Cleaner implementation of the variable cache
* Separate implementation that acts as a MutableMapping * I'm still not sure about this. Also, there is a design error in there, because it's not possible to "return" a value from a block unless it's written to a fact.
This commit is contained in:
parent
b79e9f8faf
commit
46e675dedb
1 changed files with 96 additions and 72 deletions
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@ -1,4 +1,5 @@
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import abc
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from collections import MutableMapping
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from ansible import constants as C
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from ansible.errors import AnsibleParserError, AnsibleRuntimeError, AnsibleError
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@ -107,6 +108,55 @@ INSTR_FIELDS = {k: set(v + INSTR_COMMON_FIELDS) for k, v in INSTR_OWN_FIELDS.ite
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"""All supported fields for each instruction, including common and specific fields."""
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class VariableStorage(MutableMapping):
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def __init__(self, host_vars):
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self._host_vars = host_vars
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self._script_stack = [{}]
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self._cache = host_vars.copy()
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def _script_stack_push(self):
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self._script_stack.append(self._script_stack[-1].copy())
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def _script_stack_pop(self):
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self._script_stack.pop()
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self._cache = self._host_vars.copy()
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self._cache.update(self._script_stack[-1])
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def _set_host_var(self, name, value):
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self._host_vars[name] = value
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if name not in self._script_stack[-1]:
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self._cache[name] = value
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def __getitem__(self, k):
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return self._cache[k]
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def __setitem__(self, k, v):
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self._script_stack[-1][k] = v
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self._cache[k] = v
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def __delitem__(self, k):
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del self._script_stack[-1][k]
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if k in self._host_vars:
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self._cache[k] = self._host_vars[k]
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else:
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del self._cache[k]
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def __iter__(self):
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return self._cache.__iter__()
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def __len__(self):
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return len(self._cache)
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def keys(self):
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return self._cache.keys()
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def items(self):
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return self._cache.items()
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def values(self):
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return self._cache.values()
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class RcInstruction(abc.ABC):
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"""An instruction that can be executed by the plugin."""
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@ -269,7 +319,7 @@ class RcInstruction(abc.ABC):
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"""
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raise NotImplementedError
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def run_for(self, host_name, merged_vars, host_vars, script_vars):
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def run_for(self, host_name, variables):
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"""Execute the instruction for a given host.
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This method is the entry point for instruction execution. Depending on
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@ -279,10 +329,7 @@ class RcInstruction(abc.ABC):
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Args:
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host_name: the name of the host to execute the instruction for
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merged_vars: the variable cache, with local script variables \
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taking precedence over host facts.
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host_vars: the host's facts, as a mapping
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script_vars: the current script variables, as a mapping
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variables: the variable storage instance
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Returns:
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``True`` if execution must continue, ``False`` if it must be
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@ -290,51 +337,42 @@ class RcInstruction(abc.ABC):
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"""
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if self._loop is None:
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self._display.vvvv("%s : running action %s" % (host_name, self._action))
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return self.run_once(host_name, merged_vars, host_vars, script_vars)
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return self.run_once(host_name, variables)
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# Save previous loop variable state
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had_loop_var = self._loop_var in script_vars
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had_loop_var = self._loop_var in variables
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if had_loop_var:
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old_loop_var = script_vars[self._loop_var]
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old_loop_var = variables[self._loop_var]
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try:
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# Loop over all values
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for value in self.evaluate_loop(host_name, merged_vars):
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for value in self.evaluate_loop(host_name, variables):
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self._display.vvvv(
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"%s : running action %s for item %s"
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% (host_name, self._action, repr(value))
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)
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merged_vars[self._loop_var] = value
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script_vars[self._loop_var] = value
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if not self.run_once(host_name, merged_vars, host_vars, script_vars):
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variables[self._loop_var] = value
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if not self.run_once(host_name, variables):
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return False
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return True
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finally:
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# Restore loop variable state
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if had_loop_var:
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script_vars[self._loop_var] = old_loop_var
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merged_vars[self._loop_var] = old_loop_var
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variables[self._loop_var] = old_loop_var
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else:
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del script_vars[self._loop_var]
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if self._loop_var in host_vars:
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merged_vars[self._loop_var] = host_vars[self._loop_var]
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else:
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del merged_vars[self._loop_var]
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del variables[self._loop_var]
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def run_once(self, host_name, merged_vars, host_vars, script_vars):
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def run_once(self, host_name, variables):
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"""Check the condition if it exists, then run the instruction.
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Args:
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host_name: the name of the host to execute the instruction for
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merged_vars: the variable cache, with local script variables \
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taking precedence over host facts.
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host_vars: the host's facts, as a mapping
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script_vars: the current script variables, as a mapping
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variables: the variable storage instance
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Returns:
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``True`` if execution must continue, ``False`` if it must be
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interrupted
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"""
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if self.evaluate_condition(host_name, merged_vars):
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rv = self.execute_action(host_name, merged_vars, host_vars, script_vars)
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if self.evaluate_condition(host_name, variables):
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rv = self.execute_action(host_name, variables)
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if not rv:
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self._display.vvvvv(
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"%s : action %s returned False, stopping"
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@ -349,7 +387,7 @@ class RcInstruction(abc.ABC):
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Args:
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host_name: the name of the host to execute the instruction for
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variables: the variables cache
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variables: the variable storage instance
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Returns:
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``True`` if there is no conditional clause for this instruction, or
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@ -377,7 +415,7 @@ class RcInstruction(abc.ABC):
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Args:
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host_name: the name of the host to execute the instruction for
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variables: the variables cache
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variables: the variable storage instance
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Returns:
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the list of items to iterate over
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@ -399,7 +437,7 @@ class RcInstruction(abc.ABC):
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then return it.
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Args:
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variables: the variables cache
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variables: the variable storage instance
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may_be_template: a flag that indicates whether the name should be \
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processed with the templar.
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name: the name or its template
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@ -430,7 +468,7 @@ class RcInstruction(abc.ABC):
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return real_name
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@abc.abstractmethod
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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"""Execute the instruction.
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This method must be overridden to implement the actual action of the
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@ -477,7 +515,7 @@ class RciCreateGroup(RcInstruction):
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record, "parent"
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)
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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assert not (
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self._group_mbt is None
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or self._group_name is None
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@ -485,9 +523,9 @@ class RciCreateGroup(RcInstruction):
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)
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if self._parent_name is not None:
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parent = self.get_templated_group(
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merged_vars, self._parent_mbt, self._parent_name, must_exist=True
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variables, self._parent_mbt, self._parent_name, must_exist=True
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)
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name = self.get_templated_group(merged_vars, self._group_mbt, self._group_name)
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name = self.get_templated_group(variables, self._group_mbt, self._group_name)
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self._inventory.add_group(name)
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self._display.vvv("- created group %s" % (name,))
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if self._parent_name is not None:
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@ -512,10 +550,10 @@ class RciAddHost(RcInstruction):
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assert self._may_be_template is None and self._group is None
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self._may_be_template, self._group = self.parse_group_name(record, "group")
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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assert not (self._may_be_template is None or self._group is None)
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name = self.get_templated_group(
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merged_vars, self._may_be_template, self._group, must_exist=True
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variables, self._may_be_template, self._group, must_exist=True
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)
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self._inventory.add_child(name, host_name)
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self._display.vvv("- added host %s to %s" % (host_name, name))
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@ -543,14 +581,14 @@ class RciAddChild(RcInstruction):
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self._group_mbt, self._group_name = self.parse_group_name(record, "group")
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self._child_mbt, self._child_name = self.parse_group_name(record, "child")
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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assert not (self._group_mbt is None or self._group_name is None)
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assert not (self._child_mbt is None or self._child_name is None)
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group = self.get_templated_group(
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merged_vars, self._group_mbt, self._group_name, must_exist=True
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variables, self._group_mbt, self._group_name, must_exist=True
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)
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child = self.get_templated_group(
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merged_vars, self._child_mbt, self._child_name, must_exist=True
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variables, self._child_mbt, self._child_name, must_exist=True
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)
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self._inventory.add_child(group, child)
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self._display.vvv("- added group %s to %s" % (child, group))
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@ -595,13 +633,13 @@ class RciSetVarOrFact(RcInstruction):
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self._var_name = name
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self._var_value = record["value"]
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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assert not (
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self._var_name is None
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or self._name_may_be_template is None
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or self._var_value is None
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)
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self._templar.available_variables = merged_vars
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self._templar.available_variables = variables
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if self._name_may_be_template:
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name = self._templar.template(self._var_name)
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if not isinstance(name, string_types):
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@ -618,12 +656,9 @@ class RciSetVarOrFact(RcInstruction):
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value = self._templar.template(self._var_value)
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if self._is_fact:
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self._inventory.set_variable(host_name, name, value)
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host_vars[name] = value
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if name not in script_vars:
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merged_vars[name] = value
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variables._set_host_var(name, value)
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else:
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script_vars[name] = value
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merged_vars[name] = value
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variables[name] = value
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self._display.vvv(
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"- set %s %s to %s"
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% ("fact" if self._is_fact else "var", name, repr(value))
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def parse_action(self, record):
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pass
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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self._display.vvv("- stopped execution")
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return False
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@ -657,11 +692,11 @@ class RciFail(RcInstruction):
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def parse_action(self, record):
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self._message = record.get("msg", None)
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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if self._message is None:
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message = "fail requested (%s)" % (host_name,)
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else:
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self._templar.available_variables = merged_vars
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self._templar.available_variables = variables
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message = self._templar.template(self._message)
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self._display.vvv("- failed with message %s" % (message,))
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raise AnsibleRuntimeError(message)
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@ -753,48 +788,38 @@ class RciBlock(RcInstruction):
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)
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return instructions
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def execute_action(self, host_name, merged_vars, host_vars, script_vars):
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def execute_action(self, host_name, variables):
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assert not (
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self._block is None
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or self._rescue is None
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or self._always is None
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or self._locals is None
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)
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mv_copy = merged_vars.copy()
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sv_copy = script_vars.copy()
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self._templar.available_variables = mv_copy
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variables._script_stack_push()
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self._templar.available_variables = variables
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for key, value in self._locals.items():
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result = self._templar.template(value)
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sv_copy[key] = result
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mv_copy[key] = result
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variables[key] = result
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self._display.vvv("- set block-local %s to %s" % (key, result))
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try:
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try:
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self._display.vvv("- running 'block' instructions")
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return self.run_block(
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self._block, host_name, mv_copy, host_vars, sv_copy
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)
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return self.run_block(self._block, host_name, variables)
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except AnsibleError as e:
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if not self._rescue:
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self._display.vvv("- block failed")
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raise
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self._display.vvv("- block failed, running 'rescue' instructions")
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sv_copy["reconstructed_error"] = str(e)
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mv_copy["reconstructed_error"] = str(e)
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return self.run_block(
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self._rescue, host_name, mv_copy, host_vars, sv_copy
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)
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variables["reconstructed_error"] = str(e)
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return self.run_block(self._rescue, host_name, variables)
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finally:
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self._display.vvv("- block exited, running 'always' instructions")
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self.run_block(self._always, host_name, mv_copy, host_vars, sv_copy)
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# Reset merged vars, as the host vars may have changed.
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merged_vars.clear()
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merged_vars.update(host_vars)
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merged_vars.update(script_vars)
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self.run_block(self._always, host_name, variables)
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variables._script_stack_pop()
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def run_block(self, block, host_name, merged_vars, host_vars, script_vars):
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def run_block(self, block, host_name, variables):
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for instruction in block:
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if not instruction.run_for(host_name, merged_vars, host_vars, script_vars):
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if not instruction.run_for(host_name, variables):
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return False
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return True
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@ -851,10 +876,9 @@ class InventoryModule(BaseInventoryPlugin):
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def exec_for_host(self, host, instructions):
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host_vars = self.inventory.get_host(host).get_vars()
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var_cache = host_vars.copy()
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script_vars = {}
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variables = VariableStorage(host_vars)
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for instruction in instructions:
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if not instruction.run_for(host, var_cache, host_vars, script_vars):
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if not instruction.run_for(host, variables):
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return
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def dump_program(self, instructions):
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Reference in a new issue