Support plugin configuration via environment variables (#192)

Signed-off-by: Johannes Würbach <[email protected]>

src/jaegertracing/ConfigTest.cpp

@@ -19,6 +19,7 @@
 #include "jaegertracing/propagation/HeadersConfig.h"
 #include "jaegertracing/samplers/Config.h"
 #include "jaegertracing/utils/YAML.h"
+#include "jaegertracing/testutils/EnvVariable.h"
 #include <gtest/gtest.h>
 
 #include <cstdlib>
@@ -95,15 +96,6 @@ 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;
@@ -139,20 +131,20 @@ TEST(Config, testFromEnv)
     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");
+    testutils::EnvVariable::setEnv("JAEGER_AGENT_HOST", "host33");
+    testutils::EnvVariable::setEnv("JAEGER_AGENT_PORT", "45");
+    testutils::EnvVariable::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");
+    testutils::EnvVariable::setEnv("JAEGER_REPORTER_MAX_QUEUE_SIZE", "33");
+    testutils::EnvVariable::setEnv("JAEGER_REPORTER_FLUSH_INTERVAL", "45");
+    testutils::EnvVariable::setEnv("JAEGER_REPORTER_LOG_SPANS", "true");
 
-    setEnv("JAEGER_SAMPLER_TYPE", "remote");
-    setEnv("JAEGER_SAMPLER_PARAM", "0.33");
-    setEnv("JAEGER_SAMPLING_ENDPOINT", "http://myagent:1234");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLER_TYPE", "remote");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLER_PARAM", "0.33");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLING_ENDPOINT", "http://myagent:1234");
 
-    setEnv("JAEGER_SERVICE_NAME", "AService");
-    setEnv("JAEGER_TAGS", "hostname=foobar,my.app.version=4.5.6");
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "AService");
+    testutils::EnvVariable::setEnv("JAEGER_TAGS", "hostname=foobar,my.app.version=4.5.6");
 
     config.fromEnv();
 
@@ -179,13 +171,25 @@ TEST(Config, testFromEnv)
 
     ASSERT_EQ(false, config.disabled());
 
-    setEnv("JAEGER_DISABLED", "TRue");  // case-insensitive
-    setEnv("JAEGER_AGENT_PORT", "445");
+    testutils::EnvVariable::setEnv("JAEGER_DISABLED", "TRue");  // case-insensitive
+    testutils::EnvVariable::setEnv("JAEGER_AGENT_PORT", "445");
 
     config.fromEnv();
     ASSERT_EQ(true, config.disabled());
     ASSERT_EQ(std::string("host33:445"),
               config.reporter().localAgentHostPort());
+
+    testutils::EnvVariable::setEnv("JAEGER_AGENT_HOST", "");
+    testutils::EnvVariable::setEnv("JAEGER_AGENT_PORT", "");
+    testutils::EnvVariable::setEnv("JAEGER_ENDPOINT", "");
+    testutils::EnvVariable::setEnv("JAEGER_REPORTER_MAX_QUEUE_SIZE", "");
+    testutils::EnvVariable::setEnv("JAEGER_REPORTER_FLUSH_INTERVAL", "");
+    testutils::EnvVariable::setEnv("JAEGER_REPORTER_LOG_SPANS", "");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLER_PARAM", "");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLER_TYPE", "");
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
+    testutils::EnvVariable::setEnv("JAEGER_TAGS", "");
+    testutils::EnvVariable::setEnv("JAEGER_DISABLED", "");
 }
 
 }  // namespace jaegertracing

src/jaegertracing/DynamicLoad.cpp

@@ -41,7 +41,8 @@ static int makeTracerFactory(const char* opentracingVersion,
         return opentracing::incompatible_library_versions_error.value();
     }
 
-    *tracerFactory = new (std::nothrow) jaegertracing::TracerFactory{};
+    const auto jaegerTracerFactory = new (std::nothrow) jaegertracing::TracerFactory(true);
+    *tracerFactory = jaegerTracerFactory;
     if (*tracerFactory == nullptr) {
         *errorCategory = static_cast<const void*>(&std::generic_category());
         return static_cast<int>(std::errc::not_enough_memory);
@@ -50,4 +51,4 @@ static int makeTracerFactory(const char* opentracingVersion,
     return 0;
 }
 
-OPENTRACING_DECLARE_IMPL_FACTORY(makeTracerFactory)
+OPENTRACING_DECLARE_IMPL_FACTORY(makeTracerFactory)

src/jaegertracing/TracerFactory.cpp

@@ -38,19 +38,18 @@ TracerFactory::MakeTracer(const char* configuration,
             opentracing::configuration_parse_error);
     }
 
-    const auto serviceNameNode = yaml["service_name"];
-    if (!serviceNameNode) {
-        errorMessage = "`service_name` not provided";
-        return opentracing::make_unexpected(
-            opentracing::invalid_configuration_error);
+    auto tracerConfig = jaegertracing::Config::parse(yaml);
+
+    if (_readFromEnv) {
+        tracerConfig.fromEnv();
     }
-    if (!serviceNameNode.IsScalar()) {
-        errorMessage = "`service_name` must be a string";
+
+    if (tracerConfig.serviceName().empty()) {
+        errorMessage = "`service_name` not provided";
         return opentracing::make_unexpected(
             opentracing::invalid_configuration_error);
     }
 
-    const auto tracerConfig = jaegertracing::Config::parse(yaml);
     return jaegertracing::Tracer::make(tracerConfig);
 #endif  // JAEGERTRACING_WITH_YAML_CPP
 } catch (const std::bad_alloc&) {

src/jaegertracing/TracerFactory.h

@@ -26,6 +26,18 @@ class TracerFactory : public opentracing::TracerFactory {
     opentracing::expected<std::shared_ptr<opentracing::Tracer>>
     MakeTracer(const char* configuration, std::string& errorMessage) const
         noexcept override;
+
+    TracerFactory()
+        : TracerFactory(false)
+    {
+    }
+
+    TracerFactory(bool readFromEnv)
+        : _readFromEnv(readFromEnv)
+    {
+    }
+  private:
+    bool _readFromEnv;
 };
 
 }  // namespace jaegertracing

src/jaegertracing/TracerFactoryTest.cpp

@@ -14,8 +14,10 @@
  * limitations under the License.
  */
 
+#include "jaegertracing/Tracer.h"
 #include "jaegertracing/TracerFactory.h"
 #include "jaegertracing/Constants.h"
+#include "jaegertracing/testutils/EnvVariable.h"
 #include <gtest/gtest.h>
 
 namespace jaegertracing {
@@ -27,7 +29,7 @@ TEST(TracerFactory, testInvalidConfig)
                                              R"({
       "service_name": {}
     })" };
-    TracerFactory tracerFactory;
+    TracerFactory tracerFactory(true);
     for (auto&& invalidConfig : invalidConfigTestCases) {
         std::string errorMessage;
         auto tracerMaybe =
@@ -65,17 +67,68 @@ TEST(TracerFactory, testValidConfig)
         "refreshInterval": 60
     }
   })";
-    TracerFactory tracerFactory;
+    TracerFactory tracerFactory(true);
     std::string errorMessage;
     auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
     ASSERT_EQ(errorMessage, "");
     ASSERT_TRUE(tracerMaybe);
 }
+
+TEST(TracerFactory, testWithoutReadFromEnv)
+{
+    const char* config = "";
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "AService");
+    TracerFactory tracerFactory(false);
+    std::string errorMessage;
+    auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
+    ASSERT_FALSE(tracerMaybe);
+    ASSERT_NE(errorMessage, "");
+
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
+}
+
+TEST(TracerFactory, testWithReadFromEnv)
+{
+    const char* config = "";
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "AService");
+    TracerFactory tracerFactory(true);
+    std::string errorMessage;
+    auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
+    ASSERT_EQ(errorMessage, "");
+    ASSERT_TRUE(tracerMaybe);
+
+    auto tracer = tracerMaybe.value();
+    const auto jaegerTracer = std::dynamic_pointer_cast<jaegertracing::Tracer>(tracer);
+    ASSERT_EQ(std::string("AService"), jaegerTracer->serviceName());
+
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
+}
+
+TEST(TracerFactory, testEnvTakesPrecedence)
+{
+
+    const char* config = R"(
+  {
+    "service_name": "Ignored"
+  })";
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "test");
+    TracerFactory tracerFactory(true);
+    std::string errorMessage;
+    auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
+    ASSERT_EQ(errorMessage, "");
+    ASSERT_TRUE(tracerMaybe);
+
+    auto tracer = tracerMaybe.value();
+    const auto jaegerTracer = std::dynamic_pointer_cast<jaegertracing::Tracer>(tracer);
+    ASSERT_EQ(std::string("test"), jaegerTracer->serviceName());
+
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
+}
 #else
 TEST(TracerFactory, failsWithoutYAML)
 {
     const char* config = "";
-    TracerFactory tracerFactory;
+    TracerFactory tracerFactory(true);
     std::string errorMessage;
     auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
     ASSERT_NE(errorMessage, "");

src/jaegertracing/testutils/EnvVariable.cpp

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2019 The Jaeger 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.
+ */
+
+#include "jaegertracing/testutils/EnvVariable.h"

src/jaegertracing/testutils/EnvVariable.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2019 The Jaeger 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.
+ */
+
+#ifndef JAEGERTRACING_TESTUTILS_ENVVARIABLE_H
+#define JAEGERTRACING_TESTUTILS_ENVVARIABLE_H
+
+#include <string>
+
+namespace jaegertracing {
+namespace testutils {
+namespace EnvVariable {
+
+inline void setEnv(const char *variable, const char *value) {
+#ifdef WIN32
+  _putenv_s(variable, value);
+#else
+  setenv(variable, value, true);
+#endif
+}
+
+}  // namespace EnvVariable
+}  // namespace testutils
+}  // namespace jaegertracing
+
+#endif  // JAEGERTRACING_TESTUTILS_ENVVARIABLE_H

src/jaegertracing/utils/EnvVariable.h

@@ -62,4 +62,4 @@ inline std::pair<bool, bool> getBoolVariable(const char* envVar)
 }  // namespace utils
 }  // namespace jaegertracing
 
-#endif  // JAEGERTRACING_UTILS_HEXPARSING_H
+#endif  // JAEGERTRACING_UTILS_ENV_VARIABLE_H