Added environment variables as a source of Qpid configuration.

Option "foo-bar" will be read from env. QPID_FOO_BAR if
not specified on command line.


git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@532491 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 36 insertions, 2 deletions

diff --git a/cpp/src/qpid/CommonOptions.cpp b/cpp/src/qpid/CommonOptions.cpp
index 8efb3a6baa..d4db3660bd 100644
--- a/cpp/src/qpid/CommonOptions.cpp
+++ b/cpp/src/qpid/CommonOptions.cpp
@@ -17,9 +17,29 @@
  */
 
 #include "CommonOptions.h"
+#include <algorithm>
 
 namespace qpid {
 
+namespace program_options {
+
+char env2optchar(char env) {
+    return (env=='_') ? '-' : tolower(env);
+}
+    
+const std::string envPrefix("QPID_");
+
+std::string env2option(const std::string& env) {
+    if (env.find(envPrefix) ==0) {
+        std::string opt = env.substr(envPrefix.size());
+        std::transform(opt.begin(), opt.end(), opt.begin(), env2optchar);
+        return opt;
+    }
+    return std::string();
+} 
+
+} // namespace program_options
+
 const int CommonOptions::DEFAULT_PORT=5672;
 
 CommonOptions::CommonOptions() : trace(false), port(DEFAULT_PORT) {}
diff --git a/cpp/src/qpid/CommonOptions.h b/cpp/src/qpid/CommonOptions.h
index 2a4b9798cd..beaeb114e6 100644
--- a/cpp/src/qpid/CommonOptions.h
+++ b/cpp/src/qpid/CommonOptions.h
@@ -62,6 +62,11 @@ value_semantic* optValue(T& value, const char* arg) {
     return new OptionValue<T>(value, argName);
 }
 
+/** Environment-to-option name mapping.
+ * Maps env variable "QPID_SOME_VAR" to option "some-var"
+ */
+std::string env2option(const std::string& env);
+
 /**
  * Like boost::program_options::bool_switch but takes reference, not pointer.
  */
diff --git a/cpp/src/qpidd.cpp b/cpp/src/qpidd.cpp
index 8825f67233..d77b472ead 100644
--- a/cpp/src/qpidd.cpp
+++ b/cpp/src/qpidd.cpp
@@ -54,18 +54,27 @@ struct QpiddOptions : public Broker::Options
 
     void parse(int argc, char* argv[]) {
         po::variables_map vm;
+        // Earlier sources get precedence.
         po::store(po::parse_command_line(argc, argv, desc), vm);
+        try { 
+            po::store(po::parse_environment(desc, po::env2option), vm);
+        }
+        catch (const logic_error& e) {
+            // Make it clear this is an env. var problem, the
+            // exception from boost::program_options doesn't.
+            throw logic_error(string(e.what())+" (parsing environment variables)");
+        }
         po::notify(vm);
     };
     
-    void usage(std::ostream& out) const {
+    void usage(ostream& out) const {
         out << "Usage: qpidd [OPTIONS]" << endl 
             << "Start the Qpid AMQP broker." << endl << endl
             << desc << endl;
     };
 };
 
-std::ostream& operator<<(std::ostream& out, const QpiddOptions& config)  {
+ostream& operator<<(ostream& out, const QpiddOptions& config)  {
     config.usage(out); return out;
 }