1 files changed, 44 insertions, 0 deletions
diff --git a/tasks/_dry_run.py b/tasks/_dry_run.py
new file mode 100644
index 0000000..cedbdd4
--- /dev/null
+++ b/tasks/_dry_run.py
@@ -0,0 +1,44 @@
+# -*- coding: UTF-8 -*-
+"""
+Basic support to use a --dry-run mode w/ invoke tasks.
+
+.. code-block::
+
+    from ._dry_run import DryRunContext
+
+    @task
+    def destroy_something(ctx, path, dry_run=False):
+        if dry_run:
+            ctx = DryRunContext(ctx)
+
+        # -- DRY-RUN MODE: Only echos commands.
+        ctx.run("rm -rf {}".format(path))
+"""
+
+from __future__ import print_function
+
+class DryRunContext(object):
+    PREFIX = "DRY-RUN: "
+    SCHEMA = "{prefix}{command}"
+    SCHEMA_WITH_KWARGS = "{prefix}{command} (with kwargs={kwargs})"
+
+    def __init__(self, ctx=None, prefix=None, schema=None):
+        if prefix is None:
+            prefix = self.PREFIX
+        if schema is None:
+            schema = self.SCHEMA
+
+        self.ctx = ctx
+        self.prefix = prefix
+        self.schema = schema
+
+    def run(self, command, **kwargs):
+        message = self.schema.format(command=command,
+                                     prefix=self.prefix,
+                                     kwargs=kwargs)
+        print(message)
+
+
+    def sudo(self, command, **kwargs):
+        command2 = "sudo %s" % command
+        self.run(command2, **kwargs)