From b75c62086f4bb49bd1fbe08ce5b6d6e88a45421a Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Wed, 22 Jan 2025 18:57:34 +0000
Subject: [PATCH] builders: Add helper function to find the least busy builders

This works out a little bit easier than fetching the job queue for each
individual builder.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/buildservice/builders.py | 52 ++++++++++++++++++++++++++++++++++++
 src/buildservice/jobs.py     | 21 ++++-----------
 2 files changed, 57 insertions(+), 16 deletions(-)

diff --git a/src/buildservice/builders.py b/src/buildservice/builders.py
index fd2930fa..074919ac 100644
--- a/src/buildservice/builders.py
+++ b/src/buildservice/builders.py
@@ -211,6 +211,58 @@ class Builders(base.Object):
 
 		return await self.db.fetch_one(stmt)
 
+	@property
+	def least_busy(self):
+		"""
+			Returns all builders in order of busyness (i.e. running the least jobs)
+		"""
+		builder_jobs = (
+			sqlalchemy
+			.select(
+				Builder.id.label("builder_id"),
+				sqlalchemy.func.count().label("running_jobs"),
+			)
+			.join(
+				jobs.Job,
+				jobs.Job.builder_id == Builder.id,
+			)
+			.where(
+				# Jobs cannot be deleted
+				jobs.Job.deleted_at == None,
+
+				# Jobs must be running
+				jobs.Job.started_at != None,
+				jobs.Job.finished_at == None,
+			)
+			.group_by(
+				Builder.id,
+			)
+			.cte("builder_jobs")
+		)
+
+		stmt = (
+			sqlalchemy
+			.select(
+				Builder,
+			)
+			.select_from(
+				builder_jobs,
+			)
+			.join(
+				Builder,
+				Builder.id == builder_jobs.c.builder_id,
+			)
+			.order_by(
+				(
+					builder_jobs.c.running_jobs
+					/
+					Builder.max_jobs
+				).asc(),
+			)
+		)
+
+		return self.db.fetch(stmt)
+
 	async def autoscale(self, wait=False):
 		"""
 			This method performs two tasks:
diff --git a/src/buildservice/jobs.py b/src/buildservice/jobs.py
index faf5245c..4f7fb223 100644
--- a/src/buildservice/jobs.py
+++ b/src/buildservice/jobs.py
@@ -307,35 +307,24 @@ class Queue(base.Object):
 			# Clear the request
 			self._dispatch_requested.clear()
 
-			builders = []
+			builders = queue.SimpleQueue()
 
 			# Add all builders to the queue in ascending order of running jobs
-			async for builder in self.backend.builders:
+			async for builder in self.backend.builders.least_busy:
 				# Skip any builders that are not enabled
 				if not builder.enabled:
 					continue
 
 				# Skip any builders that are not connected
-				elif not builder.is_connected():
+				elif not builder.is_online():
 					continue
 
 				# Skip any builders that are already full
 				elif builder.is_full():
 					continue
 
-				# Fetch all jobs this builder is currently running
-				jobs = await builder.get_jobs()
-
-				# Add the builder to the list and include the number of running jobs
-				builders.append(
-					len(jobs), builder,
-				)
-
-			# Create a queue for all builders and put those
-			# that have the fewest jobs at the beginning.
-			builders = queue.SimpleQueue(
-				[builder for jobs, builder in sorted(builders)],
-			)
+				# Add it to the queue
+				builders.put(builder)
 
 			# Run for as long as we have unprocessed builders
 			while not builders.empty():
-- 
2.47.3