forked from vmware-archive/atc
/
resource_cache.go
236 lines (202 loc) · 5.44 KB
/
resource_cache.go
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package db
import (
"crypto/sha256"
"database/sql"
"encoding/json"
"errors"
"fmt"
"code.cloudfoundry.org/lager"
sq "github.com/Masterminds/squirrel"
"github.com/concourse/atc"
"github.com/lib/pq"
)
var ErrResourceCacheAlreadyExists = errors.New("resource-cache-already-exists")
var ErrResourceCacheDisappeared = errors.New("resource-cache-disappeared")
// ResourceCache represents an instance of a ResourceConfig's version.
//
// A ResourceCache is created by a `get`, an `image_resource`, or a resource
// type in a pipeline.
//
// ResourceCaches are garbage-collected by gc.ResourceCacheCollector.
type ResourceCache struct {
ResourceConfig ResourceConfig // The resource configuration.
Version atc.Version // The version of the resource.
Params atc.Params // The params used when fetching the version.
}
// UsedResourceCache is created whenever a ResourceCache is Created and/or
// Used.
//
// So long as the UsedResourceCache exists, the underlying ResourceCache can
// not be removed.
//
// UsedResourceCaches become unused by the gc.ResourceCacheCollector, which may
// then lead to the ResourceCache being garbage-collected.
//
// See FindOrCreateForBuild, FindOrCreateForResource, and
// FindOrCreateForResourceType for more information on when it becomes unused.
type UsedResourceCache struct {
ID int
ResourceConfig *UsedResourceConfig
Version atc.Version
}
func (cache *UsedResourceCache) Destroy(tx Tx) (bool, error) {
rows, err := psql.Delete("resource_caches").
Where(sq.Eq{
"id": cache.ID,
}).
RunWith(tx).
Exec()
if err != nil {
return false, err
}
affected, err := rows.RowsAffected()
if err != nil {
return false, err
}
if affected == 0 {
return false, ErrResourceCacheDisappeared
}
return true, nil
}
func (cache ResourceCache) Find(tx Tx) (*UsedResourceCache, bool, error) {
usedResourceConfig, found, err := cache.ResourceConfig.Find(tx)
if err != nil {
return nil, false, err
}
if !found {
return nil, false, nil
}
return cache.findWithResourceConfig(tx, usedResourceConfig)
}
func (cache ResourceCache) findOrCreate(
logger lager.Logger,
tx Tx,
user ResourceUser,
forColumnName string,
forColumnID int,
) (*UsedResourceCache, error) {
usedResourceConfig, err := user.UseResourceConfig(logger, tx, cache.ResourceConfig)
if err != nil {
return nil, err
}
rc, found, err := cache.findWithResourceConfig(tx, usedResourceConfig)
if err != nil {
return nil, err
}
if !found {
var id int
err = psql.Insert("resource_caches").
Columns(
"resource_config_id",
"version",
"params_hash",
).
Values(
usedResourceConfig.ID,
cache.version(),
paramsHash(cache.Params),
).
Suffix("RETURNING id").
RunWith(tx).
QueryRow().
Scan(&id)
if err != nil {
if pqErr, ok := err.(*pq.Error); ok && pqErr.Code.Name() == "foreign_key_violation" {
return nil, ErrSafeRetryFindOrCreate
}
if pqErr, ok := err.(*pq.Error); ok && pqErr.Code.Name() == "unique_violation" {
return nil, ErrSafeRetryFindOrCreate
}
return nil, err
}
rc = &UsedResourceCache{
ID: id,
ResourceConfig: usedResourceConfig,
Version: cache.Version,
}
}
var resourceCacheUseExists int
err = psql.Select("1").
From("resource_cache_uses").
Where(sq.Eq{
"resource_cache_id": rc.ID,
forColumnName: forColumnID,
}).
RunWith(tx).
QueryRow().
Scan(&resourceCacheUseExists)
if err != nil {
if err == sql.ErrNoRows {
_, err = psql.Insert("resource_cache_uses").
Columns(
"resource_cache_id",
forColumnName,
).
Values(
rc.ID,
forColumnID,
).
RunWith(tx).
Exec()
if err != nil {
if pqErr, ok := err.(*pq.Error); ok && pqErr.Code.Name() == "foreign_key_violation" {
if pqErr.Constraint == "resource_cache_uses_resource_cache_id_fkey" {
return nil, ErrSafeRetryFindOrCreate
} else {
return nil, UserDisappearedError{user}
}
}
return nil, err
}
return rc, nil
}
return nil, err
}
return rc, nil
}
func (cache ResourceCache) lockName() (string, error) {
cacheJSON, err := json.Marshal(cache)
if err != nil {
return "", err
}
return fmt.Sprintf("%x", sha256.Sum256(cacheJSON)), nil
}
func (cache ResourceCache) findWithResourceConfig(tx Tx, resourceConfig *UsedResourceConfig) (*UsedResourceCache, bool, error) {
var id int
err := psql.Select("id").From("resource_caches").Where(sq.Eq{
"resource_config_id": resourceConfig.ID,
"version": cache.version(),
"params_hash": paramsHash(cache.Params),
}).RunWith(tx).QueryRow().Scan(&id)
if err != nil {
if err == sql.ErrNoRows {
return nil, false, nil
}
return nil, false, err
}
return &UsedResourceCache{
ID: id,
ResourceConfig: resourceConfig,
Version: cache.Version,
}, true, nil
}
func (cache ResourceCache) version() string {
j, _ := json.Marshal(cache.Version)
return string(j)
}
func (usedResourceCache *UsedResourceCache) BaseResourceType() *UsedBaseResourceType {
if usedResourceCache.ResourceConfig.CreatedByBaseResourceType != nil {
return usedResourceCache.ResourceConfig.CreatedByBaseResourceType
}
return usedResourceCache.ResourceConfig.CreatedByResourceCache.BaseResourceType()
}
func paramsHash(p atc.Params) string {
if p != nil {
return mapHash(p)
}
return mapHash(atc.Params{})
}
func mapHash(m map[string]interface{}) string {
j, _ := json.Marshal(m)
return fmt.Sprintf("%x", sha256.Sum256(j))
}