Converge on JAEGER_SAMPLING_ENDPOINT env variable (#511)

* Converge on JAEGER_SAMPLING_ENDPOINT env variable

Signed-off-by: Eundoo Song <eundoo.song@gmail.com>

* Update config/config_env.go

Co-authored-by: Yuri Shkuro <yurishkuro@users.noreply.github.com>
Signed-off-by: Eundoo Song <eundoo.song@gmail.com>

Co-authored-by: Yuri Shkuro <yurishkuro@users.noreply.github.com>

README.md

@@ -60,7 +60,8 @@ JAEGER_REPORTER_MAX_QUEUE_SIZE | The reporter's maximum queue size
 JAEGER_REPORTER_FLUSH_INTERVAL | The reporter's flush interval, with units, e.g. "500ms" or "2s" ([valid units][timeunits])
 JAEGER_SAMPLER_TYPE | The sampler type
 JAEGER_SAMPLER_PARAM | The sampler parameter (number)
-JAEGER_SAMPLER_MANAGER_HOST_PORT | The HTTP endpoint when using the remote sampler, i.e. http://jaeger-agent:5778/sampling
+JAEGER_SAMPLER_MANAGER_HOST_PORT | (Deprecated) The HTTP endpoint when using the remote sampler
+JAEGER_SAMPLING_ENDPOINT | The url for the remote sampling conf when using sampler type remote. Default is http://127.0.0.1:5778/sampling
 JAEGER_SAMPLER_MAX_OPERATIONS | The maximum number of operations that the sampler will keep track of
 JAEGER_SAMPLER_REFRESH_INTERVAL | How often the remotely controlled sampler will poll jaeger-agent for the appropriate sampling strategy, with units, e.g. "1m" or "30s" ([valid units][timeunits])
 JAEGER_TAGS | 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:default}`, where the `:default` is optional, and identifies a value to be used if the environment variable cannot be found

config/config.go

@@ -72,12 +72,13 @@ type SamplerConfig struct {
 	// Can be set by exporting an environment variable named JAEGER_SAMPLER_PARAM
 	Param float64 `yaml:"param"`
 
-	// SamplingServerURL is the address of jaeger-agent's HTTP sampling server
-	// Can be set by exporting an environment variable named JAEGER_SAMPLER_MANAGER_HOST_PORT
+	// SamplingServerURL is the URL of sampling manager that can provide
+	// sampling strategy to this service.
+	// Can be set by exporting an environment variable named JAEGER_SAMPLING_ENDPOINT
 	SamplingServerURL string `yaml:"samplingServerURL"`
 
 	// SamplingRefreshInterval controls how often the remotely controlled sampler will poll
-	// jaeger-agent for the appropriate sampling strategy.
+	// sampling manager for the appropriate sampling strategy.
 	// Can be set by exporting an environment variable named JAEGER_SAMPLER_REFRESH_INTERVAL
 	SamplingRefreshInterval time.Duration `yaml:"samplingRefreshInterval"`
 

config/config_env.go

@@ -36,7 +36,8 @@ const (
 	envTags                   = "JAEGER_TAGS"
 	envSamplerType            = "JAEGER_SAMPLER_TYPE"
 	envSamplerParam           = "JAEGER_SAMPLER_PARAM"
-	envSamplerManagerHostPort = "JAEGER_SAMPLER_MANAGER_HOST_PORT"
+	envSamplerManagerHostPort = "JAEGER_SAMPLER_MANAGER_HOST_PORT" // Deprecated by envSamplingEndpoint
+	envSamplingEndpoint       = "JAEGER_SAMPLING_ENDPOINT"
 	envSamplerMaxOperations   = "JAEGER_SAMPLER_MAX_OPERATIONS"
 	envSamplerRefreshInterval = "JAEGER_SAMPLER_REFRESH_INTERVAL"
 	envReporterMaxQueueSize   = "JAEGER_REPORTER_MAX_QUEUE_SIZE"
@@ -118,7 +119,9 @@ func (sc *SamplerConfig) samplerConfigFromEnv() (*SamplerConfig, error) {
 		}
 	}
 
-	if e := os.Getenv(envSamplerManagerHostPort); e != "" {
+	if e := os.Getenv(envSamplingEndpoint); e != "" {
+		sc.SamplingServerURL = e
+	} else if e := os.Getenv(envSamplerManagerHostPort); e != "" {
 		sc.SamplingServerURL = e
 	} else if e := os.Getenv(envAgentHost); e != "" {
 		// Fallback if we know the agent host - try the sampling endpoint there

config/config_test.go

@@ -147,7 +147,7 @@ func TestSamplerConfig(t *testing.T) {
 	// prepare
 	setEnv(t, envSamplerType, "const")
 	setEnv(t, envSamplerParam, "1")
-	setEnv(t, envSamplerManagerHostPort, "http://themaster")
+	setEnv(t, envSamplingEndpoint, "http://themaster:5778/sampling")
 	setEnv(t, envSamplerMaxOperations, "10")
 	setEnv(t, envSamplerRefreshInterval, "1m1s") // 61 seconds
 
@@ -167,14 +167,14 @@ func TestSamplerConfig(t *testing.T) {
 	// verify
 	assert.Equal(t, "const", cfg.Type)
 	assert.Equal(t, float64(1), cfg.Param)
-	assert.Equal(t, "http://themaster", cfg.SamplingServerURL)
+	assert.Equal(t, "http://themaster:5778/sampling", cfg.SamplingServerURL)
 	assert.Equal(t, 10, cfg.MaxOperations)
 	assert.Equal(t, 61000000000, int(cfg.SamplingRefreshInterval))
 
 	// cleanup
 	unsetEnv(t, envSamplerType)
 	unsetEnv(t, envSamplerParam)
-	unsetEnv(t, envSamplerManagerHostPort)
+	unsetEnv(t, envSamplingEndpoint)
 	unsetEnv(t, envSamplerMaxOperations)
 	unsetEnv(t, envSamplerRefreshInterval)
 }
@@ -301,9 +301,9 @@ func TestNoServiceNameFromEnv(t *testing.T) {
 
 func TestSamplerConfigFromEnv(t *testing.T) {
 	// prepare
-	setEnv(t, envSamplerType, "const")
+	setEnv(t, envSamplerType, "remote")
 	setEnv(t, envSamplerParam, "1")
-	setEnv(t, envSamplerManagerHostPort, "http://themaster")
+	setEnv(t, envSamplingEndpoint, "http://themaster:5778/sampling")
 	setEnv(t, envSamplerMaxOperations, "10")
 	setEnv(t, envSamplerRefreshInterval, "1m1s") // 61 seconds
 
@@ -312,20 +312,35 @@ func TestSamplerConfigFromEnv(t *testing.T) {
 	assert.NoError(t, err)
 
 	// verify
-	assert.Equal(t, "const", cfg.Sampler.Type)
+	assert.Equal(t, "remote", cfg.Sampler.Type)
 	assert.Equal(t, float64(1), cfg.Sampler.Param)
-	assert.Equal(t, "http://themaster", cfg.Sampler.SamplingServerURL)
+	assert.Equal(t, "http://themaster:5778/sampling", cfg.Sampler.SamplingServerURL)
 	assert.Equal(t, 10, cfg.Sampler.MaxOperations)
 	assert.Equal(t, 61000000000, int(cfg.Sampler.SamplingRefreshInterval))
 
 	// cleanup
 	unsetEnv(t, envSamplerType)
 	unsetEnv(t, envSamplerParam)
-	unsetEnv(t, envSamplerManagerHostPort)
+	unsetEnv(t, envSamplingEndpoint)
 	unsetEnv(t, envSamplerMaxOperations)
 	unsetEnv(t, envSamplerRefreshInterval)
 }
 
+func TestDeprecatedSamplerConfigFromEnv(t *testing.T) {
+	// prepare
+	setEnv(t, envSamplerManagerHostPort, "http://themaster")
+
+	// test
+	cfg, err := FromEnv()
+	assert.NoError(t, err)
+
+	// verify
+	assert.Equal(t, "http://themaster", cfg.Sampler.SamplingServerURL)
+
+	// cleanup
+	unsetEnv(t, envSamplerManagerHostPort)
+}
+
 func TestSamplerConfigOnAgentFromEnv(t *testing.T) {
 	// prepare
 	setEnv(t, envAgentHost, "theagent")

constants.go

@@ -102,5 +102,5 @@ const (
 
 var (
 	// DefaultSamplingServerURL is the default url to fetch sampling config from, via http
-	DefaultSamplingServerURL = fmt.Sprintf("http://localhost:%d/sampling", DefaultSamplingServerPort)
+	DefaultSamplingServerURL = fmt.Sprintf("http://127.0.0.1:%d/sampling", DefaultSamplingServerPort)
 )