20978: Rearrange large if-else sequence for clarity.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>

diff --git a/lib/dispatchcloud/scheduler/run_queue.go b/lib/dispatchcloud/scheduler/run_queue.go
index 8264c5ef0a3df0be5736fa388b3e1736768fc466..2f1f17589029dfea32f2a44ac25f0a65f0ee017e 100644 (file)
--- a/lib/dispatchcloud/scheduler/run_queue.go
+++ b/lib/dispatchcloud/scheduler/run_queue.go
@@ -235,9 +235,28 @@ tryrun:
                        }
                        trying++
                        if unallocOK {
+                               // We have a suitable instance type,
+                               // so mark it as allocated, and try to
+                               // start the container.
                                unalloc[unallocType]--
                                logger = logger.WithField("InstanceType", unallocType)
-                       } else if sch.pool.AtQuota() {
+                               if dontstart[unallocType] {
+                                       // We already tried & failed to start
+                                       // a higher-priority container on the
+                                       // same instance type. Don't let this
+                                       // one sneak in ahead of it.
+                               } else if sch.pool.KillContainer(ctr.UUID, "about to start") {
+                                       logger.Info("not restarting yet: crunch-run process from previous attempt has not exited")
+                               } else if sch.pool.StartContainer(unallocType, ctr) {
+                                       logger.Trace("StartContainer => true")
+                               } else {
+                                       logger.Trace("StartContainer => false")
+                                       containerAllocatedWorkerBootingCount += 1
+                                       dontstart[unallocType] = true
+                               }
+                               continue
+                       }
+                       if sch.pool.AtQuota() {
                                // Don't let lower-priority containers
                                // starve this one by using keeping
                                // idle workers alive on different
@@ -245,7 +264,8 @@ tryrun:
                                logger.Trace("overquota")
                                overquota = sorted[i:]
                                break tryrun
-                       } else if !availableOK {
+                       }
+                       if !availableOK {
                                // Continue trying lower-priority
                                // containers in case they can run on
                                // different instance types that are
@@ -261,40 +281,24 @@ tryrun:
                                // container B now.
                                logger.Trace("all eligible types at capacity")
                                continue
-                       } else if logger = logger.WithField("InstanceType", availableType); sch.pool.Create(availableType) {
-                               // Success. (Note pool.Create works
-                               // asynchronously and does its own
-                               // logging about the eventual outcome,
-                               // so we don't need to.)
-                               logger.Info("creating new instance")
-                               // Don't bother trying to start the
-                               // container yet -- obviously the
-                               // instance will take some time to
-                               // boot and become ready.
-                               containerAllocatedWorkerBootingCount += 1
-                               dontstart[availableType] = true
-                               continue
-                       } else {
+                       }
+                       logger = logger.WithField("InstanceType", availableType)
+                       if !sch.pool.Create(availableType) {
                                // Failed despite not being at quota,
                                // e.g., cloud ops throttled.
                                logger.Trace("pool declined to create new instance")
                                continue
                        }
-
-                       if dontstart[unallocType] {
-                               // We already tried & failed to start
-                               // a higher-priority container on the
-                               // same instance type. Don't let this
-                               // one sneak in ahead of it.
-                       } else if sch.pool.KillContainer(ctr.UUID, "about to start") {
-                               logger.Info("not restarting yet: crunch-run process from previous attempt has not exited")
-                       } else if sch.pool.StartContainer(unallocType, ctr) {
-                               logger.Trace("StartContainer => true")
-                       } else {
-                               logger.Trace("StartContainer => false")
-                               containerAllocatedWorkerBootingCount += 1
-                               dontstart[unallocType] = true
-                       }
+                       // Success. (Note pool.Create works
+                       // asynchronously and does its own logging
+                       // about the eventual outcome, so we don't
+                       // need to.)
+                       logger.Info("creating new instance")
+                       // Don't bother trying to start the container
+                       // yet -- obviously the instance will take
+                       // some time to boot and become ready.
+                       containerAllocatedWorkerBootingCount += 1
+                       dontstart[availableType] = true
                }
        }