Merge pull request #23 from tiangolo/progressbar

📝 Add docs for progress bars.

docs/src/progressbar/tutorial001.py

@@ -0,0 +1,17 @@
+import time
+
+import typer
+
+
+def main():
+    total = 0
+    with typer.progressbar(range(100)) as progress:
+        for value in progress:
+            # Fake processing time
+            time.sleep(0.01)
+            total += 1
+    typer.echo(f"Processed {total} things.")
+
+
+if __name__ == "__main__":
+    typer.run(main)

docs/src/progressbar/tutorial002.py

@@ -0,0 +1,23 @@
+import time
+
+import typer
+
+
+def iterate_user_ids():
+    # Let's imagine this is a web API, not a range()
+    for i in range(100):
+        yield i
+
+
+def main():
+    total = 0
+    with typer.progressbar(iterate_user_ids(), length=100) as progress:
+        for value in progress:
+            # Fake processing time
+            time.sleep(0.01)
+            total += 1
+    typer.echo(f"Processed {total} user IDs.")
+
+
+if __name__ == "__main__":
+    typer.run(main)

docs/src/progressbar/tutorial003.py

@@ -0,0 +1,17 @@
+import time
+
+import typer
+
+
+def main():
+    total = 0
+    with typer.progressbar(range(100), label="Processing") as progress:
+        for value in progress:
+            # Fake processing time
+            time.sleep(0.01)
+            total += 1
+    typer.echo(f"Processed {total} things.")
+
+
+if __name__ == "__main__":
+    typer.run(main)

docs/src/progressbar/tutorial004.py

@@ -0,0 +1,17 @@
+import time
+
+import typer
+
+
+def main():
+    total = 1000
+    with typer.progressbar(length=total) as progress:
+        for batch in range(4):
+            # Fake processing time
+            time.sleep(1)
+            progress.update(2500)
+    typer.echo(f"Processed {total} things in batches.")
+
+
+if __name__ == "__main__":
+    typer.run(main)

docs/tutorial/progressbar.md

@@ -0,0 +1,139 @@
+If you are executing an operation that can take some time, you can inform it to the user with a progress bar.
+
+For this, you can use `typer.progressbar()`:
+
+```Python hl_lines="8"
+{!./src/progressbar/tutorial001.py!}
+```
+
+You use `typer.progressbar()` with a `with` statement, as in:
+
+```Python
+with typer.progressbar(something) as progress:
+    pass
+```
+
+And you pass as function argument to `typer.progressbar()` the thing that you would normally iterate over.
+
+So, if you have a list of users, this could be:
+
+```Python
+users = ["Camila", "Rick", "Morty"]
+
+with typer.progressbar(users) as progress:
+    pass
+```
+
+And the `with` statement using `typer.progressbar()` gives you an object that you can iterate over, just like if it was the same thing that you would iterate over normally.
+
+But by iterating over this object **Typer** (actually Click) will know to update the progress bar:
+
+```Python
+users = ["Camila", "Rick", "Morty"]
+
+with typer.progressbar(users) as progress:
+    for user in progress:
+        typer.echo(user)
+```
+
+!!! tip
+    Notice that there are 2 levels of code blocks. One for the `with` statement and one for the `for` statement.
+
+!!! info
+    This is mostly useful for operations that take some time.
+
+    In the example above we are faking it with `time.sleep()`.
+
+Check it:
+
+<div class="termy">
+
+```console
+$ python main.py
+
+---> 100%
+
+Processed 100 things.
+```
+
+</div>
+
+## Setting a Progress Bar `length`
+
+The progress bar is generated from the length of the iterable (e.g. the list of users).
+
+But if the length is not available (for example, with something that fetches a new user from a web API each time) you can pass an explicit `length` to `typer.progressbar()`.
+
+```Python hl_lines="14"
+{!./src/progressbar/tutorial002.py!}
+```
+
+Check it:
+
+<div class="termy">
+
+```console
+$ python main.py
+
+---> 100%
+
+Processed 100 user IDs.
+```
+
+</div>
+
+### About the function with `yield`
+
+If you hadn't seen something like that `yield` above, that's a "<a href="https://docs.python.org/3/glossary.html#term-generator" target="_blank">generator</a>".
+
+You can iterate over that function with a `for` and at each iteration it will give you the value at `yield`.
+
+`yield` is like a `return` that gives values multiple times and let's you use the function in a `for` loop.
+
+For example:
+
+```Python
+def iterate_user_ids():
+    # Let's imagine this is a web API, not a range()
+    for i in range(100):
+        yield i
+
+for i in iterate_user_ids():
+    print(i)
+```
+
+would print each of the "user IDs" (here it's just the numbers from `0` to `99`).
+
+## Add a `label`
+
+You can also set a `label`:
+
+```Python hl_lines="8"
+{!./src/progressbar/tutorial003.py!}
+```
+
+Check it:
+
+<div class="use-termynal">
+<span data-ty="input">python main.py</span>
+<span data-ty="progress" data-ty-prompt="Processing"></span>
+<span data-ty>Processed 100 things.</span>
+</div>
+
+## Iterate manually
+
+If you need to manually iterate over something and update the progress bar irregularly, you can do it by not passing an iterable but just a `length` to `typer.progressbar()`.
+
+And then calling the `.update()` method in the object from the `with` statement:
+
+```Python hl_lines="8  12"
+{!./src/progressbar/tutorial004.py!}
+```
+
+Check it:
+
+<div class="use-termynal">
+<span data-ty="input">python main.py</span>
+<span data-ty="progress" data-ty-prompt="Batches"></span>
+<span data-ty>Processed 100 things in batches.</span>
+</div>

mkdocs.yml

@@ -48,6 +48,7 @@ nav:
             - Path: 'tutorial/parameter-types/path.md'
             - File: 'tutorial/parameter-types/file.md'
         - Ask with Prompt: 'tutorial/prompt.md'
+        - Progress Bar: 'tutorial/progressbar.md'
     - Alternatives, Inspiration and Comparisons: 'alternatives.md'
     - Help Typer - Get Help: 'help-typer.md'
     - Development - Contributing: 'contributing.md'

tests/test_tutorial/test_commands/test_help/test_tutorial002.py

@@ -26,7 +26,7 @@ def test_help_create():
     assert "Some internal utility function to create." not in result.output
 
 
-def test_help_create():
+def test_help_delete():
     result = runner.invoke(app, ["delete", "--help"])
     assert result.exit_code == 0
     assert "Delete a user with USERNAME." in result.output