module Mmtrix::Agent::Datastores

This module contains helper methods to facilitate instrumentation of datastores not directly supported by the Ruby agent. It is intended to be primarily used by authors of 3rd-party datastore instrumentation.

@api public

Public Class Methods

notice_sql(query, scoped_metric, elapsed) click to toggle source

Wrapper for simplifying attaching SQL queries during a transaction.

If you are recording non-SQL data, please use {notice_statement} instead.

Mmtrix::Agent::Datastores.notice_sql(query, metrics, elapsed)

@param [String] query the SQL text to be captured. Note that depending

on user settings, this string will be run through obfuscation, but
some dialects of SQL (or non-SQL queries) are not guaranteed to be
properly obfuscated by these routines!

@param [String] scoped_metric The most specific metric relating to this

query. Typically the result of
Mmtrix::Agent::Datastores::MetricHelper#metrics_for

@param [Float] elapsed the elapsed time during query execution

@note THERE ARE SECURITY CONCERNS WHEN CAPTURING QUERY TEXT!

Mmtrix's Transaction Tracing and Slow SQL features will
attempt to apply obfuscation to the passed queries, but it is possible
for a query format to be unsupported and result in exposing user
information embedded within captured queries.

@api public

# File lib/mmtrix/agent/datastores.rb, line 149
def self.notice_sql(query, scoped_metric, elapsed)
  agent = Mmtrix::Agent.instance
  agent.transaction_sampler.notice_sql(query, nil, elapsed)
  agent.sql_sampler.notice_sql(query, scoped_metric, nil, elapsed)
  nil
end
notice_statement(statement, elapsed) click to toggle source

Wrapper for simplifying attaching non-SQL data statements to a transaction. For instance, Mongo or CQL queries, Memcached or Redis keys would all be appropriate data to attach as statements.

Data passed to this method is NOT obfuscated by Mmtrix, so please ensure that user information is obfuscated if the agent setting ‘transaction_tracer.record_sql` is set to `obfuscated`

Mmtrix::Agent::Datastores.notice_statement("key", elapsed)

@param [String] statement text of the statement to capture.

@param [Float] elapsed the elapsed time during query execution

@note THERE ARE SECURITY CONCERNS WHEN CAPTURING STATEMENTS!

This method will properly ignore statements when the user has turned
off capturing queries, but it is not able to obfuscate arbitrary data!
To prevent exposing user information embedded in captured queries,
please ensure all data passed to this method is safe to transmit to
Mmtrix.

@api public

# File lib/mmtrix/agent/datastores.rb, line 179
def self.notice_statement(statement, elapsed)
  # Settings may change eventually, but for now we follow the same
  # capture rules as SQL for non-SQL statements.
  return unless Mmtrix::Agent::Database.should_record_sql?

  agent = Mmtrix::Agent.instance
  agent.transaction_sampler.notice_nosql_statement(statement, elapsed)
  nil
end
trace(clazz, method_name, product, operation = method_name) click to toggle source

Add Datastore tracing to a method. This properly generates the metrics for Mmtrix’s Datastore features. It does not capture the actual query content into Transaction Traces. Use wrap if you want to provide that functionality.

@param [Class] clazz the class to instrument

@param [String, Symbol] method_name the name of instance method to

instrument

@param [String] product name of your datastore for use in metric naming, e.g. “Redis”

@param [optional,String] operation the name of operation if different

than the instrumented method name

@api public

# File lib/mmtrix/agent/datastores.rb, line 36
def self.trace(clazz, method_name, product, operation = method_name)
  clazz.class_eval do
    method_name_without_mmtrix = "#{method_name}_without_mmtrix"

    if Mmtrix::Helper.instance_methods_include?(clazz, method_name) &&
       !Mmtrix::Helper.instance_methods_include?(clazz, method_name_without_mmtrix)

      visibility = Mmtrix::Helper.instance_method_visibility(clazz, method_name)

      alias_method method_name_without_mmtrix, method_name

      define_method(method_name) do |*args, &blk|
        metrics = MetricHelper.metrics_for(product, operation)
        Mmtrix::Agent::MethodTracer.trace_execution_scoped(metrics) do
          send(method_name_without_mmtrix, *args, &blk)
        end
      end

      send visibility, method_name
      send visibility, method_name_without_mmtrix
    end
  end
end
wrap(product, operation, collection = nil, callback = nil) { || ... } click to toggle source

Wrap a call to a datastore and record Mmtrix Datastore metrics. This method can be used when a collection (i.e. table or model name) is known at runtime to be included in the metric naming. It is intended for situations that the simpler Mmtrix::Agent::Datastores.trace can’t properly handle.

To use this, wrap the datastore operation in the block passed to wrap.

Mmtrix::Agent::Datastores.wrap("FauxDB", "find", "items") do
  FauxDB.find(query)
end

@param [String] product the datastore name for use in metric naming,

e.g. "FauxDB"

@param [String,Symbol] operation the name of operation (e.g. “select”),

often named after the method that's being instrumented.

@param [optional, String] collection the collection name for use in

statement-level metrics (i.e. table or model name)

@param [Proc,#call] callback proc or other callable to invoke after

running the datastore block. Receives three arguments: result of the
yield, the most specific (scoped) metric name, and elapsed time of the
call. An example use is attaching SQL to Transaction Traces at the end
of a wrapped datastore call.

  callback = Proc.new do |result, metrics, elapsed|
    Mmtrix::Agent::Datastores.notice_sql(query, metrics, elapsed)
  end

  Mmtrix::Agent::Datastores.wrap("FauxDB", "find", "items", callback) do
    FauxDB.find(query)
  end

@note THERE ARE SECURITY CONCERNS WHEN CAPTURING QUERY TEXT!

Mmtrix's Transaction Tracing and Slow SQL features will
attempt to apply obfuscation to the passed queries, but it is possible
for a query format to be unsupported and result in exposing user
information embedded within captured queries.

@api public

# File lib/mmtrix/agent/datastores.rb, line 103
def self.wrap(product, operation, collection = nil, callback = nil)
  return yield unless operation

  metrics = MetricHelper.metrics_for(product, operation, collection)
  scoped_metric = metrics.first
  Mmtrix::Agent::MethodTracer.trace_execution_scoped(metrics) do
    t0 = Time.now
    begin
      result = yield
    ensure
      if callback
        elapsed_time = (Time.now - t0).to_f
        callback.call(result, scoped_metric, elapsed_time)
      end
    end
  end
end