add ssh remote backend and streamapi wrapper

The ssh backend calls into another host and passes all information on
stdin/stdout/stderr. To do so, it uses a streamapi wrapper on the remote
side that itself calls into a regular backend.

1 files changed, 30 insertions, 6 deletions

diff --git a/mdbp/common.py b/mdbp/common.py
index 097c7a3..830aad7 100644
--- a/mdbp/common.py
+++ b/mdbp/common.py
@@ -9,6 +9,7 @@ import importlib.resources
 import json
 import multiprocessing
 import pathlib
+import tarfile
 import tempfile
 import typing
 import urllib.parse
@@ -29,15 +30,21 @@ def json_load(filecontextmanager:
 
 JsonObject = typing.Dict[str, typing.Any]
 
-def buildjson(filename: str) -> JsonObject:
-    """Type constructor for argparse validating a build json file path and
-    returning the parsed json object."""
-    buildobj = json_load(argparse.FileType("r")(filename))
+def buildjson_validate(buildobj: JsonObject) -> None:
+    """Validate the given build json object against the schema."""
     if jsonschema:
         jsonschema.validate(
             buildobj,
             json_load(
                 importlib.resources.open_text("mdbp", "build_schema.json")))
+
+def buildjson_patch_relative(buildobj: JsonObject,
+                             basedir: pathlib.PurePath) -> None:
+    """Resolve relative paths used in the buildobj using the given basedir:
+     * .input.dscpath
+     * .output.directory
+    The operation is performed in-place and modifes the given buildobj.
+    """
     for attrs in (("input", "dscpath"), ("output", "directory")):
         obj = buildobj
         for attr in attrs[:-1]:
@@ -47,10 +54,16 @@ def buildjson(filename: str) -> JsonObject:
                 break
         else:
             try:
-                obj[attrs[-1]] = str(pathlib.Path(filename).parent /
-                                     pathlib.Path(obj[attrs[-1]]))
+                obj[attrs[-1]] = str(basedir / pathlib.Path(obj[attrs[-1]]))
             except KeyError:
                 pass
+
+def buildjson(filename: str) -> JsonObject:
+    """Type constructor for argparse validating a build json file path and
+    returning the parsed json object."""
+    buildobj = json_load(argparse.FileType("r")(filename))
+    buildjson_validate(buildobj)
+    buildjson_patch_relative(buildobj, pathlib.Path(filename).parent)
     assert isinstance(buildobj, dict)
     return buildobj
 
@@ -153,3 +166,14 @@ def make_option(optname: str, value: typing.Optional[str]) -> typing.List[str]:
 def profile_option(build: JsonObject, optname: str) -> typing.List[str]:
     """Construct the option for specifying build profiles if required."""
     return make_option(optname, ",".join(build.get("profiles", ())))
+
+def tar_add(tarobj: tarfile.TarFile, path: pathlib.Path) -> None:
+    """Add the given file as its basename to the tarobj retaining its
+    modification time, but no mode or ownership information.
+    """
+    info = tarfile.TarInfo(path.name)
+    statres = path.stat()
+    info.size = statres.st_size
+    info.mtime = int(statres.st_mtime)
+    with path.open("rb") as fobj:
+        tarobj.addfile(info, fobj)