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internal/config/config.go

@@ -0,0 +1,112 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+)
+
+// For aggregation over multiple values at different cpus/sockets/..., not time!
+type AggregationStrategy int
+
+const (
+	NoAggregation AggregationStrategy = iota
+	SumAggregation
+	AvgAggregation
+)
+
+func (as *AggregationStrategy) UnmarshalJSON(data []byte) error {
+	var str string
+	if err := json.Unmarshal(data, &str); err != nil {
+		return err
+	}
+
+	switch str {
+	case "":
+		*as = NoAggregation
+	case "sum":
+		*as = SumAggregation
+	case "avg":
+		*as = AvgAggregation
+	default:
+		return fmt.Errorf("invalid aggregation strategy: %#v", str)
+	}
+	return nil
+}
+
+type MetricConfig struct {
+	// Interval in seconds at which measurements will arive.
+	Frequency int64 `json:"frequency"`
+
+	// Can be 'sum', 'avg' or null. Describes how to aggregate metrics from the same timestep over the hierarchy.
+	Aggregation AggregationStrategy `json:"aggregation"`
+
+	// Private, used internally...
+	offset int
+}
+
+type HttpConfig struct {
+	// Address to bind to, for example "0.0.0.0:8081"
+	Address string `json:"address"`
+
+	// If not the empty string, use https with this as the certificate file
+	CertFile string `json:"https-cert-file"`
+
+	// If not the empty string, use https with this as the key file
+	KeyFile string `json:"https-key-file"`
+}
+
+type NatsConfig struct {
+	// Address of the nats server
+	Address string `json:"address"`
+
+	// Username/Password, optional
+	Username string `json:"username"`
+	Password string `json:"password"`
+
+	Subscriptions []struct {
+		// Channel name
+		SubscribeTo string `json:"subscribe-to"`
+
+		// Allow lines without a cluster tag, use this as default, optional
+		ClusterTag string `json:"cluster-tag"`
+	} `json:"subscriptions"`
+}
+
+type Config struct {
+	Metrics     map[string]MetricConfig `json:"metrics"`
+	HttpConfig  *HttpConfig             `json:"http-api"`
+	Checkpoints struct {
+		Interval string `json:"interval"`
+		RootDir  string `json:"directory"`
+		Restore  string `json:"restore"`
+	} `json:"checkpoints"`
+	Debug struct {
+		DumpToFile string `json:"dump-to-file"`
+		EnableGops bool   `json:"gops"`
+	} `json:"debug"`
+	RetentionInMemory string `json:"retention-in-memory"`
+	JwtPublicKey      string `json:"jwt-public-key"`
+	Archive           struct {
+		Interval      string `json:"interval"`
+		RootDir       string `json:"directory"`
+		DeleteInstead bool   `json:"delete-instead"`
+	} `json:"archive"`
+	Nats []*NatsConfig `json:"nats"`
+}
+
+func LoadConfiguration(file string) Config {
+	var config Config
+	configFile, err := os.Open(file)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer configFile.Close()
+	dec := json.NewDecoder(configFile)
+	dec.DisallowUnknownFields()
+	if err := dec.Decode(&config); err != nil {
+		log.Fatal(err)
+	}
+	return config
+}