5 files changed, 92 insertions, 0 deletions
diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index ea649cc2..1cf98ef5 100755
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -364,4 +364,9 @@ def get_interfaces_by_mac(devs=None):
             ret[mac] = name
     return ret
 
+
+class RendererNotFoundError(RuntimeError):
+    pass
+
+
 # vi: ts=4 expandtab
diff --git a/cloudinit/net/eni.py b/cloudinit/net/eni.py
index efa034bf..9d39a2b0 100644
--- a/cloudinit/net/eni.py
+++ b/cloudinit/net/eni.py
@@ -500,4 +500,18 @@ def network_state_to_eni(network_state, header=None, render_hwaddress=False):
         network_state, render_hwaddress=render_hwaddress)
     return header + contents
 
+
+def available(target=None):
+    expected = ['ifquery', 'ifup', 'ifdown']
+    search = ['/sbin', '/usr/sbin']
+    for p in expected:
+        if not util.which(p, search=search, target=target):
+            return False
+    eni = util.target_path(target, 'etc/network/interfaces')
+    if not os.path.is_file(eni):
+        return False
+
+    return True
+
+
 # vi: ts=4 expandtab
diff --git a/cloudinit/net/renderer.py b/cloudinit/net/renderer.py
index 3a192436..a5b2b573 100644
--- a/cloudinit/net/renderer.py
+++ b/cloudinit/net/renderer.py
@@ -7,6 +7,7 @@
 
 import six
 
+from .network_state import parse_net_config_data
 from .udev import generate_udev_rule
 
 
@@ -36,4 +37,8 @@ class Renderer(object):
                                                  iface['mac_address']))
         return content.getvalue()
 
+    def render_network_config(self, network_config, target=None):
+        return self.render_network_state(
+            network_state=parse_net_config_data(network_config), target=target)
+
 # vi: ts=4 expandtab
diff --git a/cloudinit/net/renderers.py b/cloudinit/net/renderers.py
new file mode 100644
index 00000000..5ad84553
--- /dev/null
+++ b/cloudinit/net/renderers.py
@@ -0,0 +1,51 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+
+from . import eni
+from . import RendererNotFoundError
+from . import sysconfig
+
+NAME_TO_RENDERER = {
+    "eni": eni,
+    "sysconfig": sysconfig,
+}
+
+DEFAULT_PRIORITY = ["eni", "sysconfig"]
+
+
+def search(priority=None, target=None, first=False):
+    if priority is None:
+        priority = DEFAULT_PRIORITY
+
+    available = NAME_TO_RENDERER
+
+    unknown = [i for i in priority if i not in available]
+    if unknown:
+        raise ValueError(
+            "Unknown renderers provided in priority list: %s" % unknown)
+
+    found = []
+    for name in priority:
+        render_mod = available[name]
+        if render_mod.available(target):
+            cur = (name, render_mod.Renderer)
+            if first:
+                return cur
+            found.append(cur)
+
+    return found
+
+
+def select(priority=None, target=None):
+    found = search(priority, target=target, first=True)
+    if not found:
+        if priority is None:
+            priority = DEFAULT_PRIORITY
+        tmsg = ""
+        if target and target != "/":
+            tmsg = " in target=%s" % target
+        raise RendererNotFoundError(
+            "No available network renderers found%s. Searched "
+            "through list: %s" % (tmsg, priority))
+    return found
+
+# vi: ts=4 expandtab
diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
index 4eeaaa8a..117b515c 100644
--- a/cloudinit/net/sysconfig.py
+++ b/cloudinit/net/sysconfig.py
@@ -404,4 +404,21 @@ class Renderer(renderer.Renderer):
             netrules_path = util.target_path(target, self.netrules_path)
             util.write_file(netrules_path, netrules_content)
 
+
+def available(target=None):
+    expected = ['ifup', 'ifdown']
+    search = ['/sbin', '/usr/sbin']
+    for p in expected:
+        if not util.which(p, search=search, target=target):
+            return False
+
+    expected_paths = [
+        'etc/sysconfig/network-scripts/network-functions',
+        'etc/sysconfig/network-scripts/ifdown-eth']
+    for p in expected_paths:
+        if not os.path.isfile(util.target_path(target, p)):
+            return False
+    return True
+
+
 # vi: ts=4 expandtab