Removing stale metrics from Librato

remove_stale_metrics.rb

#!/usr/bin/env ruby

require 'librato/metrics'

c = Librato::Metrics

email = 'user@example.com'
token = 'abcd1234'

c.authenticate email, token

# Threshold to check for "last reported" time
days_ago = 30

# Calculate the timestamp from X days ago
time_cutoff = Time.now.to_i - (days_ago * 24 * 3600)
# Floor the time to the nearest hour
time_cutoff = time_cutoff - time_cutoff % 3600

results = []

# NOTE: if you have a lot of metrics, this could take quite a while to run!
# The metrics listing occurs in pages of 100 at a time, so if you have 20,000 metrics, that's
# 200 pages that get stored in memory
# Assume up to 500ms to get the last measurement as well.
name_filter = '' # Set this to limit the result set to a certain pattern, like 'abc' or 'abc*'
c.metrics(name: name_filter).each do |m|
  next if m['type'] == 'composite'
  metric_name = m['name']
  if c.get_measurements(metric_name, start_time: time_cutoff,
resolution: 3600, count: 1).empty?
    # Metric hasn't reported since X days ago
    puts metric_name
    results << metric_name
  end
end

puts "Found #{results.size} metrics not reporting in #{days_ago} days (since #{Time.at(time_cutoff)}):"

# Delete 10 at a time, probably safe for up to 100
#results.each_slice(10) do |metric_names|
#  puts "Deleting #{metric_names}..."
  # Need to splat this so you get a list of args vs just the array
  # Uncomment this to actually do the deletes
  #c.delete_metrics(*metric_names)
  #puts "done."
#end

Nice script! I was getting a bad request error on the get_measurements call for some metrics but fixed it by adding this right before it:

next if m['type'] == 'composite'

good catch