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Merged
nickschuch merged 7 commits into from
Apr 14, 2026
Merged

feat: Application metrics and support undefined metrics #53

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3981787
Adding ability to detect application metrics
nterbogt Apr 7, 2026
4bbb97a
Adding a title to the definitions. Extending mock for application met…
nterbogt Apr 8, 2026
24a89fb
Fixing a linting issue
nterbogt Apr 8, 2026
2cf0734
Resolving issue with metric not having whether it's application or not.
nterbogt Apr 8, 2026
5ffe39d
Build metrics list once
nterbogt Apr 9, 2026
16b2b94
Moving application boolean to a source enum
nterbogt Apr 14, 2026
b12b007
More updates to source
nterbogt Apr 14, 2026
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102 changes: 59 additions & 43 deletions internal/server/mock/metrics/server.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,7 @@ import (
"context"
"fmt"
"hash/fnv"
"maps"
"slices"
"strings"
"time"

"github.com/skpr/api/pb"
Expand All @@ -19,6 +18,46 @@ type Server struct {
pb.UnimplementedMetricsServer
}

type MockMetric struct {
Min float64
Max float64
Source pb.MetricSource
}

// metricData is built once at package initialization
var metricData = map[pb.MetricType]map[string]MockMetric{
pb.MetricType_CLUSTER: {
"requests": {250_000, 4_000_000, pb.MetricSource_SYSTEM},
"httpcode_target_200": {500, 1_000, pb.MetricSource_SYSTEM},
"httpcode_target_300": {25, 50, pb.MetricSource_SYSTEM},
"httpcode_target_400": {10, 25, pb.MetricSource_SYSTEM},
"httpcode_target_500": {0, 10, pb.MetricSource_SYSTEM},
},
pb.MetricType_ENVIRONMENT: {
"requests": {25_000, 200_000, pb.MetricSource_SYSTEM},
"cpu": {25, 100, pb.MetricSource_SYSTEM},
"memory": {512_000, 4_294_967_296, pb.MetricSource_SYSTEM}, // 512KB to 4GB
"replicas": {2, 8, pb.MetricSource_SYSTEM},
"php_active": {4, 48, pb.MetricSource_SYSTEM},
"php_idle": {2, 12, pb.MetricSource_SYSTEM},
"php_queued": {0, 8, pb.MetricSource_SYSTEM},
"cache_hit_rate": {60, 99, pb.MetricSource_SYSTEM},
"invalidation_paths": {10, 50, pb.MetricSource_SYSTEM},
"invalidation_requests": {5, 20, pb.MetricSource_SYSTEM},
"origin_errors": {0, 10, pb.MetricSource_SYSTEM},
"httpcode_target_200": {200, 500, pb.MetricSource_SYSTEM},
"httpcode_target_300": {25, 50, pb.MetricSource_SYSTEM},
"httpcode_target_400": {10, 25, pb.MetricSource_SYSTEM},
"httpcode_target_500": {0, 10, pb.MetricSource_SYSTEM},
"response_times_avg": {0.1, 0.25, pb.MetricSource_SYSTEM},
"response_times_p95": {2.0, 5.0, pb.MetricSource_SYSTEM},
"response_times_p99": {10.0, 20.0, pb.MetricSource_SYSTEM},
"mock_application_1": {0, 100, pb.MetricSource_APPLICATION},
"mock_application_2": {0.3, 1.4, pb.MetricSource_APPLICATION},
"mock_application_3": {0, 100_000_000, pb.MetricSource_APPLICATION},
},
}

// deterministicRange returns a specific value consistently for a point in a time series.
func deterministicRange(t time.Time, minVal, maxVal float64, seconds int64, key string) float64 {
h := fnv.New32a()
Expand All @@ -31,54 +70,31 @@ func deterministicRange(t time.Time, minVal, maxVal float64, seconds int64, key
return minVal + (hashVal * rangeSize)
}

func metricMappings(metricType pb.MetricType) map[string][]float64 {
data := map[pb.MetricType]map[string][]float64{
pb.MetricType_CLUSTER: {
"requests": {250_000, 4_000_000},
"httpcode_target_200": {500, 1_000},
"httpcode_target_300": {25, 50},
"httpcode_target_400": {10, 25},
"httpcode_target_500": {0, 10},
},
pb.MetricType_ENVIRONMENT: {
"requests": {25_000, 200_000},
"cpu": {25, 100},
"memory": {512_000, 4_294_967_296}, // 512KB to 4GB
"replicas": {2, 8},
"php_active": {4, 48},
"php_idle": {2, 12},
"php_queued": {0, 8},
"cache_hit_rate": {60, 99},
"invalidation_paths": {10, 50},
"invalidation_requests": {5, 20},
"origin_errors": {0, 10},
"httpcode_target_200": {200, 500},
"httpcode_target_300": {25, 50},
"httpcode_target_400": {10, 25},
"httpcode_target_500": {0, 10},
"response_times_avg": {0.1, 0.25},
"response_times_p95": {2.0, 5.0},
"response_times_p99": {10.0, 20.0},
},
}
return data[metricType]
func metricMappings(metricType pb.MetricType) map[string]MockMetric {
return metricData[metricType]
}

// AvailableMetrics lists all available metrics.
func (s *Server) AvailableMetrics(ctx context.Context, req *pb.AvailableMetricsRequest) (*pb.AvailableMetricsResponse, error) {
mappings := metricMappings(req.Type)
keys := slices.Collect(maps.Keys(mappings))

metrics := make([]*pb.MetricDefinition, len(keys))
for i, key := range keys {
metrics[i] = &pb.MetricDefinition{
Name: key,
Type: req.Type,
availableMetrics := []*pb.MetricDefinition{}
for key, metric := range mappings {
// Hide application metrics for the prod environment.
if req.Environment != nil && *req.Environment == "prod" && metric.Source == pb.MetricSource_APPLICATION {
continue
}

availableMetrics = append(availableMetrics, &pb.MetricDefinition{
Name: key,
Type: req.Type,
Title: strings.ReplaceAll(key, "_", " "),
Source: metric.Source,
})
}

return &pb.AvailableMetricsResponse{
Metrics: metrics,
Metrics: availableMetrics,
}, nil
}

Expand All @@ -88,15 +104,15 @@ func (s *Server) AbsoluteRange(ctx context.Context, req *pb.AbsoluteRangeRequest
if _, ok := mappings[req.Metric]; !ok {
return nil, status.Errorf(codes.NotFound, "metric %s not found", req.Metric)
}
metricMin, metricMax := mappings[req.Metric][0], mappings[req.Metric][1]
metricMin, metricMax := mappings[req.Metric].Min, mappings[req.Metric].Max

output := []*pb.MetricValue{}
seedKey := fmt.Sprintf("%s_%s", req.Type, req.Metric)
metricTime := req.StartTime.AsTime()
for metricTime.Before(req.EndTime.AsTime()) {
cacheKey := fmt.Sprintf("%s_%s", req.Type, req.Metric)
metric := pb.MetricValue{
Timestamp: timestamppb.New(metricTime),
Value: deterministicRange(metricTime, metricMin, metricMax, 60, cacheKey),
Value: new(deterministicRange(metricTime, metricMin, metricMax, 60, seedKey)),
}
output = append(output, &metric)
metricTime = metricTime.Add(time.Minute)
Expand Down
16 changes: 13 additions & 3 deletions metrics.proto
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Original file line number Diff line number Diff line change
Expand Up @@ -14,20 +14,28 @@ service metrics {
rpc AbsoluteRange (AbsoluteRangeRequest) returns (AbsoluteRangeResponse) {}
}

// Top-level enum definition
// What the metric scope is.
enum MetricType {
METRIC_TYPE_UNSPECIFIED = 0;
CLUSTER = 1;
PROJECT = 2;
ENVIRONMENT = 3;
}

// Where this metric data is sourced.
enum MetricSource {
METRIC_SOURCE_UNSPECIFIED = 0;
SYSTEM = 1;
APPLICATION = 2;
}

/**
* Input for AvailableMetricsRequest.
*/
message AvailableMetricsRequest {
MetricType type = 1; // The type of the metric.
optional string environment = 2; // Name of the environment. Required when using ENVIRONMENT type.
optional MetricSource source = 3; // Whether to return only metrics with a specific source.
}

/**
Expand All @@ -43,6 +51,8 @@ message AvailableMetricsResponse {
message MetricDefinition {
string name = 1; // The name of the metric.
MetricType type = 2; // The type of the metric.
MetricSource source = 3; // The source of the metric data.
string title = 4; // A human-readable title for the metric.
}

/**
Expand All @@ -67,6 +77,6 @@ message AbsoluteRangeResponse {
* Output for a single metric response.
*/
message MetricValue {
google.protobuf.Timestamp timestamp = 1; // The timestamp of the metric..
double value = 2; // The value of the metric at the given timestamp.
google.protobuf.Timestamp timestamp = 1; // The timestamp of the metric.
optional double value = 2; // The value of the metric at the given timestamp.
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@nterbogt nterbogt Apr 13, 2026

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optional here is to support 0 being different from undefined. Nothing currently uses it, but I didn't want to do the 3 repo update again to change it later :)

}
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