feat(applicationsignals-alpha): introduce Application Signals SLO L2 constructs

packages/@aws-cdk/aws-applicationsignals-alpha/README.md

@@ -287,3 +287,91 @@ class MyStack extends cdk.Stack {
   }
 }
 ```
+
+## Application Signals SLO L2 Constructs
+
+A collection of L2 constructs which leverages native L1 CFN resources, simplifying Application Signals Service Level 
+Objectives (SLOs) creation process to monitor the reliability of a service against customer expectations.
+
+
+### ServiceLevelObjective
+
+`ServiceLevelObjective` aims to address key challenges in the current CDK process of creating and managing SLOs while providing the flexibility.
+The construct provides two types of SLOs:<br>
+Period-based SLOs: Evaluate performance against goals using defined time periods.<br>
+Request-based SLOs: Measure performance based on request success ratios
+
+Key Features:
+
+1. Easy creation of both period-based and request-based SLOs.
+2. Support for custom CloudWatch metrics and math expressions.
+3. Automatic error budget calculation and tracking.
+
+#### Use Case 1 - Create a Period-based SLO with custom metrics, default attainmentGoal: 99.9 and warningThreshold: 30
+
+```
+const periodSlo = ServiceLevelObjective.periodBased(this, 'PeriodSLO', {
+  name: 'my-period-slo',
+  goal: {
+    interval: Interval.rolling({
+      duration: 7,
+      unit: DurationUnit.DAY,
+    }),
+  },
+  metric: {
+    metricThreshold: 100,
+    periodSeconds: 300,
+    statistic: 'Average',
+    metricDataQueries: [/* ... */],
+  },
+});
+```
+
+#### Use Case 2 - Create a Period-based SLO with service/operation, attainmentGoal is 99.99 and warningThreshold is 50
+
+```
+const availabilitySlo = ServiceLevelObjective.periodBased(this, 'ApiAvailabilitySlo', {
+  name: 'api-availability-slo',
+  description: 'API endpoint availability SLO',
+  goal: {
+    attainmentGoal: 99.99,
+    warningThreshold: 50,
+    interval: Interval.calendar({
+      duration: 1,
+      unit: DurationUnit.MONTH,
+      // default startTime is now,
+    }),
+  },
+  metric: {
+    metricThreshold: 99,
+    metricType: MetricType.AVAILABILITY,
+    operationName: 'OrderProcessing',
+    keyAttributes: KeyAttributes.service({
+     name: 'MyService',
+     environment: 'Development',
+   });
+    periodSeconds: 300,
+    statistic: 'Average',
+  },
+});
+```
+
+#### Use Case 3 - Create request based SLO with custom metrics
+
+```
+const requestSlo = ServiceLevelObjective.requestBased(this, 'RequestSLO', {
+  name: 'my-request-slo',
+  goal: {
+    interval: Interval.calendar({
+      duration: 30,
+      unit: DurationUnit.DAY,
+      startTime: 1,
+    }),
+  },
+  metric: {
+    metricThreshold: 200,
+    goodCountMetrics: [/* ... */],
+    totalCountMetrics: [/* ... */],
+  },
+});
+```

packages/@aws-cdk/aws-applicationsignals-alpha/lib/index.ts

@@ -4,3 +4,5 @@ export * from './enablement/constants';
 export * from './enablement/instrumentation-versions';
 export * from './enablement/ecs-cloudwatch-agent';
 export * from './enablement/ecs-sdk-instrumentation';
+export * from './slo/slo';
+export * from './slo/slo-types';

packages/@aws-cdk/aws-applicationsignals-alpha/lib/slo/constants.ts

@@ -0,0 +1,162 @@
+/**
+ * Types of metrics that can be used for SLIs
+ */
+export enum MetricType {
+    /**
+     * Latency-based metric type
+     * Used for measuring response time or duration
+     */
+    LATENCY = 'LATENCY',
+
+    /**
+     * Availability-based metric type
+     * Used for measuring uptime or success rate
+     */
+    AVAILABILITY = 'AVAILABILITY'
+}
+
+/**
+ * Default values for goal configuration
+ */
+export const DEFAULT_GOAL_CONFIG = {
+    ATTAINMENT_GOAL: 99.9,
+    WARNING_THRESHOLD: 30,
+} as const;
+
+/**
+ * Comparison operators for metric thresholds
+ */
+export enum ComparisonOperator {
+    /**
+     * Greater than operator
+     * True if metric value is strictly greater than threshold
+     */
+    GREATER_THAN = 'GREATER_THAN',
+
+    /**
+     * Less than operator
+     * True if metric value is strictly less than threshold
+     */
+    LESS_THAN = 'LESS_THAN',
+
+    /**
+     * Greater than or equal operator
+     * True if metric value is greater than or equal to threshold
+     */
+    GREATER_THAN_OR_EQUAL = 'GREATER_THAN_OR_EQUAL',
+
+    /**
+     * Less than or equal operator
+     * True if metric value is less than or equal to threshold
+     */
+    LESS_THAN_OR_EQUAL = 'LESS_THAN_OR_EQUAL'
+}
+
+/**
+ * Statistical methods for aggregating metric values
+ */
+export enum MetricStatistic {
+    /**
+     * Average of all values in the period
+     */
+    AVERAGE = 'Average',
+
+    /**
+     * Sum of all values in the period
+     */
+    SUM = 'Sum',
+
+    /**
+     * Minimum value in the period
+     */
+    MINIMUM = 'Minimum',
+
+    /**
+     * Maximum value in the period
+     */
+    MAXIMUM = 'Maximum',
+
+    /**
+     * Count of samples in the period
+     */
+    SAMPLE_COUNT = 'SampleCount',
+
+    /**
+     * 99th percentile of values in the period
+     */
+    P99 = 'p99',
+
+    /**
+     * 95th percentile of values in the period
+     */
+    P95 = 'p95',
+
+    /**
+     * 90th percentile of values in the period
+     */
+    P90 = 'p90',
+
+    /**
+     * 50th percentile (median) of values in the period
+     */
+    P50 = 'p50'
+}
+
+/**
+ * Types of services that can be monitored
+ */
+export enum KeyAttributeType {
+    /**
+     * Service running in your account
+     */
+    SERVICE = 'SERVICE',
+
+    /**
+     * AWS managed service
+     */
+    AWS_SERVICE = 'AWS_SERVICE',
+
+    /**
+     * External service
+     */
+    REMOTE_SERVICE = 'REMOTE_SERVICE',
+
+    /**
+     * Resource
+     */
+
+    RESOURCE = 'RESOURCE',
+
+    /**
+     * AWS managed Resource
+     */
+
+    AWS_RESOURCE = 'AWS::RESOURCE'
+
+}
+
+/**
+ * Units for duration measurement in SLO intervals
+ */
+export enum DurationUnit {
+    /**
+     * Minute unit for fine-grained intervals
+     */
+    MINUTE = 'MINUTE',
+
+    /**
+     * Hour unit for medium-term intervals
+     */
+    HOUR = 'HOUR',
+
+    /**
+     * Day unit for daily intervals
+     */
+    DAY = 'DAY',
+
+    /**
+     * Month unit for long-term intervals
+     * Used for calendar-aligned monitoring
+     */
+    MONTH = 'MONTH'
+}