Documentation
¶
Overview ¶
Package database provides data persistence and retrieval.
Index ¶
- Variables
- type Database
- func (db *Database) Begin() error
- func (db *Database) Close() error
- func (db *Database) Commit() error
- func (db *Database) HostAdd(host *model.Host) error
- func (db *Database) HostDelete(host *model.Host) error
- func (db *Database) HostGetAll() ([]*model.Host, error)
- func (db *Database) HostGetByID(id int64) (*model.Host, error)
- func (db *Database) HostGetByName(name string) (*model.Host, error)
- func (db *Database) HostGetRecent(after time.Time) ([]*model.Host, error)
- func (db *Database) HostUpdateLastContact(host *model.Host, when time.Time) error
- func (db *Database) PerformMaintenance() error
- func (db *Database) RecordAdd(rec *model.Record) error
- func (db *Database) RecordAddBulk(name string, data []*model.Record) error
- func (db *Database) RecordGetByHost(host *model.Host, limit int64) ([]*model.Record, error)
- func (db *Database) RecordGetByHostPeriod(host *model.Host, begin, end time.Time) ([]*model.Record, error)
- func (db *Database) RecordGetByPeriod(begin, end time.Time) ([]*model.Record, error)
- func (db *Database) Rollback() error
- func (db *Database) SavepointCreate(name string) error
- func (db *Database) SavepointRelease(name string) error
- func (db *Database) SavepointRollback(name string) error
- type Pool
Constants ¶
This section is empty.
Variables ¶
var ErrEmptyUpdate = errors.New("update operation does not change any values")
ErrEmptyUpdate indicates that an update operation would not change any values.
var ErrInvalidSavepoint = errors.New("that save point does not exist")
ErrInvalidSavepoint is returned when a user of the Database uses an unkown (or expired) savepoint name.
var ErrInvalidValue = errors.New("invalid value for parameter")
ErrInvalidValue indicates that one or more parameters passed to a method had values that are invalid for that operation.
var ErrNoTxInProgress = errors.New("there is no transaction in progress")
ErrNoTxInProgress indicates that an attempt was made to finish a transaction when none was active.
var ErrObjectNotFound = errors.New("object was not found in database")
ErrObjectNotFound indicates that an Object was not found in the database.
var ErrTxInProgress = errors.New("a transaction is already in progress")
ErrTxInProgress indicates that an attempt to initiate a transaction failed because there is already one in progress.
Functions ¶
This section is empty.
Types ¶
type Database ¶
type Database struct {
// contains filtered or unexported fields
}
Database is the storage backend.
It is not safe to share a Database instance between goroutines, however opening multiple connections to the same Database is safe.
func Open ¶
Open opens a Database. If the database specified by the path does not exist, yet, it is created and initialized.
func (*Database) Begin ¶
Begin begins an explicit database transaction. Only one transaction can be in progress at once, attempting to start one, while another transaction is already in progress will yield ErrTxInProgress.
func (*Database) Close ¶
Close closes the database. If there is a pending transaction, it is rolled back.
func (*Database) Commit ¶
Commit ends the active transaction, making any changes made during that transaction permanent and visible to other connections. If no transaction is active, it returns ErrNoTxInProgress
func (*Database) HostDelete ¶
HostDelete deletes a Host from the Database.
func (*Database) HostGetAll ¶
HostGetAll fetches all Hosts that submitted data since the givem timestamp.
func (*Database) HostGetByID ¶
HostGetByID looks up a Host by its ID.
func (*Database) HostGetByName ¶
HostGetByName looks up a Host by its name.
func (*Database) HostGetRecent ¶
HostGetRecent fetches all Hosts that submitted data since the givem timestamp.
func (*Database) HostUpdateLastContact ¶
HostUpdateLastContact updates a Host's contact timestamp.
func (*Database) PerformMaintenance ¶
PerformMaintenance performs some maintenance operations on the database. It cannot be called while a transaction is in progress and will block pretty much all access to the database while it is running.
func (*Database) RecordAddBulk ¶
RecordAddBulk adds a sequence of Records from a single Host to the database in a single transaction.
func (*Database) RecordGetByHost ¶
RecordGetByHost loads up to <limit> Records from the given Host, ordered by their timestamps in descending order.
func (*Database) RecordGetByHostPeriod ¶
func (db *Database) RecordGetByHostPeriod(host *model.Host, begin, end time.Time) ([]*model.Record, error)
RecordGetByHostPeriod loads all Records from the given Host and timespan.
func (*Database) RecordGetByPeriod ¶
RecordGetByPeriod loads all Records from the given timespan in reverse chronological order
func (*Database) Rollback ¶
Rollback terminates a pending transaction, undoing any changes to the database made during that transaction. If no transaction is active, it returns ErrNoTxInProgress
func (*Database) SavepointCreate ¶
SavepointCreate creates a savepoint with the given name.
Savepoints only make sense within a running transaction, and just like with explicit transactions, managing them is the responsibility of the user of the Database.
Creating a savepoint without a surrounding transaction is not allowed, even though SQLite allows it.
For details on how Savepoints work, check the excellent SQLite documentation, but here's a quick guide:
Savepoints are kind-of-like transactions within a transaction: One can create a savepoint, make some changes to the database, and roll back to that savepoint, discarding all changes made between creating the savepoint and rolling back to it. Savepoints can be quite useful, but there are a few things to keep in mind:
Savepoints exist within a transaction. When the surrounding transaction is finished, all savepoints created within that transaction cease to exist, no matter if the transaction is commited or rolled back.
When the database is recovered after being interrupted during a transaction, e.g. by a power outage, the entire transaction is rolled back, including all savepoints that might exist.
When a savepoint is released, nothing changes in the state of the surrounding transaction. That means rolling back the surrounding transaction rolls back the entire transaction, regardless of any savepoints within.
Savepoints do not nest. Releasing a savepoint releases it and *all* existing savepoints that have been created before it. Rolling back to a savepoint removes that savepoint and all savepoints created after it.
func (*Database) SavepointRelease ¶
SavepointRelease releases the Savepoint with the given name, and all Savepoints created before the one being release.
func (*Database) SavepointRollback ¶
SavepointRollback rolls back the running transaction to the given savepoint.
type Pool ¶
type Pool struct {
// contains filtered or unexported fields
}
Pool is a pool of database connections
func NewPool ¶
NewPool creates a Pool of database connections. The number of connections to use is given by the parameter cnt.
func (*Pool) Close ¶
Close closes all open database connections currently in the pool and empties the pool. Any connections retrieved from the pool that are in use at the time Close is called are unaffected.
func (*Pool) Get ¶
Get returns a DB connection from the pool. If the pool is empty, it waits for a connection to be returned.
func (*Pool) GetNoWait ¶
GetNoWait returns a DB connection from the pool. If the pool is empty, it creates a new one.
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