Initial preparation for two-phase conversion

Signed-off-by: Martin Kletzander <[email protected]>

Author: nertpinx

docs/Virt-v2v-wrapper.md

@@ -9,14 +9,18 @@ The expected usage is as follows:
 
 1)  *wrapper start*: client runs the wrapper; at the moment there are no
     command line arguments and everything is configured by JSON data presented
-    on stdin.
+    on stdin
 
 2)  *initialization*: wrapper read JSON data from stdin, parses and validates
     the content; based on the situation it may also change the effective user
     to a non-root account; wrapper writes to stdout simple JSON containing
     paths to wrapper log file (`wrapper_log`), virt-v2v log file (`v2v_log`),
     state file (`state_file`) that can be used to monitor the progress
 
+3)  Optionally, if `two_phase` conversion is selected (not supported for all
+    input and output modes), it will copy the disks to their destinations and
+    generate a libvirt XML to be used as an input to the virt-v2v process
+
 4)  *conversion*: finally, virt-v2v process is executed; wrapper monitors its
     output and updates the state file on a regular basis
 
@@ -55,6 +59,12 @@ following can be specified:
 * `ssh_key`: optional, private part of SSH key to use. If this is not provided
   then keys in ~/.ssh directory are used.
 
+Two-phase conversion can be requested by setting `two_phase` to `True` at which
+point the following key is mandatory:
+
+* `conversion_host_uuid`: the UUID of a VM in which the actual conversion is
+  being performed.
+
 Output configuration: reffer to the section [Output
 configuration](#output-configuration) below.
 
@@ -144,6 +154,11 @@ Example:
 State file is a JSON file. Its content changes as the conversion goes through
 various stages. With it also the keys present in the file.
 
+If two-phase conversion is selected there will be a key `pre_copy` with various
+information related to the first (pre-copy) phase of the conversion.  The
+particular keys and information is, at the time of this writing, subject to
+change, but whould be as self-explanatory as possible.
+
 Once virt-v2v is executed the state file is created with the following keys:
 
 * `started`: with value `true`

wrapper/hosts.py

@@ -77,6 +77,12 @@ def validate_data(self, data):
         """ Validate input data, fill in defaults, etc """
         hard_error("Cannot validate data for unknown host type")
 
+    def prepare_disks(self, data):
+        """ Validate input data, fill in defaults, etc """
+        if data['two_phase']:
+            hard_error("Host implementation did not forbid two phase "
+                       "conversion, but did not implement `prepare_disks`")
+
 
 class KubevirtHost(_BaseHost):
 
@@ -152,7 +158,11 @@ def update_progress(self):
 
     def validate_data(self, data):
         """ Validate input data, fill in defaults, etc """
-        pass
+        if data['two_phase']:
+            # If adding support for two-phase conversion, do not forget to fix
+            # the update_progress() method
+            hard_error('Two-phase conversion is not supported for '
+                       'Kubevirt host')
 
 
 class _K8SCommunicator(object):
@@ -482,6 +492,9 @@ def validate_data(self, data):
         for mapping in data['network_mappings']:
             if 'mac_address' not in mapping:
                 hard_error('Missing mac address in one of network mappings')
+        if data['two_phase']:
+            hard_error('Two-phase conversion is not supported for '
+                       'Openstack host')
         return data
 
     def _check_ip_in_network(self, ipaddr, network):
@@ -707,6 +720,10 @@ def validate_data(self, data):
         else:
             hard_error('No target specified')
 
+        if data['two_phase']:
+            hard_error('Two-phase conversion is not supported for '
+                       'Ovirt host')
+
         if 'rhv_url' in data:
             with self.sdk_connection(data) as c:
                 vm_svc = c.system_service().vms_service()