[exporter/loadbalancing] Allow interval and timeout to be customized

exporter/loadbalancingexporter/README.md

@@ -24,12 +24,15 @@ Refer to [config.yaml](./testdata/config.yaml) for detailed examples on using th
 * The `otlp` property configures the template used for building the OTLP exporter. Refer to the OTLP Exporter documentation for information on which options are available. Note that the `endpoint` property should not be set and will be overridden by this exporter with the backend endpoint.
 * The `resolver` accepts either a `static` node, or a `dns`. If both are specified, `dns` takes precedence.
 * The `hostname` property inside a `dns` node specifies the hostname to query in order to obtain the list of IP addresses.
-* The `dns` node also accepts an optional property `port` to specify the port to be used for exporting the traces to the IP addresses resolved from `hostname`. If `port` is not specified, the default port 4317 is used.
+* The `dns` node also accepts the following optional properties:
+  * `hostname` DNS hostname to resolve.
+  * `port` port to be used for exporting the traces to the IP addresses resolved from `hostname`. If `port` is not specified, the default port 4317 is used.
+  * `interval` resolver interval in go-Duration format, e.g. `5s`, `1d`, `30m`. If not specified, `5s` will be used.
+  * `timeout` resolver timeout in go-Duration format, e.g. `5s`, `1d`, `30m`. If not specified, `1s` will be used.
 * The `routing_key` property is used to route spans to exporters based on different parameters. This functionality is currently enabled only for `trace` pipeline types. It supports one of the following values:
     * `service`: exports spans based on their service name. This is useful when using processors like the span metrics, so all spans for each service are sent to consistent collector instances for metric collection. Otherwise, metrics for the same services are sent to different collectors, making aggregations inaccurate. 
     * `traceID` (default): exports spans based on their `traceID`.
     * If not configured, defaults to `traceID` based routing.
-
 
 Simple example
 ```yaml

exporter/loadbalancingexporter/config.go

@@ -15,6 +15,8 @@
 package loadbalancingexporter // import "github.com/open-telemetry/opentelemetry-collector-contrib/exporter/loadbalancingexporter"
 
 import (
+	"time"
+
 	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/exporter/otlpexporter"
 )
@@ -52,6 +54,8 @@ type StaticResolver struct {
 
 // DNSResolver defines the configuration for the DNS resolver
 type DNSResolver struct {
-	Hostname string `mapstructure:"hostname"`
-	Port     string `mapstructure:"port"`
+	Hostname string        `mapstructure:"hostname"`
+	Port     string        `mapstructure:"port"`
+	Interval time.Duration `mapstructure:"interval"`
+	Timeout  time.Duration `mapstructure:"timeout"`
 }

exporter/loadbalancingexporter/loadbalancer.go

@@ -79,7 +79,7 @@ func newLoadBalancer(params component.ExporterCreateSettings, cfg config.Exporte
 		dnsLogger := params.Logger.With(zap.String("resolver", "dns"))
 
 		var err error
-		res, err = newDNSResolver(dnsLogger, oCfg.Resolver.DNS.Hostname, oCfg.Resolver.DNS.Port)
+		res, err = newDNSResolver(dnsLogger, oCfg.Resolver.DNS.Hostname, oCfg.Resolver.DNS.Port, oCfg.Resolver.DNS.Interval, oCfg.Resolver.DNS.Timeout)
 		if err != nil {
 			return nil, err
 		}

exporter/loadbalancingexporter/log_exporter_test.go

@@ -342,7 +342,7 @@ func TestRollingUpdatesWhenConsumeLogs(t *testing.T) {
 
 	// simulate rolling updates, the dns resolver should resolve in the following order
 	// ["127.0.0.1"] -> ["127.0.0.1", "127.0.0.2"] -> ["127.0.0.2"]
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	mu := sync.Mutex{}

exporter/loadbalancingexporter/resolver_dns.go

@@ -59,18 +59,24 @@ type netResolver interface {
 	LookupIPAddr(ctx context.Context, host string) ([]net.IPAddr, error)
 }
 
-func newDNSResolver(logger *zap.Logger, hostname string, port string) (*dnsResolver, error) {
+func newDNSResolver(logger *zap.Logger, hostname string, port string, interval time.Duration, timeout time.Duration) (*dnsResolver, error) {
 	if len(hostname) == 0 {
 		return nil, errNoHostname
 	}
+	if interval == 0 {
+		interval = defaultResInterval
+	}
+	if timeout == 0 {
+		timeout = defaultResTimeout
+	}
 
 	return &dnsResolver{
 		logger:      logger,
 		hostname:    hostname,
 		port:        port,
 		resolver:    &net.Resolver{},
-		resInterval: defaultResInterval,
-		resTimeout:  defaultResTimeout,
+		resInterval: interval,
+		resTimeout:  timeout,
 		stopCh:      make(chan struct{}),
 	}, nil
 }
@@ -82,6 +88,9 @@ func (r *dnsResolver) start(ctx context.Context) error {
 
 	go r.periodicallyResolve()
 
+	r.logger.Debug("DNS resolver started",
+		zap.String("hostname", r.hostname), zap.String("port", r.port),
+		zap.Duration("interval", r.resInterval), zap.Duration("timeout", r.resTimeout))
 	return nil
 }
 
@@ -104,6 +113,8 @@ func (r *dnsResolver) periodicallyResolve() {
 			ctx, cancel := context.WithTimeout(context.Background(), r.resTimeout)
 			if _, err := r.resolve(ctx); err != nil {
 				r.logger.Warn("failed to resolve", zap.Error(err))
+			} else {
+				r.logger.Debug("resolved successfully")
 			}
 			cancel()
 		case <-r.stopCh:

exporter/loadbalancingexporter/resolver_dns_test.go

@@ -30,7 +30,7 @@ import (
 
 func TestInitialDNSResolution(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	res.resolver = &mockDNSResolver{
@@ -62,7 +62,7 @@ func TestInitialDNSResolution(t *testing.T) {
 
 func TestInitialDNSResolutionWithPort(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "55690")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "55690", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	res.resolver = &mockDNSResolver{
@@ -94,7 +94,7 @@ func TestInitialDNSResolutionWithPort(t *testing.T) {
 
 func TestErrNoHostname(t *testing.T) {
 	// test
-	res, err := newDNSResolver(zap.NewNop(), "", "")
+	res, err := newDNSResolver(zap.NewNop(), "", "", 5*time.Second, 1*time.Second)
 
 	// verify
 	assert.Nil(t, res)
@@ -103,7 +103,7 @@ func TestErrNoHostname(t *testing.T) {
 
 func TestCantResolve(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	expectedErr := errors.New("some expected error")
@@ -122,7 +122,7 @@ func TestCantResolve(t *testing.T) {
 
 func TestOnChange(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	resolve := []net.IPAddr{
@@ -189,7 +189,7 @@ func TestEqualStringSlice(t *testing.T) {
 
 func TestPeriodicallyResolve(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 10*time.Millisecond, 1*time.Second)
 	require.NoError(t, err)
 
 	counter := atomic.NewInt64(0)
@@ -224,7 +224,6 @@ func TestPeriodicallyResolve(t *testing.T) {
 			return resolve[0], nil
 		},
 	}
-	res.resInterval = 10 * time.Millisecond
 
 	wg := sync.WaitGroup{}
 	res.onChange(func(backends []string) {
@@ -248,7 +247,7 @@ func TestPeriodicallyResolve(t *testing.T) {
 
 func TestPeriodicallyResolveFailure(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 10*time.Millisecond, 1*time.Second)
 	require.NoError(t, err)
 
 	expectedErr := errors.New("some expected error")
@@ -273,7 +272,6 @@ func TestPeriodicallyResolveFailure(t *testing.T) {
 			return resolve, nil
 		},
 	}
-	res.resInterval = 10 * time.Millisecond
 
 	// test
 	wg.Add(2)
@@ -292,7 +290,7 @@ func TestPeriodicallyResolveFailure(t *testing.T) {
 
 func TestShutdownClearsCallbacks(t *testing.T) {
 	// prepare
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	res.resolver = &mockDNSResolver{}

exporter/loadbalancingexporter/trace_exporter_test.go

@@ -444,7 +444,7 @@ func TestRollingUpdatesWhenConsumeTraces(t *testing.T) {
 
 	// simulate rolling updates, the dns resolver should resolve in the following order
 	// ["127.0.0.1"] -> ["127.0.0.1", "127.0.0.2"] -> ["127.0.0.2"]
-	res, err := newDNSResolver(zap.NewNop(), "service-1", "")
+	res, err := newDNSResolver(zap.NewNop(), "service-1", "", 5*time.Second, 1*time.Second)
 	require.NoError(t, err)
 
 	mu := sync.Mutex{}

unreleased/add-dns-timer-configs.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: loadbalancingexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Added `interval` and `timeout` to the dns configuration in the loadbalancer exporter
+
+# One or more tracking issues related to the change
+issues: [10199]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: