Fixed logic of pulling examples from cli in edge cases of unreleased zenml

Author: htahir1

docs/book/guides/post-execution-workflow-test.md

@@ -0,0 +1,110 @@
+# Post Execution Workflow
+
+## Post-execution workflow
+
+After executing a pipeline, the user needs to be able to fetch it from history and perform certain tasks. This page captures these workflows at an orbital level.
+
+## Component Hierarchy
+
+
+In the context of a post-execution workflow, there is an implied hierarchy of some basic ZenML components:
+
+```bash
+repository -> pipelines -> runs -> steps -> outputs
+
+# where -> implies a 1-many relationship.
+```
+
+### Repository
+
+The highest level `repository` object is where to start from.
+
+
+### Define standard ML steps
+
+```python
+@trainer
+def trainer(dataset: torch.Dataset) -> torch.nn.Module:
+   ... 
+   return model
+```
+
+
+
+### Get pipelines and runs
+
+```python
+pipelines = repo.get_pipelines()   # get all pipelines from all stacks
+pipeline = repo.get_pipeline(pipeline_name=..., stack_key=...)
+```
+
+```python
+runs = pipeline.get_runs()  # all runs of a pipeline chronlogically ordered
+run = runs[-1]  # latest run
+output = step.outputs[0]  # get outputs
+```
+
+### Materializing outputs (or inputs)
+
+Once an output artifact is acquired from history, one can visualize it with any chosen `Materializer`.
+
+```python
+df = output.read(materializer=PandasMaterializer)  # get data
+
+```
+
+### Seeing statistics and schema
+
+```python
+stats = output.read(materializer=StatisticsMaterializer)  # get stats
+schema = output.read(materializer=SchemaMaterializer)  # get schema
+```
+
+### Retrieving Model
+
+```python
+model = output.read(materializer=KerasModelMaterializer)  # get model
+```
+
+
+
+#### Pipelines
+
+```python
+# get all pipelines from all stacks
+pipelines = repo.get_pipelines()  
+
+# or get one pipeline by name and/or stack key
+pipeline = repo.get_pipeline(pipeline_name=..., stack_key=...)
+```
+
+#### Runs
+
+```python
+
+```
+
+#### Steps
+
+```python
+# at this point we switch from the `get_` paradigm to properties
+steps = run.steps  # all steps of a pipeline
+step = steps[0] 
+print(step.name)
+```
+
+#### Outputs
+
+```python
+# all outputs of a step
+# if one output, then its the first element in the list
+# if multiple output, then in the order defined with the `Output`
+
+
+# will get you the value from the original materializer used in the pipeline
+output.read()  
+```
+
+## Visuals
+
+

docs/interrogate.svg

@@ -34,12 +34,16 @@
 
 
 class GitExamplesHandler(object):
+    """Handles logic related to cloning and checking out the ZenML Git
+    repository, in relation to the `examples` dir."""
+
     def __init__(self, redownload: str = "") -> None:
         """Initialize the GitExamplesHandler class."""
         self.clone_repo(redownload)
 
     def clone_repo(self, redownload_version: str = "") -> None:
-        """Clone ZenML git repo into global config directory if not already cloned"""
+        """Clone ZenML git repo into global config directory if not already
+        cloned"""
         installed_version = zenml_version_installed
         repo_dir = click.get_app_dir(APP_NAME)
         examples_dir = os.path.join(repo_dir, EXAMPLES_GITHUB_REPO)
@@ -54,39 +58,55 @@ def clone_repo(self, redownload_version: str = "") -> None:
             redownload_version
             or EXAMPLES_GITHUB_REPO not in config_directory_files
         ):
-            self.clone_from_zero(GIT_REPO_URL, examples_dir, installed_version)
+            self.clone_from_zero(GIT_REPO_URL, examples_dir)
+            repo = Repo(examples_dir)
+            self.checkout_repository(repo, installed_version)
 
-    def clone_from_zero(
-        self, git_repo_url: str, local_dir: str, version: str
-    ) -> None:
+    def clone_from_zero(self, git_repo_url: str, local_dir: str) -> None:
         """Basic functionality to clone a repo."""
         try:
-            Repo.clone_from(git_repo_url, local_dir, branch=version)
-        except GitCommandError:
-            error(
-                f"You just tried to download examples for version {version}. "
-                f"There is no corresponding release or version. Please try "
-                f"again with a version number corresponding to an actual release."
-            )
+            Repo.clone_from(git_repo_url, local_dir, branch="main")
         except KeyboardInterrupt:
             self.delete_example_source_dir(local_dir)
+            error("Cancelled download of repository.. Rolled back.")
+            return
 
     def checkout_repository(
-        self, repository: Repo, desired_version: str
+        self,
+        repository: Repo,
+        desired_version: str,
+        fallback_to_latest: bool = True,
     ) -> None:
         """Checks out a branch or tag of a git repository
 
         Args:
-            desired_version: a valid ZenML release version number
+            repository: a Git repository reference.
+            desired_version: a valid ZenML release version number.
+            fallback_to_latest: Whether to default to the latest released
+            version or not if `desired_version` does not exist.
         """
         try:
             repository.git.checkout(desired_version)
         except GitCommandError:
-            error(
-                f"You just tried to checkout the repository for version {desired_version}. "
-                f"There is no corresponding release or version. Please try "
-                f"again with a version number corresponding to an actual release."
-            )
+            if fallback_to_latest:
+                last_release = parse(repository.tags[-1].name)
+                repository.git.checkout(last_release)
+                warning(
+                    f"You just tried to download examples for version "
+                    f"{desired_version}. "
+                    f"There is no corresponding release or version. We are "
+                    f"going to "
+                    f"default to the last release: {last_release}"
+                )
+            else:
+                error(
+                    f"You just tried to checkout the repository for version "
+                    f"{desired_version}. "
+                    f"There is no corresponding release or version. Please try "
+                    f"again with a version number corresponding to an actual "
+                    f"release."
+                )
+                raise
 
     def clone_when_examples_already_cloned(
         self, local_dir: str, version: str
@@ -95,20 +115,12 @@ def clone_when_examples_already_cloned(
         into the global config directory if they are already cloned."""
         local_dir_path = Path(local_dir)
         repo = Repo(str(local_dir_path))
-
-        last_release = parse(repo.tags[-1].name)
         desired_version = parse(version)
-
-        if last_release < desired_version:
-            warning(
-                f"You tried to download {desired_version}."
-                f"The latest version you currently have available is {last_release}."
-                f"Recloning the repository from scratch to try to obtain {desired_version}"
-            )
-            self.delete_example_source_dir(str(local_dir_path))
-            self.clone_from_zero(GIT_REPO_URL, local_dir, str(desired_version))
-        else:
-            self.checkout_repository(repo, str(desired_version))
+        self.delete_example_source_dir(str(local_dir_path))
+        self.clone_from_zero(GIT_REPO_URL, local_dir)
+        self.checkout_repository(
+            repo, str(desired_version), fallback_to_latest=False
+        )
 
     def get_examples_dir(self) -> str:
         """Return the examples dir"""
@@ -155,11 +167,13 @@ def delete_example_source_dir(self, source_path: str) -> None:
             path_utils.rm_dir(source_path)
         else:
             raise ValueError(
-                "You can only delete the source directory from your ZenML config directory"
+                "You can only delete the source directory from your ZenML "
+                "config directory"
             )
 
     def delete_working_directory_examples_folder(self) -> None:
-        """Delete the zenml_examples folder from the current working directory."""
+        """Delete the zenml_examples folder from the current working
+        directory."""
         cwd_directory_path = os.path.join(os.getcwd(), EXAMPLES_GITHUB_REPO)
         if os.path.exists(cwd_directory_path):
             path_utils.rm_dir(str(cwd_directory_path))
@@ -193,7 +207,8 @@ def list(git_examples_handler: Any) -> None:
 # TODO: [MEDIUM] Use a better type for the git_examples_handler
 def info(git_examples_handler: Any, example_name: str) -> None:
     """Find out more about an example."""
-    # TODO: [MEDIUM] fix markdown formatting so that it looks nicer (not a pure .md dump)
+    # TODO: [MEDIUM] fix markdown formatting so that it looks nicer (not a
+    #  pure .md dump)
     example_dir = os.path.join(
         git_examples_handler.get_examples_dir(), example_name
     )
@@ -221,7 +236,8 @@ def info(git_examples_handler: Any, example_name: str) -> None:
     "--force",
     "-f",
     is_flag=True,
-    help="Force the redownload of the examples folder to the ZenML config folder.",
+    help="Force the redownload of the examples folder to the ZenML config "
+    "folder.",
 )
 @click.option(
     "--version",

src/zenml/cli/example.py

@@ -19,7 +19,6 @@
 from click.testing import CliRunner
 from git.repo.base import Repo
 
-from zenml import __version__ as running_zenml_version
 from zenml.cli.example import EXAMPLES_GITHUB_REPO, info, list, pull
 from zenml.constants import APP_NAME
 from zenml.logger import get_logger
@@ -56,14 +55,6 @@ def test_info_returns_zero_exit_code(example: str) -> None:
         assert result.exit_code == 0
 
 
-def test_pull_command_returns_zero_exit_code() -> None:
-    """Check pull command exits without errors"""
-    runner = CliRunner()
-    with runner.isolated_filesystem():
-        result = runner.invoke(pull, ["-f", "-v", running_zenml_version])
-        assert result.exit_code == 0
-
-
 def test_pull_earlier_version_returns_zero_exit_code() -> None:
     """Check pull of earlier version exits without errors"""
     runner = CliRunner()