global: split Akvorado into 3 services

configure/clickhouse/root.go

@@ -0,0 +1,80 @@
+// Package clickhouse handles configuration of the ClickHouse database.
+package clickhouse
+
+import (
+	"time"
+
+	"gopkg.in/tomb.v2"
+
+	"akvorado/common/daemon"
+	"akvorado/common/http"
+	"akvorado/common/reporter"
+)
+
+// Component represents the Kafka exporter.
+type Component struct {
+	r      *reporter.Reporter
+	d      *Dependencies
+	t      tomb.Tomb
+	config Configuration
+
+	migrationsDone chan bool
+}
+
+// Dependencies define the dependencies of the Kafka exporter.
+type Dependencies struct {
+	Daemon daemon.Component
+	HTTP   *http.Component
+}
+
+// New creates a new ClickHouse component.
+func New(reporter *reporter.Reporter, configuration Configuration, dependencies Dependencies) (*Component, error) {
+	c := Component{
+		r:              reporter,
+		d:              &dependencies,
+		config:         configuration,
+		migrationsDone: make(chan bool),
+	}
+	if err := c.registerHTTPHandlers(); err != nil {
+		return nil, err
+	}
+	c.d.Daemon.Track(&c.t, "configure/clickhouse")
+	return &c, nil
+}
+
+// Start the ClickHouse component
+func (c *Component) Start() error {
+	c.r.Info().Msg("starting ClickHouse component")
+	if err := c.migrateDatabase(); err != nil {
+		c.r.Warn().Msg("database migration failed, continue in the background")
+		c.t.Go(func() error {
+			for {
+				select {
+				case <-c.t.Dying():
+					return nil
+				case <-time.After(time.Minute):
+					c.r.Info().Msg("attempting database migration")
+					if err := c.migrateDatabase(); err == nil {
+						return nil
+					}
+				}
+			}
+		})
+	}
+	c.t.Go(func() error {
+		// We need at least one goroutine.
+		select {
+		case <-c.t.Dying():
+			return nil
+		}
+	})
+	return nil
+}
+
+// Stop stops the ClickHouse component
+func (c *Component) Stop() error {
+	c.r.Info().Msg("stopping ClickHouse component")
+	defer c.r.Info().Msg("ClickHouse component stopped")
+	c.t.Kill(nil)
+	return c.t.Wait()
+}