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
|
# frozen_string_literal: true
module Gitlab
module Cache
module Import
module Caching
# The default timeout of the cache keys.
TIMEOUT = 24.hours.to_i
LONGER_TIMEOUT = 72.hours.to_i
SHORTER_TIMEOUT = 15.minutes.to_i
WRITE_IF_GREATER_SCRIPT = <<-EOF.strip_heredoc.freeze
local key, value, ttl = KEYS[1], tonumber(ARGV[1]), ARGV[2]
local existing = tonumber(redis.call("get", key))
if existing == nil or value > existing then
redis.call("set", key, value)
redis.call("expire", key, ttl)
return true
else
return false
end
EOF
# Reads a cache key.
#
# If the key exists and has a non-empty value its TTL is refreshed
# automatically.
#
# raw_key - The cache key to read.
# timeout - The new timeout of the key if the key is to be refreshed.
def self.read(raw_key, timeout: TIMEOUT)
key = cache_key_for(raw_key)
value = Redis::Cache.with { |redis| redis.get(key) }
if value.present?
# We refresh the expiration time so frequently used keys stick
# around, removing the need for querying the database as much as
# possible.
#
# A key may be empty when we looked up a GitHub user (for example) but
# did not find a matching GitLab user. In that case we _don't_ want to
# refresh the TTL so we automatically pick up the right data when said
# user were to register themselves on the GitLab instance.
Redis::Cache.with { |redis| redis.expire(key, timeout) }
end
value
end
# Reads an integer from the cache, or returns nil if no value was found.
#
# See Caching.read for more information.
def self.read_integer(raw_key, timeout: TIMEOUT)
value = read(raw_key, timeout: timeout)
value.to_i if value.present?
end
# Sets a cache key to the given value.
#
# raw_key - The cache key to write.
# value - The value to set.
# timeout - The time after which the cache key should expire.
def self.write(raw_key, value, timeout: TIMEOUT)
validate_redis_value!(value)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.set(key, value, ex: timeout)
end
value
end
# Increment the integer value of a key by one.
# Sets the value to zero if missing before incrementing
#
# raw_key - The cache key to increment.
# timeout - The time after which the cache key should expire.
# @return - the incremented value
def self.increment(raw_key, timeout: TIMEOUT)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
value = redis.incr(key)
redis.expire(key, timeout)
value
end
end
# Increment the integer value of a key by the given value.
# Sets the value to zero if missing before incrementing
#
# raw_key - The cache key to increment.
# value - The value to increment the key
# timeout - The time after which the cache key should expire.
# @return - the incremented value
def self.increment_by(raw_key, value, timeout: TIMEOUT)
validate_redis_value!(value)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.incrby(key, value)
redis.expire(key, timeout)
end
end
# Adds a value to a set.
#
# raw_key - The key of the set to add the value to.
# value - The value to add to the set.
# timeout - The new timeout of the key.
def self.set_add(raw_key, value, timeout: TIMEOUT)
validate_redis_value!(value)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.multi do |m|
m.sadd(key, value)
m.expire(key, timeout)
end
end
end
# Returns true if the given value is present in the set.
#
# raw_key - The key of the set to check.
# value - The value to check for.
def self.set_includes?(raw_key, value)
validate_redis_value!(value)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.sismember(key, value)
end
end
# Returns the values of the given set.
#
# raw_key - The key of the set to check.
def self.values_from_set(raw_key)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.smembers(key)
end
end
# Sets multiple keys to given values.
#
# mapping - A Hash mapping the cache keys to their values.
# key_prefix - prefix inserted before each key
# timeout - The time after which the cache key should expire.
def self.write_multiple(mapping, key_prefix: nil, timeout: TIMEOUT)
Redis::Cache.with do |redis|
redis.pipelined do |multi|
mapping.each do |raw_key, value|
key = cache_key_for("#{key_prefix}#{raw_key}")
validate_redis_value!(value)
multi.set(key, value, ex: timeout)
end
end
end
end
# Sets the expiration time of a key.
#
# raw_key - The key for which to change the timeout.
# timeout - The new timeout.
def self.expire(raw_key, timeout)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.expire(key, timeout)
end
end
# Sets a key to the given integer but only if the existing value is
# smaller than the given value.
#
# This method uses a Lua script to ensure the read and write are atomic.
#
# raw_key - The key to set.
# value - The new value for the key.
# timeout - The key timeout in seconds.
#
# Returns true when the key was overwritten, false otherwise.
def self.write_if_greater(raw_key, value, timeout: TIMEOUT)
validate_redis_value!(value)
key = cache_key_for(raw_key)
val = Redis::Cache.with do |redis|
redis
.eval(WRITE_IF_GREATER_SCRIPT, keys: [key], argv: [value, timeout])
end
val ? true : false
end
# Adds a value to a hash.
#
# raw_key - The key of the hash to add to.
# field - The field to add to the hash.
# value - The field value to add to the hash.
# timeout - The new timeout of the key.
def self.hash_add(raw_key, field, value, timeout: TIMEOUT)
validate_redis_value!(value)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.multi do |m|
m.hset(key, field, value)
m.expire(key, timeout)
end
end
end
# Returns the values of the given hash.
#
# raw_key - The key of the set to check.
def self.values_from_hash(raw_key)
key = cache_key_for(raw_key)
Redis::Cache.with do |redis|
redis.hgetall(key)
end
end
def self.cache_key_for(raw_key)
"#{Redis::Cache::CACHE_NAMESPACE}:#{raw_key}"
end
def self.validate_redis_value!(value)
value_as_string = value.to_s
return if value_as_string.is_a?(String)
raise "Value '#{value_as_string}' of type '#{value_as_string.class}' for '#{value.inspect}' is not a String"
end
end
end
end
end
|