commit 3a429d91c39f468d25ade427b30f818edcc723d5
author Matthew Barth <msbarth@us.ibm.com> Thu Dec 05 16:58:27 2019 -0600
committer Matthew Barth <msbarth@us.ibm.com> Thu Jan 09 11:00:29 2020 -0600
tree a1104e6c9565e29a6f9f58e960b164a588f17e2b
parent 4fb0af98f3678c66cc043092a4dc9f89c855acc4

presence: Retrieve config file location from dbus

When configured with a dbus interface and property storing the file
location of the json configuration for fan presence, retrieve it from
the associated dbus object. The first dbus object found with the given
interface is used to get the file location from the given property
on that interface. Having more than one dbus object hosting the
interface with the configuration file location property is unsupported.

Tested:
    Config file is retrieved from defined dbus object

Change-Id: I82fbd622ded11da029ed9fdac8239a69a82370f8
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>

presence/json_config.cpp

diff --git a/presence/json_config.cpp b/presence/json_config.cpp
index d85f721..6dc06c2 100644
--- a/presence/json_config.cpp
+++ b/presence/json_config.cpp
@@ -53,8 +53,16 @@
 JsonConfig::JsonConfig(const std::string& jsonFile) :
     _defaultFile(fs::path(jsonFile))
 {
-    // Load and process the json configuration
-    load();
+    if (!_defaultFile.empty())
+    {
+        // Load and process the json configuration
+        load();
+    }
+    else
+    {
+        log<level::ERR>("No JSON config file provided");
+        throw std::runtime_error("No JSON config file provided");
+    }
 }
 
 const policies& JsonConfig::get()

presence/tach_detect.cpp

diff --git a/presence/tach_detect.cpp b/presence/tach_detect.cpp
index eb4b895..1636b9a 100644
--- a/presence/tach_detect.cpp
+++ b/presence/tach_detect.cpp
@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 #include "config.h"
-#ifdef PRESENCE_JSON_FILE
+#if defined(PRESENCE_JSON_FILE) || \
+    (defined(PRESENCE_JSON_DBUS_INTF) && defined(PRESENCE_JSON_DBUS_PROP))
 #include "json_config.hpp"
 #else
 #include "generated.hpp"
@@ -29,13 +30,36 @@
 {
     using namespace phosphor::fan;
 
+    auto bus = sdbusplus::bus::new_default();
     auto event = sdeventplus::Event::get_default();
-    util::SDBusPlus::getBus().attach_event(
-            event.get(), SD_EVENT_PRIORITY_NORMAL);
+    bus.attach_event(event.get(), SD_EVENT_PRIORITY_NORMAL);
 
 #ifdef PRESENCE_JSON_FILE
     // Use json file for presence config
     presence::JsonConfig config(PRESENCE_JSON_FILE);
+#elif defined(PRESENCE_JSON_DBUS_INTF) && defined(PRESENCE_JSON_DBUS_PROP)
+    // Use first object returned in the subtree
+    // (There should really only be one object with the config interface)
+    std::string jsonFile = "";
+    auto objects = util::SDBusPlus::getSubTree(
+        bus, "/", PRESENCE_JSON_DBUS_INTF, 0);
+    auto itObj = objects.begin();
+    if (itObj != objects.end())
+    {
+        auto itServ = itObj->second.begin();
+        if (itServ != itObj->second.end())
+        {
+            // Retrieve json config file location from dbus
+            jsonFile = util::SDBusPlus::getProperty<std::string>(
+                bus, itServ->first, itObj->first,
+                    PRESENCE_JSON_DBUS_INTF, PRESENCE_JSON_DBUS_PROP);
+        }
+    }
+    presence::JsonConfig config(jsonFile);
+#endif
+
+#if defined(PRESENCE_JSON_FILE) || \
+    (defined(PRESENCE_JSON_DBUS_INTF) && defined(PRESENCE_JSON_DBUS_PROP))
     for (auto& p: presence::JsonConfig::get())
     {
         p->monitor();