Add fetch command to download expedition data based on space_time_region from schedule.yaml

.readthedocs.yaml

@@ -2,7 +2,8 @@
 # See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
 
 version: 2
-
+sphinx:
+  configuration: docs/conf.py
 build:
   os: ubuntu-22.04
   tools:

environment.yml

@@ -11,6 +11,7 @@ dependencies:
   - pydantic >=2, <3
   - pip
   - pyyaml
+  - copernicusmarine >= 2
 
   # linting
   - pre-commit

pyproject.toml

@@ -33,6 +33,7 @@ dependencies = [
     "numpy >=1, < 2",
     "pydantic >=2, <3",
     "PyYAML",
+    "copernicusmarine >= 2",
 ]
 
 [project.urls]
@@ -104,6 +105,8 @@ ignore = [
     "D212",
     # one-blank-line-before-class
     "D203",
+    # First line of docstring should be in imperative mood
+    "D401",
 
     # TODO: Remove later
     "D100", "D103"

src/virtualship/cli/_creds.py

@@ -0,0 +1,107 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import click
+import pydantic
+import yaml
+
+CREDENTIALS_FILE = "credentials.yaml"
+
+
+class CredentialFileError(Exception):
+    """Exception raised for errors in the input file format."""
+
+    pass
+
+
+class Credentials(pydantic.BaseModel):
+    """Credentials to be used in `virtualship fetch` command."""
+
+    COPERNICUS_USERNAME: str
+    COPERNICUS_PASSWORD: str
+
+    @classmethod
+    def from_yaml(cls, path: str | Path) -> Credentials:
+        """
+        Load credentials from a yaml file.
+
+        :param path: Path to the file to load from.
+        :returns Credentials: The credentials.
+        """
+        with open(path) as file:
+            data = yaml.safe_load(file)
+
+        if not isinstance(data, dict):
+            raise CredentialFileError("Credential file is of an invalid format.")
+
+        return cls(**data)
+
+    def dump(self) -> str:
+        """
+        Dump credentials to a yaml string.
+
+        :param creds: The credentials to dump.
+        :returns str: The yaml string.
+        """
+        return yaml.safe_dump(self.model_dump())
+
+    def to_yaml(self, path: str | Path) -> None:
+        """
+        Write credentials to a yaml file.
+
+        :param path: Path to the file to write to.
+        """
+        with open(path, "w") as file:
+            file.write(self.dump())
+
+
+def get_dummy_credentials_yaml() -> str:
+    return (
+        Credentials(
+            COPERNICUS_USERNAME="my_username", COPERNICUS_PASSWORD="my_password"
+        )
+        .dump()
+        .strip()
+    )
+
+
+def get_credentials_flow(
+    username: str | None, password: str | None, creds_path: Path
+) -> tuple[str, str]:
+    """
+    Execute flow of getting credentials for use in the `fetch` command.
+
+    - If username and password are provided via CLI, use them (ignore the credentials file if exists).
+    - If username and password are not provided, try to load them from the credentials file.
+    - If no credentials are provided, print a message on how to make credentials file and prompt for credentials.
+
+    :param username: The username provided via CLI.
+    :param password: The password provided via CLI.
+    :param creds_path: The path to the credentials file.
+    """
+    if username and password:
+        if creds_path.exists():
+            click.echo(
+                f"Credentials file exists at '{creds_path}', but username and password are already provided. Ignoring credentials file."
+            )
+        return username, password
+
+    try:
+        creds = Credentials.from_yaml(creds_path)
+        click.echo(f"Loaded credentials from '{creds_path}'.")
+        return creds.COPERNICUS_USERNAME, creds.COPERNICUS_PASSWORD
+    except FileNotFoundError:
+        msg = f"""Credentials not provided. Credentials can be obtained from https://data.marine.copernicus.eu/register. Either pass in via `--username` and `--password` arguments, or via config file at '{creds_path}'. Config file should be YAML along following format:
+### {creds_path}
+
+{get_dummy_credentials_yaml().strip()}
+
+###
+
+Prompting for credentials instead...
+"""
+        click.echo(msg)
+        username = click.prompt("username")
+        password = click.prompt("password", hide_input=True)
+        return username, password