qa/tasks: use next(iter(..)) for accessing first element in a view

in python2, dict.values() and dict.keys() return lists. but in python3,
they return views, which cannot be indexed directly using an integer index.

there are three use cases when we access these views in python3:

1. get the first element
2. get all the elements and then *might* want to access them by index
3. get the first element assuming there is only a single element in
   the view
4. iterate thru the view

in the 1st case, we cannot assume the number of elements, so to be
python3 compatible, we should use `next(iter(a_dict))` instead.

in the 2nd case, in this change, the view is materialized using
`list(a_dict)`.

in the 3rd case, we can just continue using the short hand of
```py
(first_element,) = a_dict.keys()
```
to unpack the view. this works in both python2 and python3.

in the 4th case, the existing code works in both python2 and python3, as
both list and view can be iterated using `iter`, and `len` works as
well.

Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit d7258ea7fdcd81d4a88028a25b32ed5b278d0752)

diff --git a/qa/tasks/barbican.py b/qa/tasks/barbican.py
index 0ce4aefb7d0b04809d20c248d58dc38f30d13632..e191476c4329395e2e54de9ecb538416a72fc627 100644 (file)
--- a/qa/tasks/barbican.py
+++ b/qa/tasks/barbican.py
@@ -172,7 +172,7 @@ def configure_barbican(ctx, config):
     Configure barbican paste-api and barbican-api.
     """
     assert isinstance(config, dict)
-    (cclient, cconfig) = config.items()[0]
+    (cclient, cconfig) = next(iter(config.items()))
 
     keystone_role = cconfig.get('use-keystone-role', None)
     if keystone_role is None:
@@ -239,7 +239,7 @@ def create_secrets(ctx, config):
     Create a main and an alternate s3 user.
     """
     assert isinstance(config, dict)
-    (cclient, cconfig) = config.items()[0]
+    (cclient, cconfig) = next(iter(config.items()))
 
     rgw_user = cconfig['rgw_user']
 

diff --git a/qa/tasks/cbt.py b/qa/tasks/cbt.py
index c5567a05d020efa6f8f9dcc7d8c97172602c3616..3255107add602b87a6ff220fe6bbde76db9e483e 100644 (file)
--- a/qa/tasks/cbt.py
+++ b/qa/tasks/cbt.py
@@ -44,7 +44,7 @@ class CBT(Task):
             )
 
         benchmark_config = self.config.get('benchmarks')
-        benchmark_type = benchmark_config.keys()[0]
+        benchmark_type = next(iter(benchmark_config.keys()))
         if benchmark_type in ['librbdfio', 'fio']:
           testdir = misc.get_testdir(self.ctx)
           benchmark_config[benchmark_type]['cmd_path'] = os.path.join(testdir, 'fio/fio')
@@ -80,7 +80,7 @@ class CBT(Task):
             cbt_depends = ['python3-yaml', 'python3-lxml', 'librbd-dev', 'collectl']
         self.first_mon.run(args=install_cmd + cbt_depends)
 
-        benchmark_type = self.cbt_config.get('benchmarks').keys()[0]
+        benchmark_type = next(iter(self.cbt_config.get('benchmarks').keys()))
         self.log.info('benchmark: %s', benchmark_type)
 
         if benchmark_type in ['librbdfio', 'fio']:
@@ -201,7 +201,7 @@ class CBT(Task):
 
     def setup(self):
         super(CBT, self).setup()
-        self.first_mon = self.ctx.cluster.only(misc.get_first_mon(self.ctx, self.config)).remotes.keys()[0]
+        self.first_mon = next(iter(self.ctx.cluster.only(misc.get_first_mon(self.ctx, self.config)).remotes.keys()))
         self.cbt_config = self.generate_cbt_config()
         self.log.info('cbt configuration is %s', self.cbt_config)
         self.cbt_dir = os.path.join(misc.get_archive_dir(self.ctx), 'cbt')
@@ -233,7 +233,7 @@ class CBT(Task):
                 '{tdir}/cbt'.format(tdir=testdir),
             ]
         )
-        benchmark_type = self.cbt_config.get('benchmarks').keys()[0]
+        benchmark_type = next(iter(self.cbt_config.get('benchmarks').keys()))
         if benchmark_type in ['librbdfio', 'fio']:
             self.first_mon.run(
                 args=[

diff --git a/qa/tasks/ceph_manager.py b/qa/tasks/ceph_manager.py
index 42b437355868297f4b0ca73f51282b2febec2c32..39d2b0bc91955a8172b5c5984ea41dfd425328a3 100644 (file)
--- a/qa/tasks/ceph_manager.py
+++ b/qa/tasks/ceph_manager.py
@@ -1239,8 +1239,8 @@ class ObjectStoreTool:
             self.pgid = self.manager.get_object_pg_with_shard(self.pool,
                                                               self.object_name,
                                                               self.osd)
-        self.remote = self.manager.ctx.\
-            cluster.only('osd.{o}'.format(o=self.osd)).remotes.keys()[0]
+        self.remote = next(iter(self.manager.ctx.\
+            cluster.only('osd.{o}'.format(o=self.osd)).remotes.keys()))
         path = self.manager.get_filepath().format(id=self.osd)
         self.paths = ("--data-path {path} --journal-path {path}/journal".
                       format(path=path))

diff --git a/qa/tasks/ceph_objectstore_tool.py b/qa/tasks/ceph_objectstore_tool.py
index 8636fdb6f3f035e1bac0ae5f5753eebb26d8630a..602cc85991b7ac21ee5d0b51f72b25f8967fd414 100644 (file)
--- a/qa/tasks/ceph_objectstore_tool.py
+++ b/qa/tasks/ceph_objectstore_tool.py
@@ -240,7 +240,7 @@ def test_objectstore(ctx, config, cli_remote, REP_POOL, REP_NAME, ec=False):
                          REP_NAME, DATALINECOUNT)
     allremote = []
     allremote.append(cli_remote)
-    allremote += osds.remotes.keys()
+    allremote += list(osds.remotes.keys())
     allremote = list(set(allremote))
     for remote in allremote:
         cod_setup_remote_data(log, ctx, remote, NUM_OBJECTS, DATADIR,

diff --git a/qa/tasks/cephfs/filesystem.py b/qa/tasks/cephfs/filesystem.py
index 093bb73efc0a7aee74a4c5ee83730a999e94dfd7..71c9a2ae6ab1422f8fa54bc041ee0023934d6df8 100644 (file)
--- a/qa/tasks/cephfs/filesystem.py
+++ b/qa/tasks/cephfs/filesystem.py
@@ -691,7 +691,7 @@ class Filesystem(MDSCluster):
         if refresh or self.data_pools is None:
             self.get_pool_names(refresh = True)
         assert(len(self.data_pools) == 1)
-        return self.data_pools.values()[0]
+        return next(iter(self.data_pools.values()))
 
     def get_data_pool_id(self, refresh = False):
         """
@@ -701,12 +701,12 @@ class Filesystem(MDSCluster):
         if refresh or self.data_pools is None:
             self.get_pool_names(refresh = True)
         assert(len(self.data_pools) == 1)
-        return self.data_pools.keys()[0]
+        return next(iter(self.data_pools.keys()))
 
     def get_data_pool_names(self, refresh = False):
         if refresh or self.data_pools is None:
             self.get_pool_names(refresh = True)
-        return self.data_pools.values()
+        return list(self.data_pools.values())
 
     def get_metadata_pool_name(self):
         return self.metadata_pool_name

diff --git a/qa/tasks/check_counter.py b/qa/tasks/check_counter.py
index fc877f285b6c8174204ef23f2c4b084f2f7e22f5..daa81973be7358256646eb8dddcdb1b8251ca2f9 100644 (file)
--- a/qa/tasks/check_counter.py
+++ b/qa/tasks/check_counter.py
@@ -45,7 +45,7 @@ class CheckCounter(Task):
         targets = self.config.get('counters', {})
 
         if cluster_name is None:
-            cluster_name = self.ctx.managers.keys()[0]
+            cluster_name = next(iter(self.ctx.managers.keys()))
 
         for daemon_type, counters in targets.items():
             # List of 'a', 'b', 'c'...

diff --git a/qa/tasks/devstack.py b/qa/tasks/devstack.py
index 943a9ffffa22465577ace8ab19c54e3468b7ac16..ba3d29aab539b3ab03d5242244fc4e35d5353687 100644 (file)
--- a/qa/tasks/devstack.py
+++ b/qa/tasks/devstack.py
@@ -58,8 +58,8 @@ def install(ctx, config):
     if not isinstance(config, dict):
         raise TypeError("config must be a dict")
 
-    devstack_node = ctx.cluster.only(is_devstack_node).remotes.keys()[0]
-    an_osd_node = ctx.cluster.only(is_osd_node).remotes.keys()[0]
+    devstack_node = next(iter(ctx.cluster.only(is_devstack_node).remotes.keys()))
+    an_osd_node = next(iter(ctx.cluster.only(is_osd_node).remotes.keys()))
 
     devstack_branch = config.get("branch", "master")
     install_devstack(devstack_node, devstack_branch)
@@ -305,7 +305,7 @@ def exercise(ctx, config):
     if not isinstance(config, dict):
         raise TypeError("config must be a dict")
 
-    devstack_node = ctx.cluster.only(is_devstack_node).remotes.keys()[0]
+    devstack_node = next(iter(ctx.cluster.only(is_devstack_node).remotes.keys()))
 
     # TODO: save the log *and* preserve failures
     #devstack_archive_dir = create_devstack_archive(ctx, devstack_node)
@@ -332,8 +332,8 @@ def create_devstack_archive(ctx, devstack_node):
 def smoke(ctx, config):
     log.info("Running a basic smoketest...")
 
-    devstack_node = ctx.cluster.only(is_devstack_node).remotes.keys()[0]
-    an_osd_node = ctx.cluster.only(is_osd_node).remotes.keys()[0]
+    devstack_node = next(iter(ctx.cluster.only(is_devstack_node).remotes.keys()))
+    an_osd_node = next(iter(ctx.cluster.only(is_osd_node).remotes.keys()))
 
     try:
         create_volume(devstack_node, an_osd_node, 'smoke0', 1)

diff --git a/qa/tasks/dnsmasq.py b/qa/tasks/dnsmasq.py
index 2bf3feaf083714e490c58f5e6ccca15f168c823d..ad2772a641ff26c60d832b9c38b42c0e21575aa7 100644 (file)
--- a/qa/tasks/dnsmasq.py
+++ b/qa/tasks/dnsmasq.py
@@ -83,7 +83,7 @@ def setup_dnsmasq(remote, testdir, cnames):
     # restart dnsmasq
     remote.run(args=['sudo', 'systemctl', 'restart', 'dnsmasq'])
     # verify dns name is set
-    remote.run(args=['ping', '-c', '4', cnames.keys()[0]])
+    remote.run(args=['ping', '-c', '4', next(iter(cnames.keys()))])
 
     try:
         yield

diff --git a/qa/tasks/filestore_idempotent.py b/qa/tasks/filestore_idempotent.py
index 01b562905b212408f09d89060a689e875035cdfc..319bef7686c71d8ad0a25b62a6607411a1ff354c 100644 (file)
--- a/qa/tasks/filestore_idempotent.py
+++ b/qa/tasks/filestore_idempotent.py
@@ -31,7 +31,7 @@ def task(ctx, config):
     clients = config.keys()
 
     # just use the first client...
-    client = clients[0];
+    client = next(iter(clients))
     (remote,) = ctx.cluster.only(client).remotes.keys()
 
     testdir = teuthology.get_testdir(ctx)

diff --git a/qa/tasks/mgr/test_crash.py b/qa/tasks/mgr/test_crash.py
index 149221e9f6075403e77b24359019d3cff99ac7fa..cb67975be4d25379f4cfa363602131f863612db4 100644 (file)
--- a/qa/tasks/mgr/test_crash.py
+++ b/qa/tasks/mgr/test_crash.py
@@ -74,7 +74,7 @@ class TestCrash(MgrTestCase):
             self.assertIn(crash['crash_id'], retstr)
 
     def test_rm(self):
-        crashid = self.crashes.keys()[0]
+        crashid = next(iter(self.crashes.keys()))
         self.assertEqual(
             0,
             self.mgr_cluster.mon_manager.raw_cluster_cmd_result(

diff --git a/qa/tasks/radosgw_admin.py b/qa/tasks/radosgw_admin.py
index e1348a21cf3fb6d1fcead6787f9fe19b6fa592e1..c7ef3ad87f2524c87bd2e1e9ea2c8e002449d2a1 100644 (file)
--- a/qa/tasks/radosgw_admin.py
+++ b/qa/tasks/radosgw_admin.py
@@ -271,7 +271,7 @@ def task(ctx, config):
     clients_from_config = config.keys()
 
     # choose first client as default
-    client = clients_from_config[0]
+    client = next(iter(clients_from_config))
 
     # once the client is chosen, pull the host name and  assigned port out of
     # the role_endpoints that were assigned by the rgw task

diff --git a/qa/tasks/radosgw_admin_rest.py b/qa/tasks/radosgw_admin_rest.py
index 50f88ea85700890f025a9c5e71a7c204b11840f1..ae47bec4929a285d52fbfd3e8a59ce5bfb2758bf 100644 (file)
--- a/qa/tasks/radosgw_admin_rest.py
+++ b/qa/tasks/radosgw_admin_rest.py
@@ -130,7 +130,7 @@ def task(ctx, config):
     clients = config.keys()
 
     # just use the first client...
-    client = clients[0]
+    client = next(iter(clients))
 
     ##
     admin_user = 'ada'

diff --git a/qa/tasks/vault.py b/qa/tasks/vault.py
index 34efc4f970c61bbfaee492962b041da1a62ee462..1265513408bc1caef5d71e818f2ca12079920b88 100644 (file)
--- a/qa/tasks/vault.py
+++ b/qa/tasks/vault.py
@@ -128,7 +128,7 @@ def setup_vault(ctx, config):
     """
     Mount Transit or KV version 2 secrets engine
     """
-    (cclient, cconfig) = config.items()[0]
+    (cclient, cconfig) = next(iter(config.items()))
     engine = cconfig.get('engine')
 
     if engine == 'kv':
@@ -169,7 +169,7 @@ def send_req(ctx, cconfig, client, path, body, method='POST'):
 
 @contextlib.contextmanager
 def create_secrets(ctx, config):
-    (cclient, cconfig) = config.items()[0]
+    (cclient, cconfig) = next(iter(config.items()))
     engine = cconfig.get('engine')
     prefix = cconfig.get('prefix')
     secrets = cconfig.get('secrets')