Add non-blocking InfluxDB sink (#29)

* Add non-blocking InfluxDB sink

* Add configurable batch size

sinks/influxAsyncSink.go

@@ -0,0 +1,119 @@
+package sinks
+
+import (
+	//	"context"
+	"crypto/tls"
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	cclog "github.com/ClusterCockpit/cc-metric-collector/internal/ccLogger"
+	lp "github.com/ClusterCockpit/cc-metric-collector/internal/ccMetric"
+	influxdb2 "github.com/influxdata/influxdb-client-go/v2"
+	influxdb2Api "github.com/influxdata/influxdb-client-go/v2/api"
+	"github.com/influxdata/influxdb-client-go/v2/api/write"
+)
+
+type InfluxAsyncSinkConfig struct {
+	defaultSinkConfig
+	Host         string `json:"host,omitempty"`
+	Port         string `json:"port,omitempty"`
+	Database     string `json:"database,omitempty"`
+	User         string `json:"user,omitempty"`
+	Password     string `json:"password,omitempty"`
+	Organization string `json:"organization,omitempty"`
+	SSL          bool   `json:"ssl,omitempty"`
+	RetentionPol string `json:"retention_policy,omitempty"`
+	BatchSize    uint   `json:"batch_size,omitempty"`
+}
+
+type InfluxAsyncSink struct {
+	sink
+	client    influxdb2.Client
+	writeApi  influxdb2Api.WriteAPI
+	retPolicy string
+	errors    <-chan error
+	config    InfluxAsyncSinkConfig
+}
+
+func (s *InfluxAsyncSink) connect() error {
+	var auth string
+	var uri string
+	if s.config.SSL {
+		uri = fmt.Sprintf("https://%s:%s", s.config.Host, s.config.Port)
+	} else {
+		uri = fmt.Sprintf("http://%s:%s", s.config.Host, s.config.Port)
+	}
+	if len(s.config.User) == 0 {
+		auth = s.config.Password
+	} else {
+		auth = fmt.Sprintf("%s:%s", s.config.User, s.config.Password)
+	}
+	cclog.ComponentDebug(s.name, "Using URI", uri, "Org", s.config.Organization, "Bucket", s.config.Database)
+	batch := s.config.BatchSize
+	if batch == 0 {
+		batch = 100
+	}
+	s.client = influxdb2.NewClientWithOptions(uri, auth,
+		influxdb2.DefaultOptions().SetBatchSize(batch).SetTLSConfig(&tls.Config{
+			InsecureSkipVerify: true,
+		}))
+	s.writeApi = s.client.WriteAPI(s.config.Organization, s.config.Database)
+	return nil
+}
+
+func (s *InfluxAsyncSink) Init(config json.RawMessage) error {
+	s.name = "InfluxSink"
+	s.config.BatchSize = 100
+	if len(config) > 0 {
+		err := json.Unmarshal(config, &s.config)
+		if err != nil {
+			return err
+		}
+	}
+	if len(s.config.Host) == 0 ||
+		len(s.config.Port) == 0 ||
+		len(s.config.Database) == 0 ||
+		len(s.config.Organization) == 0 ||
+		len(s.config.Password) == 0 {
+		return errors.New("not all configuration variables set required by InfluxAsyncSink")
+	}
+	err := s.connect()
+	s.errors = s.writeApi.Errors()
+	go func() {
+		for err := range s.errors {
+			cclog.ComponentError(s.name, err.Error())
+		}
+	}()
+	return err
+}
+
+func (s *InfluxAsyncSink) Write(point lp.CCMetric) error {
+	var p *write.Point
+	if s.config.MetaAsTags {
+		tags := map[string]string{}
+		for k, v := range point.Tags() {
+			tags[k] = v
+		}
+		for k, v := range point.Meta() {
+			tags[k] = v
+		}
+		p = influxdb2.NewPoint(point.Name(), tags, point.Fields(), point.Time())
+	} else {
+		p = influxdb2.NewPoint(point.Name(), point.Tags(), point.Fields(), point.Time())
+	}
+
+	s.writeApi.WritePoint(p)
+	return nil
+}
+
+func (s *InfluxAsyncSink) Flush() error {
+	s.writeApi.Flush()
+	return nil
+}
+
+func (s *InfluxAsyncSink) Close() {
+	cclog.ComponentDebug(s.name, "Closing InfluxDB connection")
+	s.writeApi.Flush()
+	s.client.Close()
+}

sinks/influxAsyncSink.md

@@ -0,0 +1,34 @@
+## `influxasync` sink
+
+The `influxasync` sink uses the official [InfluxDB golang client](https://pkg.go.dev/github.com/influxdata/influxdb-client-go/v2) to write the metrics to an InfluxDB database in a **non-blocking** fashion. It provides only support for V2 write endpoints (InfluxDB 1.8.0 or later).
+
+
+### Configuration structure
+
+```json
+{
+  "<name>": {
+    "type": "influxasync",
+    "meta_as_tags" : true,
+    "database" : "mymetrics",
+    "host": "dbhost.example.com",
+    "port": "4222",
+    "user": "exampleuser",
+    "password" : "examplepw",
+    "organization": "myorg",
+    "ssl": true,
+    "batch_size": 200,
+  }
+}
+```
+
+- `type`: makes the sink an `influxdb` sink
+- `meta_as_tags`: print all meta information as tags in the output (optional)
+- `database`: All metrics are written to this bucket 
+- `host`: Hostname of the InfluxDB database server
+- `port`: Portnumber (as string) of the InfluxDB database server
+- `user`: Username for basic authentification
+- `password`: Password for basic authentification
+- `organization`: Organization in the InfluxDB
+- `ssl`: Use SSL connection
+- `batch_size`: batch up metrics internally, default 100

sinks/influxSink.md

@@ -1,6 +1,6 @@
 ## `influxdb` sink
 
-The `influxdb` sink uses the official [InfluxDB golang client](https://pkg.go.dev/github.com/influxdata/influxdb-client-go/v2) to write the metrics to an InfluxDB database. It provides only support for V2 write endpoints (InfluxDB 1.8.0 or later).
+The `influxdb` sink uses the official [InfluxDB golang client](https://pkg.go.dev/github.com/influxdata/influxdb-client-go/v2) to write the metrics to an InfluxDB database in a **blocking** fashion. It provides only support for V2 write endpoints (InfluxDB 1.8.0 or later).
 
 
 ### Configuration structure

sinks/sinkManager.go

@@ -17,6 +17,7 @@ var AvailableSinks = map[string]Sink{
 	"nats":        new(NatsSink),
 	"http":        new(HttpSink),
 	"ganglia":     new(GangliaSink),
+	"influxasync": new(InfluxAsyncSink),
 }
 
 // Metric collector manager data structure