Base utils for xsd mi validation and saved sessions file

[deliverable/lttng-ivc.git] / lttng_ivc / utils / utils.py

diff --git a/lttng_ivc/utils/utils.py b/lttng_ivc/utils/utils.py
index 23ce4bce20ae3d2700d0bb57ace4d1cf5cbb7dcb..1660aba1383469d0f6d289aeab431dc87ceedea0 100644 (file)
--- a/lttng_ivc/utils/utils.py
+++ b/lttng_ivc/utils/utils.py
@@ -1,5 +1,12 @@
 import signal
 import hashlib
+import os
+import time
+import socket
+
+from lxml import etree
+from contextlib import closing
+
 
 def line_count(file_path):
     line_count = 0
@@ -17,13 +24,106 @@ def sha256_checksum(filename, block_size=65536):
     return sha256.hexdigest()
 
 
+# TODO: timeout as a parameter or Settings
+# TODO: Custom exception
+def wait_for_file(path):
+    i = 0
+    timeout = 60
+    while not os.path.exists(path):
+        time.sleep(1)
+        i = i + 1
+        if i > timeout:
+            raise Exception("File still does not exists. Timeout expired")
+
+
+# TODO: find better exception
+def create_empty_file(path):
+    if os.path.exists(path):
+        raise Exception("Path already exist")
+    open(path, 'w').close()
+
+
 def __dummy_sigusr1_handler():
     pass
 
 
 def sessiond_spawn(runtime):
-        previous_handler = signal.signal(signal.SIGUSR1, __dummy_sigusr1_handler)
-        sessiond = runtime.spawn_subprocess("lttng-sessiond -vvv -S")
-        signal.sigtimedwait({signal.SIGUSR1}, 60)
-        previous_handler = signal.signal(signal.SIGUSR1, previous_handler)
-        return sessiond
+    agent_port = find_free_port()
+    previous_handler = signal.signal(signal.SIGUSR1, __dummy_sigusr1_handler)
+    sessiond = runtime.spawn_subprocess("lttng-sessiond -vvv -S --agent-tcp-port {}".format(agent_port))
+    signal.sigtimedwait({signal.SIGUSR1}, 60)
+    previous_handler = signal.signal(signal.SIGUSR1, previous_handler)
+    return sessiond
+
+
+def find_free_port():
+    # There is no guarantee that the port will be free at runtime but should be
+    # good enough
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as s:
+        s.bind(('', 0))
+        return s.getsockname()[1]
+
+
+def file_contains(file_path, list_of_string):
+    with open(file_path, 'r') as f:
+        for line in f:
+            for s in list_of_string:
+                if s in line:
+                    return True
+
+
+def find_dir(root, name):
+    """
+    Returns the absolute path or None.
+    """
+    abs_path = None
+    for base, dirs, files in os.walk(root):
+        for tmp in dirs:
+            if tmp.endswith(name):
+                abs_path = os.path.abspath(os.path.join(base, tmp))
+    return abs_path
+
+
+def find_file(root, name):
+    """
+    Returns the absolute path or None.
+    """
+    print(root)
+    print(name)
+    abs_path = None
+    for base, dirs, files in os.walk(root):
+        for tmp in files:
+            if tmp.endswith(name):
+                abs_path = os.path.abspath(os.path.join(base, tmp))
+    print(abs_path)
+    return abs_path
+
+
+def validate(xml_path, xsd_path):
+
+    xmlschema_doc = etree.parse(xsd_path)
+    xmlschema = etree.XMLSchema(xmlschema_doc)
+
+    xml_doc = etree.parse(xml_path)
+    result = xmlschema.validate(xml_doc)
+
+    return result
+
+def xpath_query(xml_file, xpath):
+    """
+    Return a list of xml node corresponding to the xpath. The list can be of lenght
+    zero.
+    """
+    with open(xml_file, 'r') as f:
+        tree = etree.parse(f)
+        root = tree.getroot()
+        # Remove all namespace
+        # https://stackoverflow.com/questions/18159221/remove-namespace-and-prefix-from-xml-in-python-using-lxml
+        for elem in root.getiterator():
+            if not hasattr(elem.tag, 'find'):
+                continue
+            i = elem.tag.find('}')
+            if i >= 0:
+                elem.tag = elem.tag[i+1:]
+
+        return root.xpath(xpath)