feat(cli): add remote build support for langgraph deploy (#7234)

**Description:** 

 - extend host_backend client with remote build support
- refactored `cli.py` for better clarity
- update tests

libs/cli/langgraph_cli/archive.py

@@ -0,0 +1,161 @@
+"""Create a tarball of project source for remote builds."""
+
+import os
+import pathlib
+import tarfile
+import tempfile
+from contextlib import contextmanager
+
+import click
+import pathspec
+
+from langgraph_cli.config import Config, _assemble_local_deps
+
+_WARN_SIZE = 50 * 1024 * 1024  # 50 MB
+_MAX_SIZE = 200 * 1024 * 1024  # 200 MB
+
+_ALWAYS_EXCLUDE = [
+    "__pycache__/",
+    ".git/",
+    ".venv/",
+    "venv/",
+    "node_modules/",
+    ".tox/",
+    ".mypy_cache/",
+]
+
+
+def _build_ignore_spec(directory: pathlib.Path) -> pathspec.PathSpec:
+    """Build a PathSpec combining built-in exclusions with .dockerignore and .gitignore.
+
+    Always excludes common non-source directories (_ALWAYS_EXCLUDE).  On top of
+    that, patterns from .dockerignore and .gitignore (if present) are merged in.
+    """
+    lines: list[str] = list(_ALWAYS_EXCLUDE)
+    for name in (".dockerignore", ".gitignore"):
+        ignore_file = directory / name
+        if ignore_file.is_file():
+            lines.extend(ignore_file.read_text(encoding="utf-8").splitlines())
+    return pathspec.PathSpec.from_lines("gitwildmatch", lines)
+
+
+def _tar_filter(tarinfo: tarfile.TarInfo) -> tarfile.TarInfo | None:
+    """Strip symlinks, hardlinks, and traversal paths from archive."""
+    if tarinfo.issym() or tarinfo.islnk():
+        return None
+    if ".." in tarinfo.name.split("/"):
+        return None
+    return tarinfo
+
+
+def _add_directory(
+    tar: tarfile.TarFile,
+    source_dir: pathlib.Path,
+    arcname_prefix: str | None,
+    ignore_spec: pathspec.PathSpec,
+) -> None:
+    """Recursively add a directory to the tarball under the given prefix.
+
+    If arcname_prefix is None, files are added at the archive root.
+    Paths matching ignore_spec are excluded.
+    """
+    for root, dirs, files in os.walk(source_dir):
+        rel_root = os.path.relpath(root, source_dir).replace(os.sep, "/")
+        dirs[:] = [
+            d
+            for d in dirs
+            if not ignore_spec.match_file(
+                f"{rel_root}/{d}/" if rel_root != "." else f"{d}/"
+            )
+        ]
+        for f in files:
+            full_path = os.path.join(root, f)
+            rel = os.path.relpath(full_path, source_dir).replace(os.sep, "/")
+            if ignore_spec.match_file(rel):
+                continue
+            arcname = f"{arcname_prefix}/{rel}" if arcname_prefix else rel
+            info = tar.gettarinfo(full_path, arcname=arcname)
+            filtered = _tar_filter(info)
+            if filtered is None:
+                continue
+            with open(full_path, "rb") as fobj:
+                tar.addfile(filtered, fobj)
+
+
+@contextmanager
+def create_archive(
+    config_path: pathlib.Path,
+    config: Config,
+):
+    """Context manager that creates a .tar.gz archive of the project source.
+
+    Uses _assemble_local_deps to discover local dependencies referenced in
+    langgraph.json, including those outside config.parent (monorepo case).
+
+    The archive preserves the real filesystem layout relative to the common
+    ancestor of config.parent and all external dependency directories, so that
+    relative references (e.g. `../shared-lib`) resolve correctly after
+    extraction.
+
+    Yields (archive_path, file_size, config_relative_path).  The temporary
+    directory holding the archive is cleaned up automatically on exit.
+    """
+    config_path = config_path.resolve()
+    context_dir = config_path.parent
+
+    local_deps = _assemble_local_deps(config_path, config)
+    extra_contexts = local_deps.additional_contexts or []
+
+    dirs_to_include = [context_dir] + list(extra_contexts)
+
+    common = context_dir
+    for d in extra_contexts:
+        common = pathlib.Path(os.path.commonpath([common, d]))
+
+    tmp_dir = tempfile.mkdtemp(prefix="langgraph-deploy-")
+    try:
+        archive_path = os.path.join(tmp_dir, "source.tar.gz")
+
+        added_dirs: set[str] = set()
+        with tarfile.open(archive_path, "w:gz") as tar:
+            for dir_path in dirs_to_include:
+                rel = dir_path.relative_to(common)
+                prefix = str(rel).replace(os.sep, "/") if str(rel) != "." else None
+                key = prefix or ""
+                if key in added_dirs:
+                    continue
+                added_dirs.add(key)
+                ignore_spec = _build_ignore_spec(dir_path)
+                _add_directory(
+                    tar, dir_path, arcname_prefix=prefix, ignore_spec=ignore_spec
+                )
+
+        file_size = os.path.getsize(archive_path)
+
+        config_rel = str(config_path.relative_to(common)).replace(os.sep, "/")
+
+        with tarfile.open(archive_path, "r:gz") as tar:
+            names = tar.getnames()
+            if config_rel not in names:
+                raise click.ClickException(
+                    f"Archive validation failed: {config_rel} not found in archive"
+                )
+
+        if file_size > _MAX_SIZE:
+            raise click.ClickException(
+                f"Source archive is {file_size / 1_048_576:.1f} MB, which exceeds the 200 MB limit. "
+                "Add large files to .dockerignore or .gitignore (model weights, data sets, etc.)."
+            )
+
+        if file_size > _WARN_SIZE:
+            click.secho(
+                f"   Warning: source archive is {file_size / 1_048_576:.1f} MB. "
+                "Consider adding large files to .dockerignore or .gitignore.",
+                fg="yellow",
+            )
+
+        yield archive_path, file_size, config_rel
+    finally:
+        import shutil
+
+        shutil.rmtree(tmp_dir, ignore_errors=True)