.*: Add support for tracing with Lightstep (thanos-io#1678)

* Add support for tracing with Lightstep

Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

* Remove type cast

Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

* Add documentation for the exported methods and types

Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

* Apply suggestions from @bwplotka

Co-Authored-By: Bartlomiej Plotka <bwplotka@gmail.com>
Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

* Inline variable

Co-Authored-By: Povilas Versockas <p.versockas@gmail.com>
Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

* Update lightstep library and add proper error handling

lightstep/lightstep-tracer-go#228 introduced a
new method to create a Tracer that returns an error when it does not
succeed, instead of nil

Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

* Remove unused import

Signed-off-by: Antonio Santos <antonio@santosvelasco.com>

CHANGELOG.md

@@ -13,6 +13,7 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 
 ### Added
 
+- [#1678](https://github.com/thanos-io/thanos/pull/1678) Add Lightstep as a tracing provider.
 - [#1687](https://github.com/thanos-io/thanos/pull/1687) Add a new `--grpc-grace-period` CLI option to components which serve gRPC to set how long to wait until gRPC Server shuts down.
 - [#1660](https://github.com/thanos-io/thanos/pull/1660) Add a new `--prometheus.ready_timeout` CLI option to the sidecar to set how long to wait until Prometheus starts up.
 - [#1573](https://github.com/thanos-io/thanos/pull/1573) `AliYun OSS` object storage, see [documents](docs/storage.md#aliyun-oss) for further information.

docs/tracing.md

@@ -101,3 +101,22 @@ config:
   service_version: ""
   service_environment: ""
 ```
+
+### Lightstep
+
+Client for [Ligthstep](https://lightstep.com).
+
+In order to configure Thanos to interact with Lightstep you need to provide at least an [access token](https://docs.lightstep.com/docs/create-and-use-access-tokens) in the configuration file. The `collector` key is optional and used when you have on-premise satellites.
+
+[embedmd]:# (flags/config_tracing_lightstep.txt yaml)
+```yaml
+type: LIGHTSTEP
+config:
+  access_token: ""
+  collector:
+    scheme: ""
+    host: ""
+    port: 0
+    plaintext: false
+    custom_ca_cert_file: ""
+```

go.mod

@@ -49,6 +49,7 @@ require (
 	github.com/jstemmer/go-junit-report v0.9.1 // indirect
 	github.com/julienschmidt/httprouter v1.3.0 // indirect
 	github.com/leanovate/gopter v0.2.4
+	github.com/lightstep/lightstep-tracer-go v0.18.0
 	github.com/lovoo/gcloud-opentracing v0.3.0
 	github.com/mattn/go-ieproxy v0.0.0-20191113090002-7c0f6868bffe // indirect
 	github.com/mattn/go-runewidth v0.0.6 // indirect

pkg/tracing/client/factory.go

@@ -12,6 +12,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/thanos-io/thanos/pkg/tracing/elasticapm"
 	"github.com/thanos-io/thanos/pkg/tracing/jaeger"
+	"github.com/thanos-io/thanos/pkg/tracing/lightstep"
 	"github.com/thanos-io/thanos/pkg/tracing/stackdriver"
 	"gopkg.in/yaml.v2"
 )
@@ -22,6 +23,7 @@ const (
 	STACKDRIVER TracingProvider = "STACKDRIVER"
 	JAEGER      TracingProvider = "JAEGER"
 	ELASTIC_APM TracingProvider = "ELASTIC_APM"
+	LIGHTSTEP   TracingProvider = "LIGHTSTEP"
 )
 
 type TracingConfig struct {
@@ -53,6 +55,8 @@ func NewTracer(ctx context.Context, logger log.Logger, metrics *prometheus.Regis
 		return jaeger.NewTracer(ctx, logger, metrics, config)
 	case string(ELASTIC_APM):
 		return elasticapm.NewTracer(config)
+	case string(LIGHTSTEP):
+		return lightstep.NewTracer(ctx, config)
 	default:
 		return nil, nil, errors.Errorf("tracing with type %s is not supported", tracingConf.Type)
 	}

pkg/tracing/lightstep/lightstep.go

@@ -0,0 +1,57 @@
+package lightstep
+
+import (
+	"context"
+	"io"
+
+	"github.com/lightstep/lightstep-tracer-go"
+	"github.com/opentracing/opentracing-go"
+	"gopkg.in/yaml.v2"
+)
+
+// Config - YAML configuration.
+type Config struct {
+	// AccessToken is the unique API key for your LightStep project. It is
+	// available on your account page at https://app.lightstep.com/account.
+	AccessToken string `yaml:"access_token"`
+
+	// Collector is the host, port, and plaintext option to use
+	// for the collector.
+	Collector lightstep.Endpoint `yaml:"collector"`
+}
+
+// Tracer wraps the Lightstep tracer and the context.
+type Tracer struct {
+	lightstep.Tracer
+	ctx context.Context
+}
+
+// Close synchronously flushes the Lightstep tracer, then terminates it.
+func (t *Tracer) Close() error {
+	t.Tracer.Close(t.ctx)
+
+	return nil
+}
+
+// NewTracer creates a Tracer with the options present in the YAML config.
+func NewTracer(ctx context.Context, yamlConfig []byte) (opentracing.Tracer, io.Closer, error) {
+	config := Config{}
+	if err := yaml.Unmarshal(yamlConfig, &config); err != nil {
+		return nil, nil, err
+	}
+
+	options := lightstep.Options{
+		AccessToken: config.AccessToken,
+		Collector:   config.Collector,
+	}
+	lighstepTracer, err := lightstep.CreateTracer(options)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	t := &Tracer{
+		lighstepTracer,
+		ctx,
+	}
+	return t, t, nil
+}

scripts/cfggen/main.go

@@ -23,6 +23,7 @@ import (
 	trclient "github.com/thanos-io/thanos/pkg/tracing/client"
 	"github.com/thanos-io/thanos/pkg/tracing/elasticapm"
 	"github.com/thanos-io/thanos/pkg/tracing/jaeger"
+	"github.com/thanos-io/thanos/pkg/tracing/lightstep"
 	"github.com/thanos-io/thanos/pkg/tracing/stackdriver"
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 	yaml "gopkg.in/yaml.v2"
@@ -42,6 +43,7 @@ var (
 		trclient.JAEGER:      jaeger.Config{},
 		trclient.STACKDRIVER: stackdriver.Config{},
 		trclient.ELASTIC_APM: elasticapm.Config{},
+		trclient.LIGHTSTEP:   lightstep.Config{},
 	}
 )