in_redis(:failure_count, 10)
set_in_redis(:last_failure, Time.now.to_f)
circuit_breaker.perform { '' }
expect(value_from_redis(:failure_count).to_i).to eq(0)
expect(value_from_redis(:last_failure)).to be_empty
expect(circuit_breaker.failure_count).to eq(0)
expect(circuit_breaker.last_failure).to be_nil
end
it 'only performs the accessibility check once' do
expect(Gitlab::Git::Storage::ForkedStorageCheck)
.to receive(:storage_available?).once.and_call_original
2.times { circuit_breaker.perform { '' } }
end
it 'calls the check with the correct arguments' do
stub_application_setting(circuitbreaker_storage_timeout: 30,
circuitbreaker_access_retries: 3)
expect(Gitlab::Git::Storage::ForkedStorageCheck)
.to receive(:storage_available?).with(TestEnv.repos_path, 30, 3)
.and_call_original
circuit_breaker.perform { '' }
end
context 'with the feature disabled' do
before do
stub_feature_flags(git_storage_circuit_breaker: false)
end
it 'returns the block without checking accessibility' do
expect(circuit_breaker).not_to receive(:check_storage_accessible!)
result = circuit_breaker.perform { 'hello' }
expect(result).to eq('hello')
end
it 'allows enabling the feature using an ENV var' do
stub_env('GIT_STORAGE_CIRCUIT_BREAKER', 'true')
expect(circuit_breaker).to receive(:check_storage_accessible!)
result = circuit_breaker.perform { 'hello' }
expect(result).to eq('hello')
end
end
context 'the storage is not available' do
let(:storage_name) { 'broken' }
it 'raises the correct exception' do
expect(circuit_breaker).to receive(:track_storage_inaccessible)
expect { circuit_breaker.perform { '' } }
.to raise_error do |exception|
expect(exception).to be_kind_of(Gitlab::Git::Storage::Inaccessible)
expect(exception.retry_after).to eq(30)
end
end
it 'tracks that the storage was inaccessible' do
Timecop.freeze do
expect { circuit_breaker.perform { '' } }.to raise_error(Gitlab::Git::Storage::Inaccessible)
expect(value_from_redis(:failure_count).to_i).to eq(1)
expect(value_from_redis(:last_failure)).not_to be_empty
expect(circuit_breaker.failure_count).to eq(1)
expect(circuit_breaker.last_failure).to be_within(1.second).of(Time.now)
end
end
end
end
describe '#circuit_broken?' do
it 'is working when there is no last failure' do
set_in_redis(:last_failure, nil)
set_in_redis(:failure_count, 0)
expect(circuit_breaker.circuit_broken?).to be_falsey
end
it 'is broken when there are too many failures' do
set_in_redis(:last_failure, 1.day.ago.to_f)
set_in_redis(:failure_count, 200)
expect(circuit_breaker.circuit_broken?).to be_truthy
end
end
describe '#backing_off?' do
it 'is true when there was a recent failure' do
Timecop.freeze do
set_in_redis(:last_failure, 1.second.ago.to_f)
set_in_redis(:failure_count, 90)
expect(circuit_breaker.backing_off?).to be_truthy
end
end
context 'the `failure_wait_time` is set to 0' do
before do
stub_application_setting(circuitbreaker_failure_wait_time: 0)
end
it 'is working even when there are failures' do
Timecop.freeze do
set_in_redis(:last_failure, 0.seconds.ago.to_f)
set_in_redis(:failure_count, 90)
expect(circuit_breaker.backing_off?).to be_falsey
end
end
end
end
describe '#last_failure' do
it 'returns the last failure time' do
time = Time.parse("2017-05-26 17:52:30")
set_in_redis(:last_failure, time.to_i)
expect(circuit_breaker.last_failure).to eq(time)
end
end
describe '#failure_count' do
it 'returns the failure count' do
set_in_redis(:failure_count, 7)
expect(circuit_breaker.failure_count).to eq(7)
end
end
end
|