Added support for Context and Variable(s).

scripttease/parsers/utils.py

@@ -1,7 +1,9 @@
 # Imports
 
-from commonkit import any_list_item
+from commonkit import any_list_item, smart_cast, split_csv
+from configparser import RawConfigParser
 import logging
+import os
 from ..constants import LOGGER_NAME
 from .ini import Config
 
@@ -12,6 +14,10 @@ log = logging.getLogger(LOGGER_NAME)
 __all__ = (
     "filter_commands",
     "load_commands",
+    "load_config",
+    "load_variables",
+    "Context",
+    "Variable",
 )
 
 # Functions
@@ -108,3 +114,212 @@ def load_config(path, overlay="ubuntu", **kwargs):
         return None
 
     return _config
+
+
+def load_variables(path, environment=None):
+    """Load variables from a file.
+
+    :param path: The path to the file.
+    :type path: str
+
+    :param environment: Filter variables by the given environment name.
+    :type environment: str
+
+    :rtype: list[scripttease.parsers.utils.Variable]
+
+    """
+    if not os.path.exists(path):
+        log.warning("Path to variables file does not exist: %s" % path)
+        return list()
+
+    if path.endswith(".ini"):
+        return _load_variables_ini(path, environment=environment)
+    else:
+        log.warning("Variable file format is not currently supports: %s" % path)
+        return list()
+
+
+def _load_variables_ini(path, environment=None):
+    """Load variables from an INI file. See ``load_variables()``."""
+
+    ini = RawConfigParser()
+    ini.read(path)
+
+    a = list()
+    for section in ini.sections():
+        if ":" in section:
+            variable_name, _environment = section.split(":")
+        else:
+            _environment = None
+            variable_name = section
+
+        _kwargs = {
+            'environment': _environment,
+        }
+        for key, value in ini.items(section):
+            if key == "tags":
+                value = split_csv(value)
+            else:
+                value = smart_cast(value)
+
+            _kwargs[key] = value
+
+        a.append(Variable(variable_name, **_kwargs))
+
+    if environment is not None:
+        b = list()
+        for var in a:
+            if var.environment and var.environment == environment or var.environment is None:
+                b.append(var)
+
+        return b
+
+    return a
+
+# Classes
+
+
+class Context(object):
+    """A collection of variables."""
+
+    def __init__(self, **kwargs):
+        """Initialize the context.
+
+        kwargs are added as variable instances.
+
+        """
+        self.variables = dict()
+
+        for key, value in kwargs.items():
+            self.add(key, value)
+
+    def __getattr__(self, item):
+        if item in self.variables:
+            return self.variables[item].value
+
+        return None
+
+    def __repr__(self):
+        return "<%s (%s)>" % (self.__class__.__name__, len(self.variables))
+
+    def add(self, name, value, environment=None, tags=None):
+        """Add a variable to the context.
+
+        :param name: The name of the variable.
+        :type name: str
+
+        :param value: The value of the variable in this context.
+
+        :param environment: The environment name to which the variable applies. ``None`` applies to all environments.
+        :type environment: str
+
+        :param tags: A list of tags that describe the variable.
+        :type tags: list[str]
+
+        :rtype: scripttease.parsers.utils.Variable
+
+        :raise: RuntimeError
+        :raises: ``RuntimeError`` if the variable already exists.
+
+        """
+        if name in self.variables:
+            raise RuntimeError("Variable already exists: %s" % name)
+
+        v = Variable(name, value, environment=environment, tags=tags)
+        self.variables[name] = v
+
+        return v
+
+    def get(self, name, default=None):
+        """Get a the value of the variable from the context.
+
+        :param name: The name of the variable.
+        :type name: str
+
+        :param default: The default value to return.
+
+        """
+        if not self.has(name):
+            return default
+
+        return self.variables[name].value
+
+    def has(self, name):
+        """Indicates whether the named variable exists in this context, and whether the value is not ``None``.
+
+        :rtype: bool
+
+        """
+        if name not in self.variables:
+            return False
+
+        return self.variables[name].value is not None
+
+    def join(self, variables):
+        """Join a list of variables to the context.
+
+        :param variables: the list of variables to be added.
+        :type variables: list[scripttease.parsers.utils.Variable]
+
+        .. note::
+            This *replaces* a variable if it already exists.
+
+        """
+        for v in variables:
+            self.variables[v.name] = v
+
+    def mapping(self):
+        """Export the context as a dictionary.
+
+        :rtype: dict
+
+        """
+        values = dict()
+        for key, var in self.variables.items():
+            values[key] = var.value or var.default
+
+        return values
+
+    def merge(self, context):
+        """Merge another context with this one.
+
+        :param context: The context to be merged.
+        :type context: scripttease.parser.utils.Context
+
+        .. note::
+            Variables that exist in the current context are *not* replaced with variables from the provided context.
+
+        """
+        for name, var in context.variables.items():
+            if not self.has(name):
+                self.variables[name] = var
+
+
+class Variable(object):
+    """Represents a variable to be used in the context of pre-processing a config file."""
+
+    def __init__(self, name, value, **kwargs):
+        """Initialize a variable.
+
+        :param name: The variable name.
+        :type name: str
+
+        :param value: The value of the variable.
+
+        kwargs are added as attributes of the instance.
+
+        """
+        self.name = name
+        self.value = value
+
+        kwargs.setdefault("tags", list())
+        self._attributes = kwargs
+
+    def __eq__(self, other):
+        return self.value == other
+
+    def __getattr__(self, item):
+        return self._attributes.get(item)
+
+    def __repr__(self):
+        return "<%s %s>" % (self.__class__.__name__, self.name)

tests/examples/variables.ini

@@ -0,0 +1,15 @@
+[domain_name]
+value = example.com
+
+[domain_tld]
+value = example_com
+
+[debug_enabled:testing]
+value = True
+
+[postgres_version]
+value = 11
+tags = postgres
+
+[mailgun_domain:live]
+value = "mg.example.com

tests/test_library_commands_base.py

@@ -57,6 +57,10 @@ class TestCommand(object):
         assert c.sudo.user == "root"
         assert c.sudo.enabled is False
 
+    def test_is_itemized(self):
+        c = Command("ls -ls")
+        assert c.is_itemized is False
+
     def test_repr(self):
         c = Command("ls -ls", comment="listing")
         assert repr(c) == "<Command listing>"
@@ -94,6 +98,10 @@ class TestItemizedCommand(object):
         c = ItemizedCommand(python_pip, ["Pillow", "psycopg2-binary", "django"], "$item")
         assert c.has_attribute("testing") is False
 
+    def test_is_itemized(self):
+        c = ItemizedCommand(python_pip, ["Pillow", "psycopg2-binary", "django"], "$item")
+        assert c.is_itemized is True
+
     def test_repr(self):
         c = ItemizedCommand(python_pip, ["Pillow", "psycopg2-binary", "django"], "$item")
         assert repr(c) == "<ItemizedCommand python_pip>"
@@ -103,3 +111,20 @@ class TestItemizedCommand(object):
         assert c.testing is None
         c.set_attribute("testing", True)
         assert c.testing is True
+
+
+class TestSudo(object):
+
+    def test_bool(self):
+        s = Sudo()
+        assert bool(s) is False
+
+        s = Sudo(True)
+        assert bool(s) is True
+
+    def test_str(self):
+        s = Sudo()
+        assert str(s) == ""
+
+        s = Sudo(True)
+        assert str(s) == "sudo -u root"