Support plugin configuration via environment variables

Signed-off-by: Johannes Würbach <johannes.wuerbach@googlemail.com>

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;
@@ -139,19 +131,19 @@ 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_PARAM", "33");
-    setEnv("JAEGER_SAMPLER_TYPE", "const");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLER_PARAM", "33");
+    testutils::EnvVariable::setEnv("JAEGER_SAMPLER_TYPE", "const");
 
-    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();
 
@@ -177,8 +169,8 @@ 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());

src/jaegertracing/TracerFactory.cpp

@@ -38,19 +38,16 @@ TracerFactory::MakeTracer(const char* configuration,
             opentracing::configuration_parse_error);
     }
 
-    const auto serviceNameNode = yaml["service_name"];
-    if (!serviceNameNode) {
+    auto tracerConfig = jaegertracing::Config::parse(yaml);
+
+    tracerConfig.fromEnv();
+
+    if (tracerConfig.serviceName().empty()) {
         errorMessage = "`service_name` not provided";
         return opentracing::make_unexpected(
             opentracing::invalid_configuration_error);
     }
-    if (!serviceNameNode.IsScalar()) {
-        errorMessage = "`service_name` must be a string";
-        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/TracerFactoryTest.cpp

@@ -16,12 +16,14 @@
 
 #include "jaegertracing/TracerFactory.h"
 #include "jaegertracing/Constants.h"
+#include "jaegertracing/testutils/EnvVariable.h"
 #include <gtest/gtest.h>
 
 namespace jaegertracing {
 #ifdef JAEGERTRACING_WITH_YAML_CPP
 TEST(TracerFactory, testInvalidConfig)
 {
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
     const char* invalidConfigTestCases[] = { "",
                                              "abc: {",
                                              R"({
@@ -65,12 +67,41 @@ TEST(TracerFactory, testValidConfig)
         "refreshInterval": 60
     }
   })";
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
     TracerFactory tracerFactory;
     std::string errorMessage;
     auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
     ASSERT_EQ(errorMessage, "");
     ASSERT_TRUE(tracerMaybe);
 }
+
+TEST(TracerFactory, testEnvironmentConfig)
+{
+    const char* config = "";
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "AService");
+    TracerFactory tracerFactory;
+    std::string errorMessage;
+    auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
+    ASSERT_EQ(errorMessage, "");
+    ASSERT_TRUE(tracerMaybe);
+}
+
+TEST(TracerFactory, testConfigAndEnvironment)
+{
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "");
+    const char* config = R"(
+  {
+    "service_name": "test"
+  })";
+    testutils::EnvVariable::setEnv("JAEGER_SERVICE_NAME", "AService");
+    TracerFactory tracerFactory;
+    std::string errorMessage;
+    auto tracerMaybe = tracerFactory.MakeTracer(config, errorMessage);
+    ASSERT_EQ(errorMessage, "");
+    ASSERT_TRUE(tracerMaybe);
+    ASSERT_EQ(tracerMaybe.serviceName(), "test")
+}
+
 #else
 TEST(TracerFactory, failsWithoutYAML)
 {

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 +1,41 @@
+/*
+ * 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>
+
+#include "jaegertracing/Tracer.h"
+#include "jaegertracing/testutils/MockAgent.h"
+
+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