zeek/scripts/base/frameworks/measurement/main.bro
2013-04-01 14:16:37 -04:00

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##! The metrics framework provides a way to count and measure data.
@load base/utils/queue
module Measurement;
export {
## The various calculations are all defined as plugins.
type Calculation: enum {
PLACEHOLDER
};
## Represents a thing which is having measurement results collected for it.
type Key: record {
## A non-address related metric or a sub-key for an address based metric.
## An example might be successful SSH connections by client IP address
## where the client string would be the key value.
## Another example might be number of HTTP requests to a particular
## value in a Host header. This is an example of a non-host based
## metric since multiple IP addresses could respond for the same Host
## header value.
str: string &optional;
## Host is the value to which this metric applies.
host: addr &optional;
};
## Represents data being added for a single metric data point.
## Only supply a single value here at a time.
type DataPoint: record {
## Count value.
num: count &optional;
## Double value.
dbl: double &optional;
## String value.
str: string &optional;
};
type Reducer: record {
## Data stream identifier for the reducer to attach to.
stream: string;
## The calculations to perform on the data points.
apply: set[Calculation];
## A predicate so that you can decide per key if you would like
## to accept the data being inserted.
pred: function(key: Measurement::Key, point: Measurement::DataPoint): bool &optional;
## A function to normalize the key. This can be used to aggregate or
## normalize the entire key.
normalize_key: function(key: Measurement::Key): Key &optional;
};
## Value calculated for a data point stream fed into a reducer.
## Most of the fields are added by plugins.
type ResultVal: record {
## The time when the first data point was added to this result value.
begin: time;
## The time when the last data point was added to this result value.
end: time;
## The number of measurements received.
num: count &default=0;
};
## Type to store results for multiple reducers.
type Result: table[string] of ResultVal;
## Type to store a table of measurement results indexed by the measurement key.
type ResultTable: table[Key] of Result;
## Measurements represent an aggregation of reducers along with
## mechanisms to handle various situations like the epoch ending
## or thresholds being crossed.
type Measurement: record {
## The interval at which this filter should be "broken" and the
## '$epoch_finished' callback called. The results are also reset
## at this time so any threshold based detection needs to be set to a
## number that should be expected to happen within this epoch.
epoch: interval;
## The reducers for the measurement indexed by data id.
reducers: set[Reducer];
## Provide a function to calculate a value from the :bro:see:`Result`
## structure which will be used for thresholding.
threshold_val: function(key: Measurement::Key, result: Measurement::Result): count &optional;
## The threshold value for calling the $threshold_crossed callback.
threshold: count &optional;
## A series of thresholds for calling the $threshold_crossed callback.
threshold_series: vector of count &optional;
## A callback that is called when a threshold is crossed.
threshold_crossed: function(key: Measurement::Key, result: Measurement::Result) &optional;
## A callback with the full collection of Results for this filter.
## It's best to not access any global state outside of the variables
## given to the callback because there is no assurance provided as to
## where the callback will be executed on clusters.
epoch_finished: function(rt: Measurement::ResultTable) &optional;
};
## Create a measurement.
global create: function(m: Measurement::Measurement);
## Add data into a data point stream. This should be called when
## a script has measured some point value.
##
## id: The stream identifier that the data point represents.
##
## key: The measurement key that the value is to be added to.
##
## point: The data point to send into the stream.
global add_data: function(id: string, key: Measurement::Key, point: Measurement::DataPoint);
## Helper function to represent a :bro:type:`Measurement::Key` value as
## a simple string.
##
## key: The metric key that is to be converted into a string.
##
## Returns: A string representation of the metric key.
global key2str: function(key: Measurement::Key): string;
## This event is generated for each new measurement that is created.
##
## m: The record which describes a measurement.
global new_measurement: event(m: Measurement);
}
redef record Reducer += {
# Internal use only. Provides a reference back to the related Measurement by it's ID.
mid: string &optional;
};
type Thresholding: record {
# Internal use only. Indicates if a simple threshold was already crossed.
is_threshold_crossed: bool &default=F;
# Internal use only. Current key for threshold series.
threshold_series_index: count &default=0;
};
redef record Measurement += {
# Internal use only (mostly for cluster coherency).
id: string &optional;
# Internal use only. For tracking tresholds per key.
threshold_tracker: table[Key] of Thresholding &optional;
};
# Store of measurements indexed on the measurement id.
global measurement_store: table[string] of Measurement = table();
# Store of reducers indexed on the data point stream id.
global reducer_store: table[string] of set[Reducer] = table();
# Store of results indexed on the measurement id.
global result_store: table[string] of ResultTable = table();
# Store of threshold information.
global thresholds_store: table[string, Key] of bool = table();
# This is called whenever
# key values are updated and the new val is given as the `val` argument.
# It's only prototyped here because cluster and non-cluster have separate
# implementations.
global data_added: function(m: Measurement, key: Key, result: Result);
# Prototype the hook point for plugins to do calculations.
global add_to_reducer_hook: hook(r: Reducer, val: double, data: DataPoint, rv: ResultVal);
# Prototype the hook point for plugins to initialize any result values.
global init_resultval_hook: hook(r: Reducer, rv: ResultVal);
# Prototype the hook point for plugins to merge Results.
global compose_resultvals_hook: hook(result: ResultVal, rv1: ResultVal, rv2: ResultVal);
# Event that is used to "finish" measurements and adapt the measurement
# framework for clustered or non-clustered usage.
global finish_epoch: event(m: Measurement);
function key2str(key: Key): string
{
local out = "";
if ( key?$host )
out = fmt("%shost=%s", out, key$host);
if ( key?$str )
out = fmt("%s%sstr=%s", out, |out|==0 ? "" : ", ", key$str);
return fmt("measurement_key(%s)", out);
}
function init_resultval(r: Reducer): ResultVal
{
local rv: ResultVal = [$begin=network_time(), $end=network_time()];
hook init_resultval_hook(r, rv);
return rv;
}
function compose_resultvals(rv1: ResultVal, rv2: ResultVal): ResultVal
{
local result: ResultVal;
# Merge $begin (take the earliest one)
result$begin = (rv1$begin < rv2$begin) ? rv1$begin : rv2$begin;
# Merge $end (take the latest one)
result$end = (rv1$end > rv2$end) ? rv1$end : rv2$end;
# Merge $num
result$num = rv1$num + rv2$num;
hook compose_resultvals_hook(result, rv1, rv2);
return result;
}
function compose_results(r1: Result, r2: Result): Result
{
local result: Result = table();
if ( |r1| > |r2| )
{
for ( data_id in r1 )
{
if ( data_id in r2 )
result[data_id] = compose_resultvals(r1[data_id], r2[data_id]);
else
result[data_id] = r1[data_id];
}
}
else
{
for ( data_id in r2 )
{
if ( data_id in r1 )
result[data_id] = compose_resultvals(r1[data_id], r2[data_id]);
else
result[data_id] = r2[data_id];
}
}
return result;
}
function reset(m: Measurement)
{
if ( m$id in result_store )
delete result_store[m$id];
result_store[m$id] = table();
}
function create(m: Measurement)
{
if ( ! m?$id )
m$id=unique_id("");
local tmp: table[Key] of Thresholding = table();
m$threshold_tracker = tmp;
measurement_store[m$id] = m;
for ( reducer in m$reducers )
{
reducer$mid = m$id;
if ( reducer$stream !in reducer_store )
reducer_store[reducer$stream] = set();
add reducer_store[reducer$stream][reducer];
}
reset(m);
schedule m$epoch { Measurement::finish_epoch(m) };
}
function add_data(id: string, key: Key, point: DataPoint)
{
# Try to add the data to all of the defined reducers.
if ( id !in reducer_store )
return;
for ( r in reducer_store[id] )
{
# If this reducer has a predicate, run the predicate
# and skip this key if the predicate return false.
if ( r?$pred && ! r$pred(key, point) )
next;
if ( r?$normalize_key )
key = r$normalize_key(copy(key));
local m = measurement_store[r$mid];
local results = result_store[m$id];
if ( key !in results )
results[key] = table();
if ( id !in results[key] )
results[key][id] = init_resultval(r);
local result = results[key];
local result_val = result[id];
++result_val$num;
# Continually update the $end field.
result_val$end=network_time();
# If a string was given, fall back to 1.0 as the value.
local val = 1.0;
if ( point?$num || point?$dbl )
val = point?$dbl ? point$dbl : point$num;
hook add_to_reducer_hook(r, val, point, result_val);
data_added(m, key, result);
}
}
# This function checks if a threshold has been crossed. It is also used as a method to implement
# mid-break-interval threshold crossing detection for cluster deployments.
function check_thresholds(m: Measurement, key: Key, result: Result, modify_pct: double): bool
{
if ( ! (m?$threshold || m?$threshold_series) )
return F;
if ( key !in m$threshold_tracker )
{
local tmp: Thresholding;
m$threshold_tracker[key] = tmp;
}
# Add in the extra ResultVals to make threshold_vals easier to write.
if ( |m$reducers| != |result| )
{
for ( reducer in m$reducers )
{
if ( reducer$stream !in result )
result[reducer$stream] = init_resultval(reducer);
}
}
local watch = m$threshold_val(key, result);
if ( modify_pct < 1.0 && modify_pct > 0.0 )
watch = double_to_count(floor(watch/modify_pct));
local tt = m$threshold_tracker[key];
if ( m?$threshold && ! tt$is_threshold_crossed && watch >= m$threshold )
{
# Value crossed the threshold.
return T;
}
if ( m?$threshold_series &&
|m$threshold_series| >= tt$threshold_series_index &&
watch >= m$threshold_series[tt$threshold_series_index] )
{
# A threshold series was given and the value crossed the next
# value in the series.
return T;
}
return F;
}
function threshold_crossed(m: Measurement, key: Key, result: Result)
{
# If there is no callback, there is no point in any of this.
if ( ! m?$threshold_crossed )
return;
#if ( val?$sample_queue )
# val$samples = Queue::get_str_vector(val$sample_queue);
# Add in the extra ResultVals to make threshold_crossed callbacks easier to write.
if ( |m$reducers| != |result| )
{
for ( reducer in m$reducers )
{
if ( reducer$stream !in result )
result[reducer$stream] = init_resultval(reducer);
}
}
m$threshold_crossed(key, result);
local tt = m$threshold_tracker[key];
tt$is_threshold_crossed = T;
# Bump up to the next threshold series index if a threshold series is being used.
if ( m?$threshold_series )
++tt$threshold_series_index;
}