Send SimpleCov or CodeClimate test coverage summary metrics to Datadog

send_coverage_summary_to_dd.rb

# /usr/bin/env ruby

begin
  require "git"
  require "datadog_api_client"
rescue LoadError
  Gem.install "git"
  Gem.install "datadog_api_client"

  require "git"
  require "datadog_api_client"
end

# Read the app name from CircleCI project environment variables
# https://circleci.com/docs/variables
APP_NAME = ENV.fetch("CIRCLE_PROJECT_REPONAME").freeze

if File.file?(".codeclimate/codeclimate.json")
  summary = JSON.parse(File.read(".codeclimate/codeclimate.json"))
  line_coverage_percent = summary["covered_percent"]
elsif File.file?("coverage/.last_run.json")
  # Read SimpleCov coverage summary results
  summary = JSON.parse(File.read("coverage/.last_run.json"))
  line_coverage_percent = summary["result"]["line"]
  branch_coverage_percent = summary["result"]["branch"]
else
  raise "Could not find coverage file!"
end

# Read timestamp of latest commit
git = Git.open(".")
last_commit_timestamp = git.log.first.author_date

# Send line coverage metric to Datadog
# https://docs.datadoghq.com/api/latest/metrics/?code-lang=ruby

# These are used internally by DatadogAPIClient so throw an error if they are not set.
ENV.fetch("DD_API_KEY")
ENV["DD_SITE"] ||= "datadoghq.com"

METRIC_NAME = "test.coverage.line".freeze

api_instance = DatadogAPIClient::V2::MetricsAPI.new

body = DatadogAPIClient::V2::MetricPayload.new({
  series: [
    DatadogAPIClient::V2::MetricSeries.new({
      metric: METRIC_NAME,
      type: DatadogAPIClient::V2::MetricIntakeType::GAUGE,
      points: [
        DatadogAPIClient::V2::MetricPoint.new({
          timestamp: last_commit_timestamp.to_i,
          value: line_coverage_percent
        }),
      ],
      resources: [
        DatadogAPIClient::V2::MetricResource.new({
          name: APP_NAME,
          type: "host",
        }),
      ],
      tags: [
        "branch:#{git.current_branch}"
      ]
    }),
  ],
})

# Should we only send this on the main branch?
puts "\nSending metrics:", body, ""

response = api_instance.submit_metrics(body)

case response
when DatadogAPIClient::V2::IntakePayloadAccepted
  puts "OK"
else
  raise RuntimeError, response.inspect
end


##
# Query metrics to find the highest recent coverage from main and compare current
# Should we skip this on the main branch?
#
ENV.fetch("DD_APP_KEY") # This is required to query metrics

api_instance = DatadogAPIClient::V1::MetricsAPI.new

time_1_week_ago = Time.now - (60*60*24*7)
metrics_response = api_instance.query_metrics(time_1_week_ago.to_i, Time.now.to_i, "max:#{METRIC_NAME}{branch:main,host:#{APP_NAME}}")
historic_coverage_percentages = metrics_response.series.first.pointlist.map(&:last)
last_highest_coverage_percent = historic_coverage_percentages.max

if line_coverage_percent < last_highest_coverage_percent
  raise "😖 Line code coverage fell! #{line_coverage_percent}% < #{last_highest_coverage_percent}%"
elsif line_coverage_percent == last_highest_coverage_percent
  puts "👍 Line code coverage is unchanged at #{line_coverage_percent}%"
else
  difference = line_coverage_percent - last_highest_coverage_percent
  puts "🚀 Line code coverage increased #{difference}% to #{line_coverage_percent}%"
end