Merge pull request #796 from XSAM/feature/jaeger-exporter-env

Add environment variables for Jaeger exporter

Author: shbieng

exporters/trace/jaeger/env.go

@@ -0,0 +1,163 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package jaeger
+
+import (
+	"errors"
+	"os"
+	"strconv"
+	"strings"
+
+	"go.opentelemetry.io/otel/api/global"
+	"go.opentelemetry.io/otel/api/kv"
+	"go.opentelemetry.io/otel/api/kv/value"
+)
+
+// Environment variable names
+const (
+	// The service name.
+	envServiceName = "JAEGER_SERVICE_NAME"
+	// Whether the exporter is disabled or not. (default false).
+	envDisabled = "JAEGER_DISABLED"
+	// A comma separated list of name=value tracer-level tags, which get added to all reported spans.
+	// The value can also refer to an environment variable using the format ${envVarName:defaultValue}.
+	envTags = "JAEGER_TAGS"
+	// The HTTP endpoint for sending spans directly to a collector,
+	// i.e. http://jaeger-collector:14268/api/traces.
+	envEndpoint = "JAEGER_ENDPOINT"
+	// Username to send as part of "Basic" authentication to the collector endpoint.
+	envUser = "JAEGER_USER"
+	// Password to send as part of "Basic" authentication to the collector endpoint.
+	envPassword = "JAEGER_PASSWORD"
+)
+
+// CollectorEndpointFromEnv return environment variable value of JAEGER_ENDPOINT
+func CollectorEndpointFromEnv() string {
+	return os.Getenv(envEndpoint)
+}
+
+// WithCollectorEndpointOptionFromEnv uses environment variables to set the username and password
+// if basic auth is required.
+func WithCollectorEndpointOptionFromEnv() CollectorEndpointOption {
+	return func(o *CollectorEndpointOptions) {
+		if e := os.Getenv(envUser); e != "" {
+			o.username = e
+		}
+		if e := os.Getenv(envPassword); e != "" {
+			o.password = os.Getenv(envPassword)
+		}
+	}
+}
+
+// WithDisabledFromEnv uses environment variables and overrides disabled field.
+func WithDisabledFromEnv() Option {
+	return func(o *options) {
+		if e := os.Getenv(envDisabled); e != "" {
+			if v, err := strconv.ParseBool(e); err == nil {
+				o.Disabled = v
+			}
+		}
+	}
+}
+
+// ProcessFromEnv parse environment variables into jaeger exporter's Process.
+// It will return a nil tag slice if the environment variable JAEGER_TAGS is malformed.
+func ProcessFromEnv() Process {
+	var p Process
+	if e := os.Getenv(envServiceName); e != "" {
+		p.ServiceName = e
+	}
+	if e := os.Getenv(envTags); e != "" {
+		tags, err := parseTags(e)
+		if err != nil {
+			global.Handle(err)
+		} else {
+			p.Tags = tags
+		}
+	}
+
+	return p
+}
+
+// WithProcessFromEnv uses environment variables and overrides jaeger exporter's Process.
+func WithProcessFromEnv() Option {
+	return func(o *options) {
+		p := ProcessFromEnv()
+		if p.ServiceName != "" {
+			o.Process.ServiceName = p.ServiceName
+		}
+		if len(p.Tags) != 0 {
+			o.Process.Tags = p.Tags
+		}
+	}
+}
+
+var errTagValueNotFound = errors.New("missing tag value")
+var errTagEnvironmentDefaultValueNotFound = errors.New("missing default value for tag environment value")
+
+// parseTags parses the given string into a collection of Tags.
+// Spec for this value:
+// - comma separated list of key=value
+// - value can be specified using the notation ${envVar:defaultValue}, where `envVar`
+// is an environment variable and `defaultValue` is the value to use in case the env var is not set
+func parseTags(sTags string) ([]kv.KeyValue, error) {
+	pairs := strings.Split(sTags, ",")
+	tags := make([]kv.KeyValue, len(pairs))
+	for i, p := range pairs {
+		field := strings.SplitN(p, "=", 2)
+		if len(field) != 2 {
+			return nil, errTagValueNotFound
+		}
+		k, v := strings.TrimSpace(field[0]), strings.TrimSpace(field[1])
+
+		if strings.HasPrefix(v, "${") && strings.HasSuffix(v, "}") {
+			ed := strings.SplitN(v[2:len(v)-1], ":", 2)
+			if len(ed) != 2 {
+				return nil, errTagEnvironmentDefaultValueNotFound
+			}
+			e, d := ed[0], ed[1]
+			v = os.Getenv(e)
+			if v == "" && d != "" {
+				v = d
+			}
+		}
+
+		tags[i] = parseKeyValue(k, v)
+	}
+
+	return tags, nil
+}
+
+func parseKeyValue(k, v string) kv.KeyValue {
+	return kv.KeyValue{
+		Key:   kv.Key(k),
+		Value: parseValue(v),
+	}
+}
+
+func parseValue(str string) value.Value {
+	if v, err := strconv.ParseInt(str, 10, 64); err == nil {
+		return value.Int64(v)
+	}
+	if v, err := strconv.ParseFloat(str, 64); err == nil {
+		return value.Float64(v)
+	}
+	if v, err := strconv.ParseBool(str); err == nil {
+		return value.Bool(v)
+	}
+
+	// Fallback
+	return value.String(str)
+}