Merge cdda011 into ac1f8ea

Source/common/BUILD

@@ -188,6 +188,12 @@ objc_library(
     ],
 )
 
+objc_library(
+    name = "SNTMetricSet",
+    srcs = ["SNTMetricSet.m"],
+    hdrs = ["SNTMetricSet.h"],
+)
+
 objc_library(
     name = "SNTXPCSyncdInterface",
     srcs = ["SNTXPCSyncdInterface.m"],
@@ -241,5 +247,11 @@ santa_unit_test(
 santa_unit_test(
     name = "SNTPrefixTreeTest",
     srcs = ["SNTPrefixTreeTest.mm"],
-    deps = ["SNTPrefixTree"],
+    deps = [":SNTPrefixTree"],
+)
+
+santa_unit_test(
+    name = "SNTMetricSetTest",
+    srcs = ["SNTMetricSetTest.m"],
+    deps = [":SNTMetricSet"],
 )

Source/common/SNTMetricSet.h

@@ -0,0 +1,173 @@
+/// Copyright 2021 Google Inc. All rights reserved.
+///
+/// Licensed under the Apache License, Version 2.0 (the "License");
+/// you may not use this file except in compliance with the License.
+/// You may obtain a copy of the License at
+///
+///    http://www.apache.org/licenses/LICENSE-2.0
+///
+///    Unless required by applicable law or agreed to in writing, software
+///    distributed under the License is distributed on an "AS IS" BASIS,
+///    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+///    See the License for the specific language governing permissions and
+///    limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+/**
+ * Provides an abstraction for various metric systems that will be exported to
+ * monitoring systems via the MetricService. This is used to store internal
+ * counters and metrics that can be exported to an external monitoring system.
+ *
+ * `SNTMetricSet` for storing and creating metrics and counters. This is
+ *   the externally visible interface
+ *   class.
+ *
+ *  Metric classes:
+ *   * `SNTMetric` to store metric values broken down by "field" dimensions.
+ *   * subclasses of `SNTMetric` with suitable setters:
+ *     * `SNTMetricCounter`
+ *     * `SNTMetricGaugeInt64`
+ *     * `SNTMetricGaugeDouble`
+ *     * `SNTMetricString`
+ *     * `SNTMetricBool`
+ */
+
+NS_ASSUME_NONNULL_BEGIN
+
+typedef NS_ENUM(NSInteger, SNTMetricType) {
+  SNTMetricTypeUnknown = 0,
+  SNTMetricTypeConstantBool = 1,
+  SNTMetricTypeConstantString = 2,
+  SNTMetricTypeConstantInt64 = 3,
+  SNTMetricTypeConstantDouble = 4,
+  SNTMetricTypeGaugeBool = 5,
+  SNTMetricTypeGaugeString = 6,
+  SNTMetricTypeGaugeInt64 = 7,
+  SNTMetricTypeGaugeDouble = 8,
+  SNTMetricTypeCounter = 9,
+};
+
+@interface SNTMetric : NSObject
+- (NSDictionary *)export;
+@end
+
+@interface SNTMetricCounter : SNTMetric
+- (void)incrementBy:(long long)step forFieldValues:(NSArray<NSString *> *)fieldValues;
+- (void)incrementForFieldValues:(NSArray<NSString *> *)fieldValues;
+- (long long)getCountForFieldValues:(NSArray<NSString *> *)fieldValues;
+@end
+
+@interface SNTMetricInt64Gauge : SNTMetric
+- (void)set:(long long)value forFieldValues:(NSArray<NSString *> *)fieldValues;
+- (long long)getGaugeValueForFieldValues:(NSArray<NSString *> *)fieldValues;
+@end
+
+@interface SNTMetricDoubleGauge : SNTMetric
+- (void)set:(double)value forFieldValues:(NSArray<NSString *> *)fieldValues;
+- (double)getGaugeValueForFieldValues:(NSArray<NSString *> *)fieldValues;
+@end
+
+@interface SNTMetricStringGauge : SNTMetric
+- (void)set:(NSString *)value forFieldValues:(NSArray<NSString *> *)fieldValues;
+- (NSString *)getStringValueForFieldValues:(NSArray<NSString *> *)fieldValues;
+@end
+
+@interface SNTMetricBooleanGauge : SNTMetric
+- (void)set:(BOOL)value forFieldValues:(NSArray<NSString *> *)fieldValues;
+- (BOOL)getBoolValueForFieldValues:(NSArray<NSString *> *)fieldValues;
+@end
+
+/**
+ * A registry of metrics with associated fields.
+ */
+@interface SNTMetricSet : NSObject
+- (instancetype)initWithHostname:(NSString *)hostname username:(NSString *)username;
+
+/* Returns a counter with the given name, field names and help
+ *  text, registered with the MetricSet.
+ *
+ * @param name The counter name, for example @"/proc/cpu".
+ * @param fieldNames The counter's field names, for example @[@"result"].
+ * @param helpText The counter's help description.
+ * @return A counter with the given specification registered with this root.
+ *   The returned counter might have been created earlier with the same
+ *   specification.
+ * @throw NSInternalInconsistencyException When trying to register a second
+ *   counter with the same name but a different schema as an existing one
+ */
+- (SNTMetricCounter *)counterWithName:(NSString *)name
+                           fieldNames:(NSArray<NSString *> *)fieldNames
+                             helpText:(NSString *)text;
+
+- (void)addRootLabel:(NSString *)label value:(NSString *)value;
+
+/**
+ * Returns a int64 gauge metric with the given Streamz name and help text,
+ * registered with this MetricSet.
+ *
+ * @param name The metric name, for example @"/memory/free".
+ * @param fieldNames The metric's field names, for example @[@"type"].
+ * @param helpText The metric's help description.
+ */
+- (SNTMetricInt64Gauge *)int64GaugeWithName:(NSString *)name
+                                 fieldNames:(NSArray<NSString *> *)fieldNames
+                                   helpText:(NSString *)helpText;
+
+/**
+ * Returns a double gauge metric with the given name and help text,
+ * registered with this root.
+ *
+ * @param name The metric name, for example @"/memory/free".
+ * @param fieldNames The metric's field names, for example @[@"type"].
+ * @param helpText The metric's help description.
+ */
+- (SNTMetricDoubleGauge *)doubleGaugeWithName:(NSString *)name
+                                   fieldNames:(NSArray<NSString *> *)fieldNames
+                                     helpText:(NSString *)helpText;
+
+/**
+ * Returns a string gauge metric with the given name and help text,
+ * registered with this metric set.
+ *
+ * @param name The metric name, for example @"/santa/mode".
+ * @param fieldNames The metric's field names, for example @[@"type"].
+ * @param helpText The metric's help description.
+ */
+- (SNTMetricStringGauge *)stringGaugeWithName:(NSString *)name
+                                   fieldNames:(NSArray<NSString *> *)fieldNames
+                                     helpText:(NSString *)helpText;
+
+/**
+ * Returns a boolean gauge metric with the given name and help text,
+ * registered with this metric set.
+ *
+ * @param name The metric name, for example @"/memory/free".
+ * @param fieldNames The metric's field names, for example @[@"type"].
+ * @param helpText The metric's help description.
+ */
+- (SNTMetricBooleanGauge *)booleanGaugeWithName:(NSString *)name
+                                     fieldNames:(NSArray<NSString *> *)fieldNames
+                                       helpText:(NSString *)helpText;
+
+/** Creates a constant metric with a string value and no fields. */
+- (void)addConstantStringWithName:(NSString *)name
+                         helpText:(NSString *)helpText
+                            value:(NSString *)value;
+
+/** Creates a constant metric with an integer value and no fields. */
+- (void)addConstantIntegerWithName:(NSString *)name
+                          helpText:(NSString *)helpText
+                             value:(long long)value;
+
+/** Creates a constant metric with an integer value and no fields. */
+- (void)addConstantBooleanWithName:(NSString *)name helpText:(NSString *)helpText value:(BOOL)value;
+
+/** Register a callback to get executed just before each export. */
+- (void)registerCallback:(void (^)(void))callback;
+
+/** Export creates an NSDictionary of the state of the metrics */
+- (NSDictionary *)export;
+@end
+
+NS_ASSUME_NONNULL_END