Library functions to run commands in ocp pods

This version cleans up various aspects of the code wrt review
comments as well as trying to make it a bit more pythonic

Change-Id: Ic0ada62b3ba8ce1ebc471d358daedea4572c3b0d
Signed-off-by: Arthy Loganathan <aloganat@redhat.com>
Signed-off-by: John Mulligan <jmulligan@redhat.com>

2 files changed, 210 insertions, 0 deletions

diff --git a/cns-libs/cnslibs/common/openshift_ops.py b/cns-libs/cnslibs/common/openshift_ops.py
new file mode 100644
index 00000000..beff3272
--- /dev/null
+++ b/cns-libs/cnslibs/common/openshift_ops.py
@@ -0,0 +1,166 @@
+"""Library for openshift operations.
+
+Various utility functions for interacting with OCP/OpenShift.
+"""
+
+import re
+import types
+
+import yaml
+
+from glusto.core import Glusto as g
+
+
+PODS_WIDE_RE = re.compile(
+    '(\S+)\s+(\S+)\s+(\w+)\s+(\d+)\s+(\S+)\s+(\S+)\s+(\S+)\n')
+
+
+def oc_get_pods(ocp_node):
+    """Gets the pods info with 'wide' option in the current project.
+
+    Args:
+        ocp_node (str): Node in which ocp command will be executed.
+
+    Returns:
+        dict : dict of pods info in the current project.
+    """
+
+    cmd = "oc get -o wide --no-headers=true pods"
+    ret, out, err = g.run(ocp_node, cmd)
+    if ret != 0:
+        g.log.error("Failed to get ocp pods on node %s" % ocp_node)
+        raise AssertionError('failed to get pods: %r' % (err,))
+    return _parse_wide_pods_output(out)
+
+
+def _parse_wide_pods_output(output):
+    """Parse the output of `oc get -o wide pods`.
+    """
+    # Interestingly, the output of get pods is "cooked" in such a way that
+    # the values in the ready, status, & restart fields are not accessible
+    # from YAML/JSON/templating forcing us to scrape the output for
+    # these values
+    # (at the time of this writing the logic is in
+    #  printPodBase in kubernetes/pkg/printers/internalversion/printers.go )
+    # Possibly obvious, but if you don't need those values you can
+    # use the YAML output directly.
+    #
+    # TODO: Add unit tests for this parser
+    pods_info = {}
+    for each_pod_info in PODS_WIDE_RE.findall(output):
+        pods_info[each_pod_info[0]] = {
+            'ready': each_pod_info[1],
+            'status': each_pod_info[2],
+            'restarts': each_pod_info[3],
+            'age': each_pod_info[4],
+            'ip': each_pod_info[5],
+            'node': each_pod_info[6],
+        }
+    return pods_info
+
+
+def oc_get_pods_full(ocp_node):
+    """Gets all the pod info via YAML in the current project.
+
+    Args:
+        ocp_node (str): Node in which ocp command will be executed.
+
+    Returns:
+        dict: The YAML output converted to python objects
+            (a top-level dict)
+    """
+
+    cmd = "oc get -o yaml pods"
+    ret, out, err = g.run(ocp_node, cmd)
+    if ret != 0:
+        g.log.error("Failed to get ocp pods on node %s" % ocp_node)
+        raise AssertionError('failed to get pods: %r' % (err,))
+    return yaml.load(out)
+
+
+def get_ocp_gluster_pod_names(ocp_node):
+    """Gets the gluster pod names in the current project.
+
+    Args:
+        ocp_node (str): Node in which ocp command will be executed.
+
+    Returns:
+        list : list of gluster pod names in the current project.
+            Empty list, if there are no gluster pods.
+
+    Example:
+        get_ocp_gluster_pod_names(ocp_node)
+    """
+
+    pod_names = oc_get_pods(ocp_node).keys()
+    return [pod for pod in pod_names if pod.startswith('glusterfs-')]
+
+
+def oc_login(ocp_node, username, password):
+    """Login to ocp master node.
+
+    Args:
+        ocp_node (str): Node in which ocp command will be executed.
+        username (str): username of ocp master node to login.
+        password (str): password of ocp master node to login.
+
+    Returns:
+        bool : True on successful login to ocp master node.
+            False otherwise
+
+    Example:
+        oc_login(ocp_node, "test","test")
+    """
+
+    cmd = "oc login --username=%s --password=%s" % (username, password)
+    ret, _, _ = g.run(ocp_node, cmd)
+    if ret != 0:
+        g.log.error("Failed to login to ocp master node %s" % ocp_node)
+        return False
+    return True
+
+
+def switch_oc_project(ocp_node, project_name):
+    """Switch to the given project.
+
+    Args:
+        ocp_node (str): Node in which ocp command will be executed.
+        project_name (str): Project name.
+    Returns:
+        bool : True on switching to given project.
+            False otherwise
+
+    Example:
+        switch_oc_project(ocp_node, "storage-project")
+    """
+
+    cmd = "oc project %s" % project_name
+    ret, _, _ = g.run(ocp_node, cmd)
+    if ret != 0:
+        g.log.error("Failed to switch to project %s" % project_name)
+        return False
+    return True
+
+
+def oc_rsh(ocp_node, pod_name, command):
+    """Run a command in the ocp pod using `oc rsh`.
+
+    Args:
+        ocp_node (str): Node on which oc rsh command will be executed.
+        pod_name (str): Name of the pod on which the command will
+            be executed.
+        command (str|list): command to run.
+
+    Returns:
+        A tuple consisting of the command return code, stdout, and stderr.
+    """
+    prefix = ['oc', 'rsh', pod_name]
+    if isinstance(command, types.StringTypes):
+        cmd = ' '.join(prefix + [command])
+    else:
+        cmd = prefix + command
+
+    # unpack the tuple to make sure our return value exactly matches
+    # our docstring
+    ret, stdout, stderr = g.run(ocp_node, cmd)
+    return (ret, stdout, stderr)
diff --git a/cns-libs/cnslibs/common/utils.py b/cns-libs/cnslibs/common/utils.py
new file mode 100644
index 00000000..a47ccafa
--- /dev/null
+++ b/cns-libs/cnslibs/common/utils.py
@@ -0,0 +1,44 @@
+"""Generic host utility functions.
+
+Generic utility functions not specifc to a larger suite of tools.
+For example, not specific to OCP, Gluster, Heketi, etc.
+"""
+
+import re
+
+from glusto.core import Glusto as g
+
+
+ONE_GB_BYTES = 1073741824.0
+
+
+def get_device_size(host, device_name):
+    """Gets device size for the given device name.
+
+    Args:
+        host (str): Node in command will be executed.
+        device_name (str): device name for which the size has to
+            be calculated.
+
+    Returns:
+        str : returns device size in GB on success
+            False otherwise
+
+    Example:
+        get_device_size(host, device_name)
+    """
+
+    cmd = "fdisk -l %s " % device_name
+    ret, out, _ = g.run(host, cmd)
+    if ret != 0:
+        g.log.error("Failed to execute fdisk -l command "
+                    "on node %s" % host)
+        return False
+
+    regex = 'Disk\s' + device_name + '.*?,\s(\d+)\sbytes\,.*'
+    match = re.search(regex, out)
+    if match is None:
+        g.log.error("Regex mismatch while parsing fdisk -l output")
+        return False
+
+    return str(int(int(match.group(1))/ONE_GB_BYTES))