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discourse/spec/services/admin_dashboard_section_loader_spec.rb
Krzysztof Kotlarek ad472d1ca2
FIX: Return database connections to the pool after dashboard builds (#41583)
Previously, AdminDashboardSectionLoader worker threads leased a database
connection on their first query and held it while idling in the shared
thread pool, which exhausted the connection pool (sized 5 in
development) and made subsequent requests fail with "could not obtain a
connection from the pool within 5.000 seconds".

This change wraps each section build in
ActiveRecord::Base.with_connection(prevent_permanent_checkout: true) so
the connection is checked back in as soon as the section finishes
building - the flag is required because sections use
ActiveRecord::Base.connection internally, which would otherwise mark the
connection as permanently checked out for the thread. The regression
spec lives in a separate describe block with use_transactional_tests =
false because both transactional tests and fab!'s before(:all)
transaction pin a single shared connection across threads, which masks
the leak.
2026-07-10 09:54:40 +08:00

137 lines
4.3 KiB
Ruby
Vendored

# frozen_string_literal: true
describe AdminDashboardSectionLoader do
fab!(:admin)
after do
if thread_pool = described_class.instance_variable_get(:@thread_pool)
thread_pool.shutdown
thread_pool.wait_for_termination(timeout: 1)
described_class.remove_instance_variable(:@thread_pool)
end
end
describe ".build" do
it "ensures the sections are built in order with current user and dates" do
AdminDashboardSiteTraffic
.expects(:build)
.with do |kwargs|
kwargs[:start_date] == "2026-05-01" && kwargs[:end_date] == "2026-05-07" &&
kwargs[:guardian].is_a?(Guardian) && kwargs[:guardian].user.id == admin.id
end
.returns({ value: "traffic" })
AdminDashboardEngagement
.expects(:build)
.with(start_date: "2026-05-01", end_date: "2026-05-07", current_user: admin)
.returns({ value: "engagement" })
AdminDashboardSearch
.expects(:build)
.with(start_date: "2026-05-01", end_date: "2026-05-07")
.returns({ value: "search" })
expect(
described_class.build(
section_ids: %w[traffic engagement search],
current_user: admin,
start_date: "2026-05-01",
end_date: "2026-05-07",
),
).to eq(
[
{ id: "traffic", data: { value: "traffic" } },
{ id: "engagement", data: { value: "engagement" } },
{ id: "search", data: { value: "search" } },
],
)
end
end
describe "plugin sections" do
it "routes a registered plugin section id to its loader block" do
loader = ->(start_date:, end_date:, current_user:) do
{ value: "support", user: current_user.id }
end
DiscoursePluginRegistry.stubs(:admin_dashboard_sections).returns(
[{ id: "support", enabled: -> { true }, loader: loader }],
)
expect(
described_class.build(
section_ids: ["support"],
current_user: admin,
start_date: "2026-05-01",
end_date: "2026-05-07",
),
).to eq([{ id: "support", data: { value: "support", user: admin.id } }])
end
it "returns nil data for an unknown section id" do
DiscoursePluginRegistry.stubs(:admin_dashboard_sections).returns([])
expect(
described_class.build(
section_ids: ["frobnitz"],
current_user: admin,
start_date: "2026-05-01",
end_date: "2026-05-07",
),
).to eq([{ id: "frobnitz", data: nil }])
end
end
describe ".pool_size" do
it "caps at the DB connection pool, reserving one for the request thread" do
ActiveRecord::Base.connection_pool.stubs(:size).returns(3)
expect(described_class.pool_size).to eq(2)
end
it "uses the desired count when the pool has room to spare" do
ActiveRecord::Base.connection_pool.stubs(:size).returns(100)
desired =
AdminDashboardSectionConfiguration::KNOWN_SECTIONS.size +
DiscoursePluginRegistry.admin_dashboard_sections.size
expect(described_class.pool_size).to eq(desired)
end
it "never drops below one" do
ActiveRecord::Base.connection_pool.stubs(:size).returns(1)
expect(described_class.pool_size).to eq(1)
end
end
end
describe AdminDashboardSectionLoader do
self.use_transactional_tests = false
after do
if thread_pool = described_class.instance_variable_get(:@thread_pool)
thread_pool.shutdown
thread_pool.wait_for_termination(timeout: 1)
described_class.remove_instance_variable(:@thread_pool)
end
end
it "returns database connections to the pool once a section finishes building" do
worker_thread = nil
loader = ->(start_date:, end_date:, current_user:) do
worker_thread = Thread.current
ActiveRecord::Base.connection.execute("SELECT 1")
{ value: "leaky" }
end
DiscoursePluginRegistry.stubs(:admin_dashboard_sections).returns(
[{ id: "leaky", enabled: -> { true }, loader: loader }],
)
described_class.build(
section_ids: ["leaky"],
current_user: Discourse.system_user,
start_date: "2026-05-01",
end_date: "2026-05-07",
)
expect(worker_thread).not_to eq(Thread.current)
wait_for do
ActiveRecord::Base.connection_pool.connections.none? { |c| c.owner == worker_thread }
end
end
end