Updated the Probe method in the Persistence package with a query deadline.

This commit is contained in:
2026-08-13 00:11:59 +02:00
parent 8303598244
commit d7465d03cc
4 changed files with 138 additions and 15 deletions
@@ -12,14 +12,21 @@ public struct Probe: Sendable {
/// The `Fluent` service whose default database is probed.
private let fluent: Fluent
/// The longest the probe waits for the database's answer before reporting it as not reachable.
private let timeout: Duration
// MARK: Initializers
/// Creates a probe for the default database of the given `Fluent` service.
/// - Parameter fluent: the `Fluent` service whose default database is probed.
/// - Parameters:
/// - fluent: the `Fluent` service whose default database is probed.
/// - timeout: the longest the probe waits for the database's answer before reporting it as not reachable.
public init(
fluent: Fluent
fluent: Fluent,
timeout: Duration = .seconds(2)
) {
self.fluent = fluent
self.timeout = timeout
}
// MARK: Methods
@@ -28,21 +35,43 @@ public struct Probe: Sendable {
///
/// Runs a trivial `SELECT 1` against the default database the cheapest statement both the PostgreSQL and SQLite backends understand so
/// a readiness check does not depend on any particular schema or model. Any failure (connection refused, authentication error, pool exhausted) is
/// reported as not reachable rather than thrown, so callers can map it straight onto a readiness response. A default database that is not an SQL
/// database is likewise reported as not reachable.
/// - Returns: `true` when the database answers the probe, `false` otherwise.
/// reported as not reachable rather than thrown, and an answer that does not arrive within the timeout is likewise reported as not reachable so
/// a database that hangs yields a prompt "not ready" instead of a hanging readiness endpoint. A default database that is not an SQL database is
/// also reported as not reachable.
/// - Returns: `true` when the database answers the probe in time, `false` otherwise.
public func callAsFunction() async -> Bool {
guard let database = fluent.db() as? any SQLDatabase else {
return false
}
do {
try await database.raw("SELECT 1").run()
return true
} catch {
return false
// The query is raced against the deadline from unstructured tasks whose first answer wins: a structured group
// would await the query child before returning, so a database that hangs mid-query the very failure the
// deadline exists for would hang the probe with it. The loser is cancelled and abandoned; a late answer lands
// in a finished stream and is dropped.
let (answers, continuation) = AsyncStream.makeStream(of: Bool.self)
let query = Task {
do {
try await database
.raw("SELECT 1")
.run()
continuation.yield(true)
} catch {
continuation.yield(false)
}
}
let deadline = Task {
try? await Task.sleep(for: timeout)
continuation.yield(false)
}
var answer = answers.makeAsyncIterator()
let isReachable = await answer.next() ?? false
query.cancel()
deadline.cancel()
return isReachable
}
}