[process-reboot-cause] Handle case if platform does not yet have soni…

…c_platform implementation (#3126)

files/image_config/process-reboot-cause/process-reboot-cause

@@ -9,33 +9,49 @@
 try:
     import os
     import pwd
-    import subprocess
     import sys
     import syslog
-    import sonic_platform
-    from sonic_daemon_base.daemon_base import Logger
 except ImportError as err:
     raise ImportError("%s - required module not found" % str(err))
 
 VERSION = "1.0"
 
 SYSLOG_IDENTIFIER = "process-reboot-cause"
 
-# Global logger instance
-logger = Logger(SYSLOG_IDENTIFIER)
-
 REBOOT_CAUSE_DIR = "/host/reboot-cause/"
 REBOOT_CAUSE_FILE = REBOOT_CAUSE_DIR + "reboot-cause.txt"
 PREVIOUS_REBOOT_CAUSE_FILE = REBOOT_CAUSE_DIR + "previous-reboot-cause.txt"
 
 UNKNOWN_REBOOT_CAUSE = "Unknown"
 
 
+# ========================== Syslog wrappers ==========================
+
+def log_info(msg):
+    syslog.openlog(SYSLOG_IDENTIFIER)
+    syslog.syslog(syslog.LOG_INFO, msg)
+    syslog.closelog()
+
+
+def log_warning(msg):
+    syslog.openlog(SYSLOG_IDENTIFIER)
+    syslog.syslog(syslog.LOG_WARNING, msg)
+    syslog.closelog()
+
+
+def log_error(msg):
+    syslog.openlog(SYSLOG_IDENTIFIER)
+    syslog.syslog(syslog.LOG_ERR, msg)
+    syslog.closelog()
+
+
+# ============================= Functions =============================
+
 def main():
-    logger.log_info("Starting up...")
+    log_info("Starting up...")
 
     if not os.geteuid() == 0:
-        logger.log_error("User {} does not have permission to execute".format(pwd.getpwuid(os.getuid()).pw_name))
+        log_error("User {} does not have permission to execute".format(pwd.getpwuid(os.getuid()).pw_name))
         sys.exit("This utility must be run as root")
 
     # Create REBOOT_CAUSE_DIR if it doesn't exist
@@ -46,35 +62,51 @@ def main():
     if os.path.exists(PREVIOUS_REBOOT_CAUSE_FILE):
         os.remove(PREVIOUS_REBOOT_CAUSE_FILE)
 
-    # Check if the previous reboot was caused by hardware
-    platform = sonic_platform.platform.Platform()
-
-    chassis = platform.get_chassis()
-
-    hardware_reboot_cause, optional_details = chassis.get_reboot_cause()
 
     # Set a default previous reboot cause
     previous_reboot_cause = UNKNOWN_REBOOT_CAUSE
 
-    if hardware_reboot_cause == chassis.REBOOT_CAUSE_NON_HARDWARE:
-        # The reboot was not caused by hardware. If there is a REBOOT_CAUSE_FILE, it will
-        # contain any software-related reboot info. We will use it as the previous cause.
+    # Until all platform vendors have provided sonic_platform packages,
+    # if there is no sonic_platform package installed, we only provide
+    # software-related reboot causes.
+    try:
+        import sonic_platform
+
+        # Check if the previous reboot was caused by hardware
+        platform = sonic_platform.platform.Platform()
+
+        chassis = platform.get_chassis()
+
+        hardware_reboot_cause, optional_details = chassis.get_reboot_cause()
+
+        if hardware_reboot_cause == chassis.REBOOT_CAUSE_NON_HARDWARE:
+            # The reboot was not caused by hardware. If there is a REBOOT_CAUSE_FILE, it will
+            # contain any software-related reboot info. We will use it as the previous cause.
+            if os.path.isfile(REBOOT_CAUSE_FILE):
+                cause_file = open(REBOOT_CAUSE_FILE, "r")
+                previous_reboot_cause = cause_file.readline().rstrip('\n')
+                cause_file.close()
+        elif hardware_reboot_cause == chassis.REBOOT_CAUSE_HARDWARE_OTHER:
+            previous_reboot_cause = "{} ({})".format(hardware_reboot_cause, optional_details)
+        else:
+            previous_reboot_cause = hardware_reboot_cause
+    except ImportError as err:
+        log_warning("sonic_platform package not installed. Unable to detect hardware reboot causes.")
+
+        # If there is a REBOOT_CAUSE_FILE, it will contain any software-related
+        # reboot info. We will use it as the previous cause.
         if os.path.isfile(REBOOT_CAUSE_FILE):
             cause_file = open(REBOOT_CAUSE_FILE, "r")
             previous_reboot_cause = cause_file.readline().rstrip('\n')
             cause_file.close()
-    elif hardware_reboot_cause == chassis.REBOOT_CAUSE_HARDWARE_OTHER:
-        previous_reboot_cause = "{} ({})".format(hardware_reboot_cause, optional_details)
-    else:
-        previous_reboot_cause = hardware_reboot_cause
 
     # Write the previous reboot cause to PREVIOUS_REBOOT_CAUSE_FILE
     prev_cause_file = open(PREVIOUS_REBOOT_CAUSE_FILE, "w")
     prev_cause_file.write(previous_reboot_cause)
     prev_cause_file.close()
 
     # Also log the previous reboot cause to the syslog
-    logger.log_info("Previous reboot cause: {}".format(previous_reboot_cause))
+    log_info("Previous reboot cause: {}".format(previous_reboot_cause))
 
     # Remove the old REBOOT_CAUSE_FILE
     os.remove(REBOOT_CAUSE_FILE)