Support Tracer tags and configuration via environment variables (#181)

* Support configuring client from environment variables (fix #178)

Signed-off-by: FR-MUREX-COM\mchaikhadouaihy <[email protected]>

* Apply Changes requested by @Yurishkhuro
1. When testing the config, start with a defined config instead of an empty one
2. Make sure fromEnv is harmful in case nothing is defined
3. Use literals to avoid fat-finger problem in the code
4. Avoid adding yet additional methods to the Tracer

Signed-off-by: FR-MUREX-COM\mchaikhadouaihy <[email protected]>

* Exclude sampler config.

Signed-off-by: FR-MUREX-COM\mchaikhadouaihy <[email protected]>

Author: mdouaihy

CMakeLists.txt

@@ -210,6 +210,7 @@ set(SRC
     src/jaegertracing/thrift-gen/zipkincore_types.cpp
     src/jaegertracing/utils/ErrorUtil.cpp
     src/jaegertracing/utils/HexParsing.cpp
+    src/jaegertracing/utils/EnvVariable.cpp
     src/jaegertracing/utils/RateLimiter.cpp
     src/jaegertracing/utils/UDPTransporter.cpp
     src/jaegertracing/utils/HTTPTransporter.cpp

README.md

@@ -86,6 +86,27 @@ sampler:
   samplingServerURL: http://jaeger-agent.local:5778
 ```
 
+### Configuration via Environment
+
+It's possible to populate the tracer configuration from the environement variables by calling `jaegertracing::Config::fromEnv`.
+
+The following property names are currently available:
+
+Property | Description
+--- | ---
+JAEGER_SERVICE_NAME | The service name
+JAEGER_DISABLED _(not recommended)_ | Instructs the Configuration to return a no-op tracer
+JAEGER_AGENT_HOST | The hostname for communicating with agent via UDP
+JAEGER_AGENT_PORT | The port for communicating with agent via UDP
+JAEGER_ENDPOINT | The traces endpoint, in case the client should connect directly to the Collector, like http://jaeger-collector:14268/api/traces
+JAEGER_REPORTER_LOG_SPANS | Whether the reporter should also log the spans
+JAEGER_REPORTER_MAX_QUEUE_SIZE | The reporter's maximum queue size
+JAEGER_REPORTER_FLUSH_INTERVAL | The reporter's flush interval (ms)
+JAEGER_SAMPLER_TYPE | The [sampler type](https://www.jaegertracing.io/docs/latest/sampling/#client-sampling-configuration)
+JAEGER_SAMPLER_PARAM | The sampler parameter (number)
+JAEGER_SAMPLER_MANAGER_HOST_PORT | The host name and port when using the remote controlled sampler
+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
+
 ## License
 
 [Apache 2.0 License](./LICENSE).

src/jaegertracing/Config.cpp

@@ -15,3 +15,53 @@
  */
 
 #include "jaegertracing/Config.h"
+#include "jaegertracing/samplers/Config.h"
+#include "jaegertracing/utils/EnvVariable.h"
+
+namespace jaegertracing {
+
+constexpr const char* Config::kJAEGER_SERVICE_NAME_ENV_PROP;
+constexpr const char* Config::kJAEGER_TAGS_ENV_PROP;
+constexpr const char* Config::kJAEGER_JAEGER_DISABLED_ENV_PROP;
+
+void Config::fromEnv()
+{
+    const auto disabled =
+        utils::EnvVariable::getBoolVariable(kJAEGER_JAEGER_DISABLED_ENV_PROP);
+    if (disabled.first) {
+        _disabled = disabled.second;
+    }
+
+    const auto serviceName =
+        utils::EnvVariable::getStringVariable(kJAEGER_SERVICE_NAME_ENV_PROP);
+    if (!serviceName.empty()) {
+        _serviceName = serviceName;
+    }
+
+    const auto tags =
+        utils::EnvVariable::getStringVariable(kJAEGER_TAGS_ENV_PROP);
+    if (!tags.empty()) {
+        std::string tag;
+        std::istringstream tagsStream(tags);
+        while (std::getline(tagsStream, tag, ',')) {
+
+            std::istringstream tagStream(tag);
+
+            std::string tagKey;
+            std::string tagValue;
+            if (std::getline(tagStream, tagKey, '=')) {
+                std::getline(tagStream, tagValue, '=');
+                if (std::getline(tagStream, tagValue, '=')) {
+                    // error, should be logged somewhere
+                }
+                else {
+                    _tags.emplace_back(tagKey, tagValue);
+                }
+            }
+        }
+    }
+    _reporter.fromEnv();
+    _sampler.fromEnv();
+}
+
+}  // namespace jaegertracing

src/jaegertracing/Config.h

@@ -19,6 +19,7 @@
 
 #include "jaegertracing/Compilers.h"
 #include "jaegertracing/Constants.h"
+#include "jaegertracing/Tag.h"
 #include "jaegertracing/baggage/RestrictionsConfig.h"
 #include "jaegertracing/propagation/HeadersConfig.h"
 #include "jaegertracing/reporters/Config.h"
@@ -29,6 +30,11 @@ namespace jaegertracing {
 
 class Config {
   public:
+
+    static constexpr auto kJAEGER_SERVICE_NAME_ENV_PROP = "JAEGER_SERVICE_NAME";
+    static constexpr auto kJAEGER_TAGS_ENV_PROP = "JAEGER_TAGS";
+    static constexpr auto kJAEGER_JAEGER_DISABLED_ENV_PROP = "JAEGER_DISABLED";
+
 #ifdef JAEGERTRACING_WITH_YAML_CPP
 
     static Config parse(const YAML::Node& configYAML)
@@ -37,6 +43,9 @@ class Config {
             return Config();
         }
 
+        const auto serviceName =
+            utils::yaml::findOrDefault<std::string>(configYAML, "service_name", "");
+
         const auto disabled =
             utils::yaml::findOrDefault<bool>(configYAML, "disabled", false);
         const auto samplerNode = configYAML["sampler"];
@@ -49,7 +58,7 @@ class Config {
         const auto baggageRestrictions =
             baggage::RestrictionsConfig::parse(baggageRestrictionsNode);
         return Config(
-            disabled, sampler, reporter, headers, baggageRestrictions);
+            disabled, sampler, reporter, headers, baggageRestrictions, serviceName);
     }
 
 #endif  // JAEGERTRACING_WITH_YAML_CPP
@@ -60,8 +69,12 @@ class Config {
                     const propagation::HeadersConfig& headers =
                         propagation::HeadersConfig(),
                     const baggage::RestrictionsConfig& baggageRestrictions =
-                        baggage::RestrictionsConfig())
+                        baggage::RestrictionsConfig(),
+                    const std::string& serviceName = "",
+                    const std::vector<Tag>&  tags = std::vector<Tag>())
         : _disabled(disabled)
+        , _serviceName(serviceName)
+        , _tags(tags)
         , _sampler(sampler)
         , _reporter(reporter)
         , _headers(headers)
@@ -82,8 +95,16 @@ class Config {
         return _baggageRestrictions;
     }
 
+    const std::string& serviceName() const { return _serviceName; }
+
+    const std::vector<Tag>& tags() const { return _tags; }
+
+    void fromEnv();
+
   private:
     bool _disabled;
+    std::string _serviceName;
+    std::vector< Tag > _tags;
     samplers::Config _sampler;
     reporters::Config _reporter;
     propagation::HeadersConfig _headers;

src/jaegertracing/ConfigTest.cpp

@@ -21,6 +21,8 @@
 #include "jaegertracing/utils/YAML.h"
 #include <gtest/gtest.h>
 
+#include <cstdlib>
+
 namespace jaegertracing {
 
 #ifdef JAEGERTRACING_WITH_YAML_CPP
@@ -93,4 +95,95 @@ TEST(Config, testZeroSamplingParam)
 
 #endif  // JAEGERTRACING_WITH_YAML_CPP
 
+
+void setEnv(const char *variable, const char *value) {
+#ifdef WIN32
+  _putenv_s(variable, value);
+#else
+  setenv(variable, value, true);
+#endif
+}
+
+TEST(Config, testFromEnv)
+{
+    std::vector<Tag> tags;
+    tags.emplace_back("hostname", std::string("foo"));
+    tags.emplace_back("my.app.version", std::string("1.2.3"));
+
+    Config config(false,
+                  samplers::Config("probabilistic",
+                                   0.7,
+                                   "http://host34:57/sampling",
+                                   0,
+                                   samplers::Config::Clock::duration()),
+                  reporters::Config(10,
+                                    std::chrono::milliseconds(100),
+                                    false,
+                                    "host35:77",
+                                    "http://host36:56568"),
+                  propagation::HeadersConfig(),
+                  baggage::RestrictionsConfig(),
+                  "test-service",
+                  tags);
+
+    config.fromEnv();
+
+    ASSERT_EQ(std::string("http://host36:56568"), config.reporter().endpoint());
+    ASSERT_EQ(std::string("host35:77"), config.reporter().localAgentHostPort());
+
+    ASSERT_EQ(10, config.reporter().queueSize());
+    ASSERT_EQ(std::chrono::milliseconds(100),
+              config.reporter().bufferFlushInterval());
+    ASSERT_EQ(false, config.reporter().logSpans());
+
+    ASSERT_EQ(.7, config.sampler().param());
+    ASSERT_EQ(std::string("probabilistic"), config.sampler().type());
+
+    setEnv("JAEGER_AGENT_HOST", "host33");
+    setEnv("JAEGER_AGENT_PORT", "45");
+    setEnv("JAEGER_ENDPOINT", "http://host34:56567");
+
+    setEnv("JAEGER_REPORTER_MAX_QUEUE_SIZE", "33");
+    setEnv("JAEGER_REPORTER_FLUSH_INTERVAL", "45");
+    setEnv("JAEGER_REPORTER_LOG_SPANS", "true");
+
+    setEnv("JAEGER_SAMPLER_PARAM", "33");
+    setEnv("JAEGER_SAMPLER_TYPE", "const");
+
+    setEnv("JAEGER_SERVICE_NAME", "AService");
+    setEnv("JAEGER_TAGS", "hostname=foobar,my.app.version=4.5.6");
+
+    config.fromEnv();
+
+    ASSERT_EQ(std::string("http://host34:56567"), config.reporter().endpoint());
+    ASSERT_EQ(std::string("host33:45"), config.reporter().localAgentHostPort());
+
+    ASSERT_EQ(33, config.reporter().queueSize());
+    ASSERT_EQ(std::chrono::milliseconds(45),
+              config.reporter().bufferFlushInterval());
+    ASSERT_EQ(true, config.reporter().logSpans());
+
+    ASSERT_EQ(33., config.sampler().param());
+    ASSERT_EQ(std::string("const"), config.sampler().type());
+
+    ASSERT_EQ(std::string("AService"), config.serviceName());
+
+    std::vector<Tag> expectedTags;
+    expectedTags.emplace_back("hostname", std::string("foo"));
+    expectedTags.emplace_back("my.app.version", std::string("1.2.3"));
+    expectedTags.emplace_back("hostname", std::string("foobar"));
+    expectedTags.emplace_back("my.app.version", std::string("4.5.6"));
+    ASSERT_EQ(expectedTags, config.tags());
+
+    ASSERT_EQ(false, config.disabled());
+
+    setEnv("JAEGER_DISABLED", "TRue");  // case-insensitive
+    setEnv("JAEGER_AGENT_PORT", "445");
+
+    config.fromEnv();
+    ASSERT_EQ(true, config.disabled());
+    ASSERT_EQ(std::string("host33:445"),
+              config.reporter().localAgentHostPort());
+}
+
 }  // namespace jaegertracing

src/jaegertracing/Tracer.cpp

@@ -239,6 +239,7 @@ Tracer::make(const std::string& serviceName,
                                               logger,
                                               metrics,
                                               config.headers(),
+                                              config.tags(),
                                               options));
 }
 

src/jaegertracing/Tracer.h

@@ -53,6 +53,13 @@ class Tracer : public opentracing::Tracer,
 
     static constexpr auto kGen128BitOption = 1;
 
+    static std::shared_ptr<opentracing::Tracer> make(const Config& config)
+    {
+        return make(config.serviceName(),
+                    config,
+                    std::shared_ptr<logging::Logger>(logging::nullLogger()));
+    }
+
     static std::shared_ptr<opentracing::Tracer>
     make(const std::string& serviceName, const Config& config)
     {
@@ -69,7 +76,6 @@ class Tracer : public opentracing::Tracer,
         metrics::NullStatsFactory factory;
         return make(serviceName, config, logger, factory);
     }
-
     static std::shared_ptr<opentracing::Tracer>
     make(const std::string& serviceName,
          const Config& config,
@@ -78,7 +84,6 @@ class Tracer : public opentracing::Tracer,
     {
         return make(serviceName, config, logger, statsFactory, 0);
     }
-
     static std::shared_ptr<opentracing::Tracer>
     make(const std::string& serviceName,
          const Config& config,
@@ -202,6 +207,7 @@ class Tracer : public opentracing::Tracer,
            const std::shared_ptr<logging::Logger>& logger,
            const std::shared_ptr<metrics::Metrics>& metrics,
            const propagation::HeadersConfig& headersConfig,
+           const std::vector<Tag>& tags,
            int options)
         : _serviceName(serviceName)
         , _hostIPv4(net::IPAddress::localIP(AF_INET))
@@ -233,6 +239,8 @@ class Tracer : public opentracing::Tracer,
             _tags.push_back(Tag(kTracerIPTagKey, _hostIPv4.host()));
         }
 
+        std::copy(tags.cbegin(), tags.cend(), std::back_inserter(_tags));
+
         std::random_device device;
         _randomNumberGenerator.seed(device());
     }

src/jaegertracing/TracerFactory.cpp

@@ -49,10 +49,9 @@ TracerFactory::MakeTracer(const char* configuration,
         return opentracing::make_unexpected(
             opentracing::invalid_configuration_error);
     }
-    std::string serviceName = serviceNameNode.Scalar();
 
     const auto tracerConfig = jaegertracing::Config::parse(yaml);
-    return jaegertracing::Tracer::make(serviceName, tracerConfig);
+    return jaegertracing::Tracer::make(tracerConfig);
 #endif  // JAEGERTRACING_WITH_YAML_CPP
 } catch (const std::bad_alloc&) {
     return opentracing::make_unexpected(

src/jaegertracing/TracerTest.cpp

@@ -416,4 +416,36 @@ TEST(Tracer, testPropagation)
     tracer->Close();
 }
 
+TEST(Tracer, testTracerTags)
+{
+    std::vector<Tag> tags;
+    tags.emplace_back("hostname", std::string("foobar"));
+    tags.emplace_back("my.app.version", std::string("1.2.3"));
+
+    Config config(
+        false,
+        samplers::Config(
+            "const", 1, "", 0, samplers::Config::Clock::duration()),
+        reporters::Config(0, std::chrono::milliseconds(100), false, "", ""),
+        propagation::HeadersConfig(),
+        baggage::RestrictionsConfig(),
+        "test-service",
+        tags);
+
+    auto tracer = Tracer::make(config);
+    const auto jaegerTracer = std::static_pointer_cast<Tracer>(tracer);
+
+    ASSERT_TRUE(std::find(jaegerTracer->tags().begin(),
+                          jaegerTracer->tags().end(),
+                          Tag("hostname", std::string("foobar"))) !=
+        jaegerTracer->tags().end());
+
+    ASSERT_TRUE(std::find(jaegerTracer->tags().begin(),
+                          jaegerTracer->tags().end(),
+                          Tag("my.app.version", std::string("1.2.3"))) !=
+        jaegerTracer->tags().end());
+
+    ASSERT_EQ(std::string("test-service"), jaegerTracer->serviceName());
+}
+
 }  // namespace jaegertracing

src/jaegertracing/net/IPAddress.h

@@ -53,7 +53,7 @@ namespace net {
 
 class IPAddress {
   public:
-    static IPAddress v4(const std::string& hostPort)
+    static std::pair<std::string, int> parse(const std::string& hostPort)
     {
         const auto colonPos = hostPort.find(':');
         const auto ip = hostPort.substr(0, colonPos);
@@ -65,7 +65,13 @@ class IPAddress {
                 port = 0;
             }
         }
-        return v4(ip, port);
+        return std::make_pair(ip, port);
+    }
+
+    static IPAddress v4(const std::string& hostPort)
+    {
+        auto result = parse(hostPort);
+        return v4(result.first, result.second);
     }
 
     static IPAddress v4(const std::string& ip, int port)