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DrydockBlueprintImplementation.php
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Mon, Apr 28, 11:23

DrydockBlueprintImplementation.php
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<?php
/**
* @task lease Lease Acquisition
* @task resource Resource Allocation
* @task interface Resource Interfaces
* @task log Logging
*/
abstract class DrydockBlueprintImplementation extends Phobject {
abstract public function getType();
abstract public function isEnabled();
abstract public function getBlueprintName();
abstract public function getDescription();
public function getFieldSpecifications() {
return array();
}
/* -( Lease Acquisition )-------------------------------------------------- */
/**
* Enforce basic checks on lease/resource compatibility. Allows resources to
* reject leases if they are incompatible, even if the resource types match.
*
* For example, if a resource represents a 32-bit host, this method might
* reject leases that need a 64-bit host. The blueprint might also reject
* a resource if the lease needs 8GB of RAM and the resource only has 6GB
* free.
*
* This method should not acquire locks or expect anything to be locked. This
* is a coarse compatibility check between a lease and a resource.
*
* @param DrydockBlueprint Concrete blueprint to allocate for.
* @param DrydockResource Candidiate resource to allocate the lease on.
* @param DrydockLease Pending lease that wants to allocate here.
* @return bool True if the resource and lease are compatible.
* @task lease
*/
abstract public function canAcquireLeaseOnResource(
DrydockBlueprint $blueprint,
DrydockResource $resource,
DrydockLease $lease);
/**
* Acquire a lease. Allows resources to peform setup as leases are brought
* online.
*
* If acquisition fails, throw an exception.
*
* @param DrydockBlueprint Blueprint which built the resource.
* @param DrydockResource Resource to acquire a lease on.
* @param DrydockLease Requested lease.
* @return void
* @task lease
*/
abstract public function acquireLease(
DrydockBlueprint $blueprint,
DrydockResource $resource,
DrydockLease $lease);
/**
* @return void
* @task lease
*/
public function activateLease(
DrydockBlueprint $blueprint,
DrydockResource $resource,
DrydockLease $lease) {
throw new PhutilMethodNotImplementedException();
}
/**
* React to a lease being released.
*
* This callback is primarily useful for automatically releasing resources
* once all leases are released.
*
* @param DrydockBlueprint Blueprint which built the resource.
* @param DrydockResource Resource a lease was released on.
* @param DrydockLease Recently released lease.
* @return void
* @task lease
*/
abstract public function didReleaseLease(
DrydockBlueprint $blueprint,
DrydockResource $resource,
DrydockLease $lease);
/**
* Destroy any temporary data associated with a lease.
*
* If a lease creates temporary state while held, destroy it here.
*
* @param DrydockBlueprint Blueprint which built the resource.
* @param DrydockResource Resource the lease is acquired on.
* @param DrydockLease The lease being destroyed.
* @return void
* @task lease
*/
abstract public function destroyLease(
DrydockBlueprint $blueprint,
DrydockResource $resource,
DrydockLease $lease);
/* -( Resource Allocation )------------------------------------------------ */
/**
* Enforce fundamental implementation/lease checks. Allows implementations to
* reject a lease which no concrete blueprint can ever satisfy.
*
* For example, if a lease only builds ARM hosts and the lease needs a
* PowerPC host, it may be rejected here.
*
* This is the earliest rejection phase, and followed by
* @{method:canEverAllocateResourceForLease}.
*
* This method should not actually check if a resource can be allocated
* right now, or even if a blueprint which can allocate a suitable resource
* really exists, only if some blueprint may conceivably exist which could
* plausibly be able to build a suitable resource.
*
* @param DrydockLease Requested lease.
* @return bool True if some concrete blueprint of this implementation's
* type might ever be able to build a resource for the lease.
* @task resource
*/
abstract public function canAnyBlueprintEverAllocateResourceForLease(
DrydockLease $lease);
/**
* Enforce basic blueprint/lease checks. Allows blueprints to reject a lease
* which they can not build a resource for.
*
* This is the second rejection phase. It follows
* @{method:canAnyBlueprintEverAllocateResourceForLease} and is followed by
* @{method:canAllocateResourceForLease}.
*
* This method should not check if a resource can be built right now, only
* if the blueprint as configured may, at some time, be able to build a
* suitable resource.
*
* @param DrydockBlueprint Blueprint which may be asked to allocate a
* resource.
* @param DrydockLease Requested lease.
* @return bool True if this blueprint can eventually build a suitable
* resource for the lease, as currently configured.
* @task resource
*/
abstract public function canEverAllocateResourceForLease(
DrydockBlueprint $blueprint,
DrydockLease $lease);
/**
* Enforce basic availability limits. Allows blueprints to reject resource
* allocation if they are currently overallocated.
*
* This method should perform basic capacity/limit checks. For example, if
* it has a limit of 6 resources and currently has 6 resources allocated,
* it might reject new leases.
*
* This method should not acquire locks or expect locks to be acquired. This
* is a coarse check to determine if the operation is likely to succeed
* right now without needing to acquire locks.
*
* It is expected that this method will sometimes return `true` (indicating
* that a resource can be allocated) but find that another allocator has
* eaten up free capacity by the time it actually tries to build a resource.
* This is normal and the allocator will recover from it.
*
* @param DrydockBlueprint The blueprint which may be asked to allocate a
* resource.
* @param DrydockLease Requested lease.
* @return bool True if this blueprint appears likely to be able to allocate
* a suitable resource.
* @task resource
*/
abstract public function canAllocateResourceForLease(
DrydockBlueprint $blueprint,
DrydockLease $lease);
/**
* Allocate a suitable resource for a lease.
*
* This method MUST acquire, hold, and manage locks to prevent multiple
* allocations from racing. World state is not locked before this method is
* called. Blueprints are entirely responsible for any lock handling they
* need to perform.
*
* @param DrydockBlueprint The blueprint which should allocate a resource.
* @param DrydockLease Requested lease.
* @return DrydockResource Allocated resource.
* @task resource
*/
abstract public function allocateResource(
DrydockBlueprint $blueprint,
DrydockLease $lease);
/**
* @task resource
*/
public function activateResource(
DrydockBlueprint $blueprint,
DrydockResource $resource) {
throw new PhutilMethodNotImplementedException();
}
/**
* Destroy any temporary data associated with a resource.
*
* If a resource creates temporary state when allocated, destroy that state
* here. For example, you might shut down a virtual host or destroy a working
* copy on disk.
*
* @param DrydockBlueprint Blueprint which built the resource.
* @param DrydockResource Resource being destroyed.
* @return void
* @task resource
*/
abstract public function destroyResource(
DrydockBlueprint $blueprint,
DrydockResource $resource);
/* -( Resource Interfaces )------------------------------------------------ */
abstract public function getInterface(
DrydockBlueprint $blueprint,
DrydockResource $resource,
DrydockLease $lease,
$type);
/* -( Logging )------------------------------------------------------------ */
public static function getAllBlueprintImplementations() {
return id(new PhutilClassMapQuery())
->setAncestorClass(__CLASS__)
->execute();
}
public static function getNamedImplementation($class) {
return idx(self::getAllBlueprintImplementations(), $class);
}
protected function newResourceTemplate(
DrydockBlueprint $blueprint,
$name) {
$resource = id(new DrydockResource())
->setBlueprintPHID($blueprint->getPHID())
->attachBlueprint($blueprint)
->setType($this->getType())
->setStatus(DrydockResourceStatus::STATUS_PENDING)
->setName($name);
// Pre-allocate the resource PHID.
$resource->setPHID($resource->generatePHID());
return $resource;
}
protected function newLease(DrydockBlueprint $blueprint) {
return id(new DrydockLease());
}
protected function requireActiveLease(DrydockLease $lease) {
$lease_status = $lease->getStatus();
switch ($lease_status) {
case DrydockLeaseStatus::STATUS_ACQUIRED:
// TODO: Temporary failure.
throw new Exception(pht('Lease still activating.'));
case DrydockLeaseStatus::STATUS_ACTIVE:
return;
default:
// TODO: Permanent failure.
throw new Exception(pht('Lease in bad state.'));
}
}
}

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