Printer: add force argument to force to print at least an empty entry

If you execute a search with negative matching the result could
contain hosts without the field. Under normal circumstances the entry
is not printed, because the filter_key does not exists. To get all the
matching entries an new force mode is added to print at lease an empty
entry.

2 files changed, 14 insertions, 7 deletions

diff --git a/bin/hostinfo b/bin/hostinfo
index 4a48e2b..0a36f67 100755
--- a/bin/hostinfo
+++ b/bin/hostinfo
@@ -97,12 +97,14 @@ def print_search(basepath, flags, search, filter_key=None):
 
             p = printer.Printer(data, flags)
             if filter_key is not None or flags.details:
-                p.info(filter_key, label=_get_label(host), maxlength=max(length))
+                p.info(filter_key, label=_get_label(host),
+                       maxlength=max(length), force=True)
             else:
                 if key is None:
                     print(_get_label(host))
                 else:
-                    p.info(key, label=_get_label(host), maxlength=max(length))
+                    p.info(key, label=_get_label(host),
+                           maxlength=max(length), force=True)
 
 def print_info(path, flags, key=None):
     data = _get_data(path)
diff --git a/hostinfo/printer.py b/hostinfo/printer.py
index 4302e04..d635d0a 100644
--- a/hostinfo/printer.py
+++ b/hostinfo/printer.py
@@ -82,14 +82,14 @@ class Printer:
         return (lambda key: self._should_display(_get_full_key(prev_key, key),
                                                  filter_key))
 
-    def _print(self, value, printer, filter_key=None, sort=None):
+    def _print(self, value, printer, filter_key=None, sort=None, force=False):
         try:
             value = value.strip().splitlines()
         except AttributeError:
             pass
 
         if isinstance(value, dict):
-            self._print_dict(value, printer, filter_key, sort)
+            self._print_dict(value, printer, filter_key, sort, force)
         elif isinstance(value, list):
             self._print_list(value, printer, filter_key)
         elif value is None:
@@ -126,7 +126,7 @@ class Printer:
             else:
                 self._print(value, printer, filter_key)
 
-    def _print_dict(self, value, printer, filter_key, sort):
+    def _print_dict(self, value, printer, filter_key, sort, force):
         keys = _sort_with_list(
             [(key, full_key) for key in value.keys()
              for full_key in [_get_full_key(printer.full_key, key)]
@@ -140,6 +140,7 @@ class Printer:
 
         _space(filter_key, printer.full_key, printer, True)
 
+        found = False
         for (key, full_key) in keys:
             new_filter_key = None
             if filter_key is not None:
@@ -148,6 +149,7 @@ class Printer:
                 elif full_key != filter_key:
                     continue
 
+            found = True
             new_printer = prefix.Printer(full_key, printer)
             if filter_key is None:
                 new_printer.set_label(self._get_label(key, full_key), maxlength)
@@ -155,15 +157,18 @@ class Printer:
             self._print_key(full_key, value[key], new_printer, new_filter_key)
             _space(filter_key, printer.full_key, new_printer)
 
+        if force and not found:
+            printer.pprint('')
+
     def _get_label(self, key, full_key):
         if full_key in self.labels:
             return self.labels[full_key]
         return key
 
-    def info(self, key, label=None, maxlength=0):
+    def info(self, key, label=None, maxlength=0, force=False):
         printer = prefix.Printer()
         if label is not None:
             printer.set_label(label, maxlength)
 
-        self._print(self.data, printer, filter_key=key,
+        self._print(self.data, printer, filter_key=key, force=force,
                     sort=['hostname', 'arch', 'os', 'addresses', 'ports'])