make server options take environment variables

src/buildServerOptions.h

@@ -2,20 +2,58 @@
 #include <cstdlib>
 #include <memory>
 #include <string>
+#include <map>
+
 #include <folly/json.h>
 #include <folly/dynamic.h>
+#include <folly/Conv.h>
 #include <folly/DynamicConverter.h>
 #include <folly/FileUtil.h>
-
+#include <folly/MapUtil.h>
 #include "server/RelevanceServerOptions.h"
 #include "commandLineFlags.h"
 
+
 namespace relevanced {
 namespace server {
 
+std::map<std::string, std::string> getEnvSettings() {
+  std::map<std::string, std::string> envVarMap {
+    {"RELEVANCED_DATA_DIR", "data_dir"},
+    {"RELEVANCED_PORT", "port"},
+    {"RELEVANCED_CONFIG_FILE", "config_file"},
+    {"RELEVANCED_ROCKSDB_THREADS", "rocks_db_threads"},
+    {"RELEVANCED_DOCUMENT_PROCESSING_THREADS", "document_processing_threads"},
+    {"RELEVANCED_SIMILARITY_SCORE_THREADS", "similarity_score_threads"},
+    {"RELEVANCED_CENTROID_UPDATE_THREADS", "centroid_update_threads"}
+  };
+  std::map<std::string, std::string> output;
+  for (auto &elem: envVarMap) {
+    char *charVal = getenv(elem.first.c_str());
+    if (charVal != nullptr) {
+      std::string value = charVal;
+      output.insert(make_pair(elem.second, value));
+    }
+  }
+  return output;
+}
+
+// this is a little gross, but it's also a straightforward and
+// obvious way to do it. (and it's only run once on startup)
+
 std::shared_ptr<RelevanceServerOptions> buildOptions() {
   auto options = std::make_shared<RelevanceServerOptions>();
-  if (FLAGS_config_file.size() > 0) {
+  auto envSettings = getEnvSettings();
+
+  std::string configFilePath = FLAGS_config_file;
+  if (configFilePath.size() == 0) {
+    auto confPathOption = folly::get_optional(envSettings, "config_file");
+    if (confPathOption.hasValue()) {
+      configFilePath = confPathOption.value();
+    }
+  }
+
+  if (configFilePath.size() > 0) {
     std::string confStr;
     if (!folly::readFile(FLAGS_config_file.c_str(), confStr)) {
       LOG(INFO) << "error reading config file!";
@@ -52,6 +90,34 @@ std::shared_ptr<RelevanceServerOptions> buildOptions() {
     }
   }
 
+  {
+    // add any settings from the environment variables
+    auto envDataDir = folly::get_optional(envSettings, "data_dir");
+    if (envDataDir.hasValue()) {
+      options->setDataDir(envDataDir.value());
+    }
+    auto envPort = folly::get_optional(envSettings, "port");
+    if (envPort.hasValue()) {
+      options->setThriftPort(folly::to<int>(envPort.value()));
+    }
+    auto envRocksThreads = folly::get_optional(envSettings, "rocks_db_threads");
+    if (envRocksThreads.hasValue()) {
+      options->setRocksDbThreadCount(folly::to<int>(envRocksThreads.value()));
+    }
+    auto envUpdatingThreads = folly::get_optional(envSettings, "centroid_update_threads");
+    if (envUpdatingThreads.hasValue()) {
+      options->setCentroidUpdateThreadCount(folly::to<int>(envUpdatingThreads.value()));
+    }
+    auto envProcessingThreads = folly::get_optional(envSettings, "document_processing_threads");
+    if (envProcessingThreads.hasValue()) {
+      options->setDocumentProcessingThreadCount(folly::to<int>(envProcessingThreads.value()));
+    }
+    auto envScoringThreads = folly::get_optional(envSettings, "similarity_score_threads");
+    if (envScoringThreads.hasValue()) {
+      options->setSimilarityScoreThreadCount(folly::to<int>(envScoringThreads.value()));
+    }
+  }
+
   if (FLAGS_data_dir.size() > 0) {
     options->setDataDir(FLAGS_data_dir);
   }