Commit cc677c8f authored by Sean McGivern's avatar Sean McGivern Committed by Rémy Coutable

Make UserCohortsService more understandable

1. Extract out into several methods.
2. Add more comments describing the data and the shape of the data.
parent 44f3fc49
class UserCohortsService
def initialize
end
MONTHS_INCLUDED = 12
def execute(months_included)
if Gitlab::Database.postgresql?
created_at_month = "CAST(DATE_TRUNC('month', created_at) AS date)"
current_sign_in_at_month = "CAST(DATE_TRUNC('month', current_sign_in_at) AS date)"
elsif Gitlab::Database.mysql?
created_at_month = "STR_TO_DATE(DATE_FORMAT(created_at, '%Y-%m-01'), '%Y-%m-%d')"
current_sign_in_at_month = "STR_TO_DATE(DATE_FORMAT(current_sign_in_at, '%Y-%m-01'), '%Y-%m-%d')"
end
# Get a hash that looks like:
#
# {
# month => {
# months: [3, 2, 1],
# total: 3
# inactive: 0
# },
# etc.
#
# The `months` array is always from oldest to newest, so it's always
# non-strictly decreasing from left to right.
#
def execute
cohorts = {}
months = Array.new(MONTHS_INCLUDED) { |i| i.months.ago.beginning_of_month.to_date }
counts_by_month =
User
.where('created_at > ?', months_included.months.ago.end_of_month)
.group(created_at_month, current_sign_in_at_month)
.reorder("#{created_at_month} ASC", "#{current_sign_in_at_month} DESC")
.count
MONTHS_INCLUDED.times do
created_at_month = months.last
activity_months = running_totals(months, created_at_month)
cohorts = {}
months = Array.new(months_included) { |i| i.months.ago.beginning_of_month.to_date }
months_included.times do
month = months.last
inactive = counts_by_month[[month, nil]] || 0
# Calculate a running sum of active users, so users active in later months
# count as active in this month, too. Start with the most recent month
# first, for calculating the running totals, and then reverse for
# displaying in the table.
activity_months =
months
.map { |activity_month| counts_by_month[[month, activity_month]] }
.reduce([]) { |result, total| result << result.last.to_i + total.to_i }
.reverse
cohorts[month] = {
# Even if no users registered in this month, we always want to have a
# value to fill in the table.
inactive = counts_by_month[[created_at_month, nil]].to_i
cohorts[created_at_month] = {
months: activity_months,
total: activity_months.first,
inactive: inactive
......@@ -46,4 +37,51 @@ class UserCohortsService
cohorts
end
private
# Calculate a running sum of active users, so users active in later months
# count as active in this month, too. Start with the most recent month first,
# for calculating the running totals, and then reverse for displaying in the
# table.
def running_totals(all_months, created_at_month)
all_months
.map { |activity_month| counts_by_month[[created_at_month, activity_month]] }
.reduce([]) { |result, total| result << result.last.to_i + total.to_i }
.reverse
end
# Get a hash that looks like:
#
# {
# [created_at_month, current_sign_in_at_month] => count,
# [created_at_month, current_sign_in_at_month_2] => count_2,
# # etc.
# }
#
# created_at_month can never be nil, but current_sign_in_at_month can (when a
# user has never logged in, just been created). This covers the last twelve
# months.
#
def counts_by_month
@counts_by_month ||=
begin
created_at_month = column_to_date('created_at')
current_sign_in_at_month = column_to_date('current_sign_in_at_month')
User
.where('created_at > ?', MONTHS_INCLUDED.months.ago.end_of_month)
.group(created_at_month, current_sign_in_at_month)
.reorder("#{created_at_month} ASC", "#{current_sign_in_at_month} ASC")
.count
end
end
def column_to_date(column)
if Gitlab::Database.postgresql?
"CAST(DATE_TRUNC('month', #{column}) AS date)"
elsif Gitlab::Database.mysql?
"STR_TO_DATE(DATE_FORMAT(#{column}, '%Y-%m-01'), '%Y-%m-%d')"
end
end
end
......@@ -32,11 +32,7 @@ describe UserCohortsService do
month_start(0) => { months: [2], total: 2, inactive: 1 }
}
result = described_class.new.execute(12)
expect(result.length).to eq(12)
expect(result.keys).to all(be_a(Date))
expect(result).to eq(expected)
expect(described_class.new.execute).to eq(expected)
end
end
end
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