Add support for --tags and --tag TAGNAME in the ec2metadata script

bin/ec2metadata

@@ -35,7 +35,8 @@ except ImportError:
 
 
 instdata_host = "169.254.169.254"
-instdata_ver = "2009-04-04"
+#instdata_ver = "2009-04-04"
+instdata_ver = "latest"
 instdata_url = "http://%s/%s" % (instdata_host, instdata_ver)
 
 TOKEN_TTL_SECONDS = 21600
@@ -87,8 +88,12 @@ Options:
     --public-keys           display the openssh public keys
     --user-data             display the user data (not actually metadata)
 
+    --tags                  dispaly the instance tags if enabled
+
     -u | --url URL          use URL (default: %s)
 
+    -t | --tag TAGNAME      display a specific instance tag
+
 """ % instdata_url
 
 
@@ -99,7 +104,7 @@ METAOPTS = ['ami-id', 'ami-launch-index', 'ami-manifest-path',
             'profile', 'product-codes', 'public-hostname', 'public-ipv4',
             'public-keys', 'ramdisk-id', 'reservation-id', 'security-groups',
             'user-data', 'availability-zone-id', 'region', 'host-id',
-            'group-name', 'partition-number']
+            'group-name', 'partition-number', 'tags']
 
 binstdout = os.fdopen(sys.stdout.fileno(), 'wb')
 
@@ -118,8 +123,9 @@ class Error(Exception):
 class EC2Metadata:  # pylint: disable=R0903
     """Class for querying metadata from EC2"""
 
-    def __init__(self, burl=instdata_url):
+    def __init__(self, burl=instdata_url, tagvalue=''):
         self.burl = burl
+        self.tagvalue = tagvalue
 
         s = urllib_parse.urlsplit(burl)
         addr = s.netloc.split(":")[0]
@@ -176,6 +182,28 @@ class EC2Metadata:  # pylint: disable=R0903
     def get(self, metaopt):
         """return value of metaopt"""
 
+        if metaopt in ['tags', 'tag']:
+            if metaopt == 'tags':
+                data = self._get('meta-data/tags/instance')
+
+                if data is None:
+                    return None
+
+                splitlines = data.splitlines()
+
+                tag_key_values = []
+
+                tag_key_values = []
+                for tag_name in data.splitlines():
+                    uri = 'meta-data/tags/instance/%s' % tag_name
+                    tag_key_values.append("%s=" % tag_name + self._get(uri).rstrip())
+
+                return '\n'.join(tag_key_values)
+            else:
+                data = self._get('meta-data/tags/instance/%s' % self.tagvalue)
+
+                return data
+
         if metaopt not in METAOPTS:
             raise Error('unknown metaopt', metaopt, METAOPTS)
 
@@ -216,10 +244,10 @@ def get(metaopt):
     return m.get(metaopt)
 
 
-def display(metaopts, burl, prefix=False):
+def display(metaopts, burl, prefix=False, tagvalue=''):
     """primitive: display metaopts (list) values with optional prefix"""
 
-    m = EC2Metadata(burl)
+    m = EC2Metadata(burl, tagvalue)
     for metaopt in metaopts:
         value = m.get(metaopt)
         if not value:
@@ -253,11 +281,13 @@ def main():
         getopt_metaopts = METAOPTS[:]
         getopt_metaopts.append('help')
         getopt_metaopts.append('url=')
+        getopt_metaopts.append('tag=')
         opts, _ = getopt.gnu_getopt(sys.argv[1:], "hu:", getopt_metaopts)
     except getopt.GetoptError as e:
         usage(e)
 
     burl = instdata_url
+    tagvalue = ''
 
     metaopts = []
     prefix = False
@@ -267,17 +297,19 @@ def main():
         if opt in ('-u', '--url'):
             burl = val
             continue
+        if opt in ('-t', '--tag'):
+            tagvalue = val
 
         metaopts.append(opt.replace('--', ''))
 
     if len(metaopts) == 0:
         prefix = True
         metaopts = METAOPTS
 
-    display(metaopts, burl, prefix)
+    display(metaopts, burl, prefix, tagvalue)
 
 
 if __name__ == "__main__":
     main()
 
-# vi: ts=4 expandtab
+# vi: ts=4 expandtab