feat: Extensions module

openhands-sdk/openhands/sdk/extensions/fetch.py

@@ -0,0 +1,278 @@
+"""Fetching utilities for extensions."""
+
+import hashlib
+from enum import StrEnum
+from pathlib import Path
+
+from openhands.sdk.git.cached_repo import GitHelper, try_cached_clone_or_update
+from openhands.sdk.git.utils import extract_repo_name, is_git_url, normalize_git_url
+from openhands.sdk.logger import get_logger
+
+
+logger = get_logger(__name__)
+
+
+class ExtensionFetchError(Exception):
+    """Raised when fetching an extension fails."""
+
+
+class SourceType(StrEnum):
+    """Classification of an extension source.
+
+    LOCAL   -- a filesystem path (absolute, home-relative, or dot-relative).
+    GIT     -- any git-clonable URL (HTTPS, SSH, git://, etc.).
+    GITHUB  -- the ``github:owner/repo`` shorthand, expanded to an HTTPS URL.
+    """
+
+    LOCAL = "local"
+    GIT = "git"
+    GITHUB = "github"
+
+
+def parse_extension_source(source: str) -> tuple[SourceType, str]:
+    """Parse extension source into (SourceType, url).
+
+    Args:
+        source: Extension source string. Can be:
+            - "github:owner/repo" - GitHub repository shorthand
+            - "https://github.com/owner/repo.git" - Full git URL
+            - "git@github.com:owner/repo.git" - SSH git URL
+            - "/local/path" - Local path
+
+    Returns:
+        Tuple of (source_type, normalized_url) where source_type is one of:
+        - SourceType.GITHUB: GitHub repository
+        - SourceType.GIT: Any git URL
+        - SourceType.LOCAL: Local filesystem path
+
+    Examples:
+        >>> parse_extension_source("github:owner/repo")
+        (SourceType.GITHUB, "https://github.com/owner/repo.git")
+        >>> parse_extension_source("https://gitlab.com/org/repo.git")
+        (SourceType.GIT, "https://gitlab.com/org/repo.git")
+        >>> parse_extension_source("/local/path")
+        (SourceType.LOCAL, "/local/path")
+    """
+    source = source.strip()
+
+    # GitHub shorthand: github:owner/repo
+    if source.startswith("github:"):
+        repo_path = source[7:]  # Remove "github:" prefix
+        # Validate format
+        if "/" not in repo_path or repo_path.count("/") > 1:
+            raise ExtensionFetchError(
+                f"Invalid GitHub shorthand format: {source}. "
+                f"Expected format: github:owner/repo"
+            )
+        url = f"https://github.com/{repo_path}.git"
+        return (SourceType.GITHUB, url)
+
+    # Git URLs: detect by protocol/scheme rather than enumerating providers
+    # This handles GitHub, GitLab, Bitbucket, Codeberg, self-hosted instances, etc.
+    if is_git_url(source):
+        url = normalize_git_url(source)
+        return (SourceType.GIT, url)
+
+    # Local path: starts with /, ~, . or contains / without a URL scheme
+    if source.startswith(("/", "~", ".")):
+        return (SourceType.LOCAL, source)
+
+    if "/" in source and "://" not in source:
+        # Relative path like "plugins/my-plugin"
+        return (SourceType.LOCAL, source)
+
+    raise ExtensionFetchError(
+        f"Unable to parse extension source: {source}. "
+        f"Expected formats: 'github:owner/repo', git URL, or local path"
+    )
+
+
+def _resolve_local_source(url: str) -> Path:
+    """Resolve a local extension source to a path.
+
+    Args:
+        url: Local path string (may contain ~ for home directory).
+
+    Returns:
+        Resolved absolute path to the extension directory.
+
+    Raises:
+        ExtensionFetchError: If path doesn't exist.
+    """
+    local_path = Path(url).expanduser().resolve()
+    if not local_path.exists():
+        raise ExtensionFetchError(f"Local extension path does not exist: {local_path}")
+    return local_path
+
+
+def _apply_subpath(base_path: Path, subpath: str | None, context: str) -> Path:
+    """Apply a subpath to a base path, validating it exists.
+
+    Args:
+        base_path: The root path.
+        subpath: Optional subdirectory path (may have leading/trailing slashes).
+        context: Description for error messages (e.g., "extension repository").
+
+    Returns:
+        The final path (base_path if no subpath, otherwise base_path/subpath).
+
+    Raises:
+        ExtensionFetchError: If subpath doesn't exist.
+    """
+    if not subpath:
+        return base_path
+
+    final_path = base_path / subpath.strip("/")
+    if not final_path.exists():
+        raise ExtensionFetchError(f"Subdirectory '{subpath}' not found in {context}")
+    return final_path
+
+
+def fetch(
+    source: str,
+    cache_dir: Path,
+    ref: str | None = None,
+    update: bool = True,
+    repo_path: str | None = None,
+    git_helper: GitHelper | None = None,
+) -> Path:
+    """Fetch an extension from a source and return the local path.
+
+    Args:
+        source: Extension source -- git URL, GitHub shorthand, or local path.
+        cache_dir: Directory for caching.
+        ref: Optional branch, tag, or commit to checkout.
+        update: If true and cache exists, update it.
+        repo_path: Subdirectory path within the repository.
+        git_helper: GitHelper instance (for testing).
+
+    Returns:
+        Path to the local extension directory.
+    """
+    path, _ = fetch_with_resolution(
+        source=source,
+        cache_dir=cache_dir,
+        ref=ref,
+        update=update,
+        repo_path=repo_path,
+        git_helper=git_helper,
+    )
+    return path
+
+
+def fetch_with_resolution(
+    source: str,
+    cache_dir: Path,
+    ref: str | None = None,
+    update: bool = True,
+    repo_path: str | None = None,
+    git_helper: GitHelper | None = None,
+) -> tuple[Path, str | None]:
+    """Fetch an extension and return both the path and resolved commit SHA.
+
+    Args:
+        source: Extension source (git URL, GitHub shorthand, or local path).
+        cache_dir: Directory for caching.
+        ref: Optional branch, tag, or commit to checkout.
+        update: If True and cache exists, update it.
+        repo_path: Subdirectory path within the repository.
+        git_helper: GitHelper instance (for testing).
+
+    Returns:
+        Tuple of (path, resolved_ref) where resolved_ref is the commit SHA for git
+        sources and None for local paths.
+
+    Raises:
+        ExtensionFetchError: If fetching the extension fails.
+    """
+    source_type, url = parse_extension_source(source)
+
+    if source_type == SourceType.LOCAL:
+        if repo_path is not None:
+            raise ExtensionFetchError(
+                f"repo_path is not supported for local extension sources. "
+                f"Specify the full path directly instead of "
+                f"source='{source}' + repo_path='{repo_path}'"
+            )
+        return _resolve_local_source(url), None
+
+    git = git_helper if git_helper is not None else GitHelper()
+
+    ext_path, resolved_ref = _fetch_remote_source_with_resolution(
+        url, cache_dir, ref, update, repo_path, git, source
+    )
+    return ext_path, resolved_ref
+
+
+def get_cache_path(source: str, cache_dir: Path) -> Path:
+    """Get the cache path for an extension source.
+
+    Creates a deterministic path based on a hash of the source URL.
+
+    Args:
+        source: The extension source (URL or path).
+        cache_dir: Base cache directory.
+
+    Returns:
+        Path where the extension should be cached.
+    """
+    # Create a hash of the source for the directory name
+    source_hash = hashlib.sha256(source.encode()).hexdigest()[:16]
+
+    # Extract repo name for human-readable cache directory name
+    readable_name = extract_repo_name(source)
+
+    cache_name = f"{readable_name}-{source_hash}"
+    return cache_dir / cache_name
+
+
+def _fetch_remote_source_with_resolution(
+    url: str,
+    cache_dir: Path,
+    ref: str | None,
+    update: bool,
+    subpath: str | None,
+    git_helper: GitHelper,
+    source: str,
+) -> tuple[Path, str]:
+    """Fetch a remote extension source and return path + resolved commit SHA.
+
+    Args:
+        url: Git URL to fetch.
+        cache_dir: Base directory for caching.
+        ref: Optional branch, tag, or commit to checkout.
+        update: Whether to update existing cache.
+        subpath: Optional subdirectory within the repository.
+        git_helper: GitHelper instance for git operations.
+        source: Original source string (for error messages).
+
+    Returns:
+        Tuple of (path, resolved_ref) where resolved_ref is the commit SHA.
+
+    Raises:
+        ExtensionFetchError: If fetching fails or subpath is invalid.
+    """
+    repo_cache_path = get_cache_path(url, cache_dir)
+    cache_dir.mkdir(parents=True, exist_ok=True)
+
+    result = try_cached_clone_or_update(
+        url=url,
+        repo_path=repo_cache_path,
+        ref=ref,
+        update=update,
+        git_helper=git_helper,
+    )
+
+    if result is None:
+        raise ExtensionFetchError(f"Failed to fetch extension from {source}")
+
+    # Get the actual commit SHA that was checked out
+    try:
+        resolved_ref = git_helper.get_head_commit(repo_cache_path)
+    except Exception as e:
+        logger.warning(f"Could not get commit SHA for {source}: {e}")
+        # Fall back to the requested ref if we can't get the SHA
+        resolved_ref = ref or "HEAD"
+
+    final_path = _apply_subpath(repo_cache_path, subpath, "extension repository")
+    return final_path, resolved_ref