Fix parsing collection method from environment variables (#1886)

When read from an environment variable, the collection method was not
being canonicalized, leading to failing to parse it when the collection
method was in uppercase. Moved the canonicalization logic to a
ParseCollectionMethod and used that on args and environment variables.

collector/lib/CollectionMethod.cpp

@@ -1,6 +1,6 @@
 #include "CollectionMethod.h"
 
-#include <sstream>
+#include <algorithm>
 
 #include <sys/types.h>
 
@@ -24,4 +24,21 @@ const char* CollectionMethodName(CollectionMethod method) {
   }
 }
 
+CollectionMethod ParseCollectionMethod(std::string_view method) {
+  // Canonicalize collection method to lowercase, replace '-' with '_'
+  std::string cm(method);
+  std::transform(cm.begin(), cm.end(), cm.begin(), ::tolower);
+  std::replace(cm.begin(), cm.end(), '-', '_');
+
+  if (cm == "ebpf") {
+    return CollectionMethod::EBPF;
+  }
+
+  if (cm == "core_bpf") {
+    return CollectionMethod::CORE_BPF;
+  }
+
+  CLOG(WARNING) << "Invalid collection-method (" << cm << "), using CO-RE BPF";
+  return CollectionMethod::CORE_BPF;
+}
 }  // namespace collector

collector/lib/CollectionMethod.h

@@ -2,6 +2,7 @@
 #define COLLECTION_METHOD_H
 
 #include <ostream>
+#include <string_view>
 
 namespace collector {
 enum class CollectionMethod : uint8_t {
@@ -12,6 +13,7 @@ enum class CollectionMethod : uint8_t {
 std::ostream& operator<<(std::ostream& os, CollectionMethod method);
 
 const char* CollectionMethodName(CollectionMethod method);
+CollectionMethod ParseCollectionMethod(std::string_view method);
 
 }  // namespace collector
 

collector/lib/CollectorArgs.cpp

@@ -124,13 +124,9 @@ CollectorArgs::checkCollectionMethod(const option::Option& option, bool msg) {
     return ARG_OK;
   }
 
-  // Canonicalize collection method to lowercase, replace '-' with '_'
-  std::string s = option.arg;
-  std::transform(s.begin(), s.end(), s.begin(), ::tolower);
-  std::replace(s.begin(), s.end(), '-', '_');
-  collectionMethod = s;
+  collectionMethod = ParseCollectionMethod(option.arg);
 
-  CLOG(DEBUG) << "CollectionMethod: " << collectionMethod;
+  CLOG(DEBUG) << "CollectionMethod: " << CollectionMethodName(collectionMethod.value());
 
   return ARG_OK;
 }
@@ -174,7 +170,7 @@ CollectorArgs::CollectorConfig() const {
   return collectorConfig;
 }
 
-const std::string&
+std::optional<CollectionMethod>
 CollectorArgs::GetCollectionMethod() const {
   return collectionMethod;
 }

collector/lib/CollectorArgs.h

@@ -1,10 +1,12 @@
 #ifndef _COLLECTOR_ARGS_H_
 #define _COLLECTOR_ARGS_H_
 
+#include <optional>
 #include <string>
 
 #include <json/json.h>
 
+#include "CollectionMethod.h"
 #include "optionparser.h"
 
 namespace collector {
@@ -22,7 +24,7 @@ class CollectorArgs {
   option::ArgStatus checkOptionalNumeric(const option::Option& option, bool msg);
 
   const Json::Value& CollectorConfig() const;
-  const std::string& GetCollectionMethod() const;
+  std::optional<CollectionMethod> GetCollectionMethod() const;
   const std::string& GRPCServer() const;
   const std::string& Message() const;
 
@@ -33,7 +35,7 @@ class CollectorArgs {
   static CollectorArgs* instance;
 
   Json::Value collectorConfig;
-  std::string collectionMethod;
+  std::optional<CollectionMethod> collectionMethod{std::nullopt};
   std::string message;
   std::string grpcServer;
 };

collector/lib/CollectorConfig.cpp

@@ -6,6 +6,7 @@
 
 #include <libsinsp/sinsp.h>
 
+#include "CollectionMethod.h"
 #include "CollectorArgs.h"
 #include "EnvVar.h"
 #include "GRPC.h"
@@ -186,22 +187,15 @@ void CollectorConfig::InitCollectorConfig(CollectorArgs* args) {
     }
 
     // Collection Method
-    auto setCollectionMethod = [&](const std::string& cm) {
-      CLOG(INFO) << "User configured collection-method=" << cm;
-      if (cm == "ebpf") {
-        collection_method_ = CollectionMethod::EBPF;
-      } else if (cm == "core_bpf") {
-        collection_method_ = CollectionMethod::CORE_BPF;
-      } else {
-        CLOG(WARNING) << "Invalid collection-method (" << cm << "), using CO-RE BPF";
-        collection_method_ = CollectionMethod::CORE_BPF;
-      }
+    auto setCollectionMethod = [&](const CollectionMethod cm) {
+      CLOG(INFO) << "User configured collection-method=" << CollectionMethodName(cm);
+      collection_method_ = cm;
     };
 
-    if (args->GetCollectionMethod().length() > 0) {
-      setCollectionMethod(args->GetCollectionMethod());
+    if (args->GetCollectionMethod()) {
+      setCollectionMethod(args->GetCollectionMethod().value());
     } else if (collection_method.hasValue()) {
-      setCollectionMethod(collection_method.value());
+      setCollectionMethod(ParseCollectionMethod(collection_method.value()));
     }
 
     // TLS configuration