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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/// This implements the developer facing API for labeled metrics.
///
/// Instances of this class type are automatically generated by the parsers at build time,
/// allowing developers to record values that were previously registered in the metrics.yaml file.
///
/// Unlike most metric types, LabeledMetricType does not have its own corresponding storage engine,
/// but records metrics for the underlying metric type `T` in the storage engine for that type.
/// The only difference is that labeled metrics are stored with the special key `$category.$name/$label`.
public class LabeledMetricType<T> {
let disabled: Bool
let sendInPings: [String]
let subMetric: T
let inner: AnyObject
/// The public constructor used by automatically generated metrics.
///
/// Supports the following types as sub-metrics:
/// * `BooleanMetricType`
/// * `CounterMetricType`
/// * `StringMetricType`
///
/// Throws an exception when used with unsupported sub-metrics.
public init(
category: String,
name: String,
sendInPings: [String],
lifetime: Lifetime,
disabled: Bool,
subMetric: T,
labels: [String]? = nil
) throws {
let meta = CommonMetricData(
category: category,
name: name,
sendInPings: sendInPings,
lifetime: lifetime,
disabled: disabled
)
self.disabled = disabled
self.sendInPings = sendInPings
self.subMetric = subMetric
switch subMetric {
case is CounterMetricType:
self.inner = LabeledCounter(.common(cmd: meta), labels)
case is BooleanMetricType:
self.inner = LabeledBoolean(.common(cmd: meta), labels)
case is StringMetricType:
self.inner = LabeledString(.common(cmd: meta), labels)
default:
throw "Can not create a labeled version of this metric type"
}
}
/// Get the specific metric for a given label.
///
/// If a set of acceptable labels was specified in the metrics.yaml file,
/// and the given label is not in the set, it will be recorded under the
/// special `OTHER_LABEL`.
///
/// If a set of acceptable labels was not specified in the metrics.yaml file,
/// only the first 16 unique labels will be used. After that, any additional
/// labels will be recorded under the special `OTHER_LABEL` label.
///
/// Labels must be snake_case and less than 30 characters. If an invalid label
/// is used, the metric will be recorded in the special `OTHER_LABEL` label.
///
/// - parameters:
/// * label: The label
/// - returns: The specific metric for that label
public subscript(label: String) -> T {
switch self.inner {
case is LabeledCounter:
return (self.inner as! LabeledCounter).get(label) as! T
case is LabeledBoolean:
return (self.inner as! LabeledBoolean).get(label) as! T
case is LabeledString:
return (self.inner as! LabeledString).get(label) as! T
default:
// The constructor will already throw an exception on an unhandled sub-metric type
assertUnreachable()
}
}
/// Returns the number of errors recorded for the given metric.
///
/// - parameters:
/// * errorType: The type of the error recorded.
/// - returns: the number of errors recorded for the metric.
public func testGetNumRecordedErrors(_ errorType: ErrorType) -> Int32 {
switch self.inner {
case is LabeledCounter:
return (self.inner as! LabeledCounter).testGetNumRecordedErrors(errorType)
case is LabeledBoolean:
return (self.inner as! LabeledBoolean).testGetNumRecordedErrors(errorType)
case is LabeledString:
return (self.inner as! LabeledString).testGetNumRecordedErrors(errorType)
default:
// The constructor will already throw an exception on an unhandled sub-metric type
assertUnreachable()
}
}
}