Documentation
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Overview ¶
Package driver is the contract a database driver module implements to plug into pkg/db. It is a LEAF package: it imports nothing but the standard library, so a driver module can implement it without compiling the framework — the same reason pkg/storage/provider and pkg/auth/backend are leaves (ADR-025, ADR-026).
A driver module does two things in its init(), and both matter:
- it registers the database/sql driver, so sql.Open finds it;
- it registers how that driver reports a unique-constraint violation.
The second is the one that is easy to forget and expensive to omit. Without it, IsUniqueViolation does not fail — it answers false, and the branch that turns "that email is taken" into a 409 becomes dead code on that engine. A wrong answer is worse than a missing one, so a driver module that registers the driver without its classifier is a bug in the module, not a degraded mode of the framework.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
func MustRegisterUniqueViolation ¶
func MustRegisterUniqueViolation(engine string, fn UniqueViolationFunc)
MustRegisterUniqueViolation is RegisterUniqueViolation for use in an init(), where there is no caller to hand an error back to.
func RegisterUniqueViolation ¶
func RegisterUniqueViolation(engine string, fn UniqueViolationFunc) error
RegisterUniqueViolation records how the driver registered under engine — the database/sql driver name, e.g. "pgx", "mysql", "sqlite" — reports a unique-constraint violation.
It returns an error rather than panicking on a duplicate so that a module linked twice through different paths fails loudly at init in the module's own code, where the import that caused it is visible.
func RegisteredEngines ¶
func RegisteredEngines() []string
RegisteredEngines returns the engines that have a classifier, sorted. It is what an error message uses to tell an operator what IS linked in.
Types ¶
type UniqueViolationFunc ¶
UniqueViolationFunc reports whether err — as produced by one specific driver — was caused by a unique or primary-key constraint.
It must match on the CODE the driver reports, through errors.As, never on substrings of the message: PostgreSQL, MySQL, Oracle and SQL Server all translate their messages when the server runs in another language, so a substring check silently returns false on exactly the deployments where it matters. It must also walk the Unwrap chain, so a wrapped error still classifies.
It must return false for an error that did not come from its own driver: classifiers are consulted in turn, and one that claims errors it does not recognise would answer for another engine.
func UniqueViolationFuncs ¶
func UniqueViolationFuncs() []UniqueViolationFunc
UniqueViolationFuncs returns the registered classifiers, in a stable order so that classification does not depend on map iteration.
Source Files
Directories
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Package drivertest is a conformance kit for database driver modules.
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Package drivertest is a conformance kit for database driver modules. |