Fix(bmqbrkr): Add --prefixDir argument to override BMQ_PREFIX

Signed-off-by: Patrick M. Niedzielski <pniedzielski@bloomberg.net>

Author: pniedzielski

src/applications/bmqbrkr/bmqbrkr.m.cpp

@@ -90,7 +90,7 @@ struct TaskEnvironment {
     // otherwise)
 
     bsl::string d_bmqPrefix;
-    // BMQ_PREFIX directory path
+    // Directory path to store PID, HIST, and CTL files under.
 
     bsl::string d_configJson;
     // JSON content ouput of the generated
@@ -414,7 +414,7 @@ static int initializeTask(bsl::ostream&    errorDescription,
                              bdlf::PlaceHolders::_1,    // prefix
                              bdlf::PlaceHolders::_2));  // istream
 
-    // Save the PID of the process in the '${BMQ_PREFIX}/bmqbrkr.pid' file
+    // Save the PID of the process in the '{prefix}/bmqbrkr.pid' file
     const bsl::string pidFile = taskEnv->d_bmqPrefix + "/bmqbrkr.pid";
     bsl::ofstream     pidFd(pidFile.c_str());
     if (!pidFd) {
@@ -499,9 +499,9 @@ static void shutdownApplication(TaskEnvironment* taskEnv)
     app.mqba::Application::~Application();
 }
 
-/// Update the `bmqbrkr.hist` file (in the BMQ_PREFIX directory) using the
+/// Update the `bmqbrkr.hist` file (in the prefix directory) using the
 /// specified `taskEnv`.  This file contains information about the last `n`
-/// successfull start of the broker, in reverse time order.
+/// successful starts of the broker, in reverse time order.
 /// Each line entry has the following format:
 ///    <currentTime_UTC>|<brokerVersion>|<configVersion>|<brokerId>
 ///
@@ -598,6 +598,7 @@ int main(int argc, const char* argv[])
 {
     // Parse command line parameters
     bsl::string configDir;
+    bsl::string prefixDir;
     bsl::string instanceId = "default";
     bsl::string hostName;
     bsl::string hostTags;
@@ -611,6 +612,11 @@ int main(int argc, const char* argv[])
          "Path to the configuration directory",
          balcl::TypeInfo(&configDir),
          balcl::OccurrenceInfo::e_REQUIRED},
+        {"",
+         "prefixDir",
+         "Path to the prefix directory (where PID, HIST, and CTL files live)",
+         balcl::TypeInfo(&prefixDir),
+         balcl::OccurrenceInfo::e_OPTIONAL},
         {"i|instanceId",
          "instanceId",
          "The instance ID ('default' if not provided)",
@@ -687,8 +693,11 @@ int main(int argc, const char* argv[])
     TaskEnvironment taskEnv;
     s_taskEnv_p = &taskEnv;
 
-    const char* prefixEnvVar = bsl::getenv("BMQ_PREFIX");
-    taskEnv.d_bmqPrefix      = (prefixEnvVar != 0 ? prefixEnvVar : "./");
+    // Default prefix directory to `BMQ_PREFIX` or ./
+    if (prefixDir.empty()) {
+        prefixDir = bsl::getenv("BMQ_PREFIX");
+    }
+    taskEnv.d_bmqPrefix      = (!prefixDir.empty() ? prefixDir : "./");
     taskEnv.d_instanceId     = instanceId;
 
     bmqu::MemOutStream errorDescription;

src/applications/bmqbrkr/m_bmqbrkr_task.h

@@ -199,7 +199,7 @@ class Task {
     // True is this object has been initialized.
 
     bsl::string d_bmqPrefix;
-    // BMQ_PREFIX directory
+    // Directory path to store PID, HIST, and CTL files under.
 
     bdlmt::EventScheduler d_scheduler;
     // EventScheduler