[exporter/loadbalancingexporter] support k8s service resolver

Signed-off-by: Yuan Fang <yuanfang@alauda.io>

cmd/otelcontribcol/go.mod

@@ -685,6 +685,7 @@ require (
 	k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f // indirect
 	k8s.io/kubelet v0.27.3 // indirect
 	k8s.io/utils v0.0.0-20230308161112-d77c459e9343 // indirect
+	sigs.k8s.io/controller-runtime v0.15.0 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
 	sigs.k8s.io/yaml v1.3.0 // indirect

exporter/loadbalancingexporter/README.md

@@ -28,13 +28,16 @@ This also supports service name based exporting for traces. If you have two or m
 Refer to [config.yaml](./testdata/config.yaml) for detailed examples on using the processor.
 
 * 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 `resolver` accepts a `static` node, a `dns` or a `k8s` node. If all three are specified, `k8s` 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 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 `k8s` node accepts the following optional properties:
+  * `service` Kubernetes service to resolve, e.g. `lb-svc.lb-ns`. If no namespace is specified, an attempt will be made to infer the namespace for this collector, and if this fails it will fall back to the `default` namespace.
+  * `ports` port to be used for exporting the traces to the addresses resolved from `service`. If `ports` is not specified, the default port 4317 is 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`.
@@ -83,6 +86,49 @@ service:
         - loadbalancing
 ```
 
+K8s resolver example
+```yaml
+receivers:
+  otlp:
+    protocols:
+      grpc:
+        endpoint: localhost:4317
+
+processors:
+
+exporters:
+  logging:
+  loadbalancing:
+    routing_key: "service"
+    protocol:
+      otlp:
+        # all options from the OTLP exporter are supported
+        # except the endpoint
+        timeout: 1s
+    resolver:
+      # use k8s service resolver, if collector runs in kubernetes environment
+      k8s:
+        service: lb-svc.kube-public
+        ports:
+          - 15317
+          - 16317
+
+service:
+  pipelines:
+    traces:
+      receivers:
+        - otlp
+      processors: []
+      exporters:
+        - loadbalancing
+    logs:
+      receivers:
+        - otlp
+      processors: []
+      exporters:
+        - loadbalancing
+```
+
 For testing purposes, the following configuration can be used, where both the load balancer and all backends are running locally:
 ```yaml
 receivers:

exporter/loadbalancingexporter/config.go

@@ -32,6 +32,7 @@ type Protocol struct {
 type ResolverSettings struct {
 	Static *StaticResolver `mapstructure:"static"`
 	DNS    *DNSResolver    `mapstructure:"dns"`
+	K8sSvc *K8sSvcResolver `mapstructure:"k8s"`
 }
 
 // StaticResolver defines the configuration for the resolver providing a fixed list of backends
@@ -46,3 +47,9 @@ type DNSResolver struct {
 	Interval time.Duration `mapstructure:"interval"`
 	Timeout  time.Duration `mapstructure:"timeout"`
 }
+
+// K8sSvcResolver defines the configuration for the DNS resolver
+type K8sSvcResolver struct {
+	Service string  `mapstructure:"service"`
+	Ports   []int32 `mapstructure:"ports"`
+}

exporter/loadbalancingexporter/go.mod

@@ -16,6 +16,11 @@ require (
 	go.opentelemetry.io/collector/semconv v0.80.0
 	go.uber.org/multierr v1.11.0
 	go.uber.org/zap v1.24.0
+	k8s.io/api v0.27.2
+	k8s.io/apimachinery v0.27.2
+	k8s.io/client-go v0.27.2
+	k8s.io/utils v0.0.0-20230209194617-a36077c30491
+	sigs.k8s.io/controller-runtime v0.15.0
 )
 
 require (
@@ -24,29 +29,43 @@ require (
 	github.com/cenkalti/backoff/v4 v4.2.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/emicklei/go-restful/v3 v3.9.0 // indirect
+	github.com/evanphx/json-patch v4.12.0+incompatible // indirect
+	github.com/evanphx/json-patch/v5 v5.6.0 // indirect
 	github.com/fsnotify/fsnotify v1.6.0 // indirect
 	github.com/go-kit/log v0.2.1 // indirect
 	github.com/go-logfmt/logfmt v0.5.1 // indirect
 	github.com/go-logr/logr v1.2.4 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-ole/go-ole v1.2.6 // indirect
+	github.com/go-openapi/jsonpointer v0.19.6 // indirect
+	github.com/go-openapi/jsonreference v0.20.1 // indirect
+	github.com/go-openapi/swag v0.22.3 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
+	github.com/google/gnostic v0.5.7-v3refs // indirect
+	github.com/google/go-cmp v0.5.9 // indirect
+	github.com/google/gofuzz v1.1.0 // indirect
 	github.com/google/uuid v1.3.0 // indirect
+	github.com/imdario/mergo v0.3.6 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/compress v1.16.6 // indirect
 	github.com/knadh/koanf v1.5.0 // indirect
 	github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/mostynb/go-grpc-compression v1.1.19 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
 	github.com/prometheus/client_golang v1.16.0 // indirect
@@ -86,14 +105,24 @@ require (
 	go.opentelemetry.io/otel/trace v1.16.0 // indirect
 	go.uber.org/atomic v1.10.0 // indirect
 	golang.org/x/net v0.11.0 // indirect
+	golang.org/x/oauth2 v0.8.0 // indirect
 	golang.org/x/sys v0.9.0 // indirect
+	golang.org/x/term v0.9.0 // indirect
 	golang.org/x/text v0.10.0 // indirect
+	golang.org/x/time v0.3.0 // indirect
 	gonum.org/v1/gonum v0.13.0 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20230530153820-e85fd2cbaebc // indirect
 	google.golang.org/grpc v1.56.0 // indirect
 	google.golang.org/protobuf v1.30.0 // indirect
+	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/klog/v2 v2.90.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f // indirect
+	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.2.3 // indirect
+	sigs.k8s.io/yaml v1.3.0 // indirect
 )
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/batchpersignal => ../../pkg/batchpersignal