Class: Batsd::Redis
- Inherits:
-
Object
- Object
- Batsd::Redis
- Defined in:
- lib/batsd/redis.rb
Overview
This is a thin wrapper around the redis client to handle multistep procedures that could be executed using Redis scripting
Instance Method Summary (collapse)
-
- (Object) add_datapoint(key)
Stores a reference to the datapoint in the 'datapoints' set.
-
- (Object) client
Expose the redis client directly.
-
- (Object) datapoints(with_gauges = true)
Convenience accessor to members of datapoints set.
-
- (Object) extract_values_from_string(key)
Create an array out of a string of values delimited by <X>.
-
- (Object) get_and_clear_key(key)
Returns the value of a key and then deletes it.
-
- (Redis) initialize(options)
constructor
Opens a new connection to the redis instance specified in the configuration or localhost:6379.
-
- (Object) store_and_update_all_counters(timestamp, key, value)
Store a counter measurement for each of the specified retentions.
-
- (Object) store_raw_timers_for_aggregations(key, values)
Store unaggregated, raw timer values in bucketed keys so that they can actually be aggregated "raw".
-
- (Object) store_timer(timestamp, key, value)
Store a timer to a zset.
-
- (Object) truncate_zset(key, since)
Truncate a zset since a treshold time.
-
- (Object) values_from_zset(metric, begin_ts, end_ts)
Return properly formatted values from the zset.
Constructor Details
- (Redis) initialize(options)
Opens a new connection to the redis instance specified in the configuration or localhost:6379
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# File 'lib/batsd/redis.rb', line 12 def initialize() @redis = ::Redis.new([:redis] || {host: "127.0.0.1", port: 6379} ) @redis.ping @retentions = [:retentions].keys end |
Instance Method Details
- (Object) add_datapoint(key)
Stores a reference to the datapoint in the 'datapoints' set
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# File 'lib/batsd/redis.rb', line 125 def add_datapoint(key) @redis.sadd "datapoints", key end |
- (Object) client
Expose the redis client directly
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# File 'lib/batsd/redis.rb', line 19 def client @redis end |
- (Object) datapoints(with_gauges = true)
Convenience accessor to members of datapoints set
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# File 'lib/batsd/redis.rb', line 114 def datapoints(with_gauges=true) datapoints = @redis.smembers "datapoints" unless with_gauges datapoints.reject!{|d| (d.match(/^gauge/) rescue false) } end datapoints end |
- (Object) extract_values_from_string(key)
Create an array out of a string of values delimited by <X>
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# File 'lib/batsd/redis.rb', line 79 def extract_values_from_string(key) cmd = "local t={} ; local i=1\nlocal str = redis.call('get', KEYS[1])\nif (str) then\nfor s in string.gmatch(str, \"([^\"..\"<X>\"..\"]+)\") do\nt[i] = s\ni = i + 1\nend\nredis.call('del', KEYS[1])\nend\nreturn t\n" @redis.eval(cmd, 1, key.to_sym) end |
- (Object) get_and_clear_key(key)
Returns the value of a key and then deletes it.
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# File 'lib/batsd/redis.rb', line 68 def get_and_clear_key(key) cmd = "local str = redis.call('get', KEYS[1])\nredis.call('del', KEYS[1])\nreturn str\n" @redis.eval(cmd, 1, key.to_sym) end |
- (Object) store_and_update_all_counters(timestamp, key, value)
Store a counter measurement for each of the specified retentions
-
For shortest retention (where timestep == flush interval), add the value and timestamp to the appropriate zset
-
For longer retention intervals, increment the appropriate counter by the value specified.
TODO: This can be done in a single network request by rewriting it as a redis script in Lua
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# File 'lib/batsd/redis.rb', line 34 def store_and_update_all_counters(, key, value) @retentions.each_with_index do |t, index| if index.zero? @redis.zadd key, , "#{timestamp}<X>#{value}" else index.zero? @redis.incrby "#{key}:#{t}", value @redis.expire "#{key}:#{t}", t.to_i * 2 end end end |
- (Object) store_raw_timers_for_aggregations(key, values)
Store unaggregated, raw timer values in bucketed keys so that they can actually be aggregated "raw"
The set of tiemrs are stored as a single string key delimited by x0. In benchmarks, this is more efficient in memory by 2-3x, and less efficient in time by ~10%
TODO: can this be done more efficiently with redis scripting?
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# File 'lib/batsd/redis.rb', line 59 def store_raw_timers_for_aggregations(key, values) @retentions.each_with_index do |t, index| next if index.zero? @redis.append "#{key}:#{t}", "<X>#{values.join("<X>")}" @redis.expire "#{key}:#{t}", t.to_i * 2 end end |
- (Object) store_timer(timestamp, key, value)
Store a timer to a zset
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# File 'lib/batsd/redis.rb', line 47 def store_timer(, key, value) @redis.zadd key, , "#{timestamp}<X>#{value}" end |
- (Object) truncate_zset(key, since)
Truncate a zset since a treshold time
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# File 'lib/batsd/redis.rb', line 98 def truncate_zset(key, since) @redis.zremrangebyscore key, 0, since end |
- (Object) values_from_zset(metric, begin_ts, end_ts)
Return properly formatted values from the zset
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# File 'lib/batsd/redis.rb', line 103 def values_from_zset(metric, begin_ts, end_ts) begin values = @redis.zrangebyscore(metric, begin_ts, end_ts) values.collect{|val| ts, val = val.split("<X>"); {: ts, value: val } } rescue [] end end |