feat(snaps): inject snaps from host if try to install same channel

craft_providers/actions/snap_installer.py

@@ -33,6 +33,7 @@
 from craft_providers.const import TIMEOUT_COMPLEX, TIMEOUT_SIMPLE
 from craft_providers.errors import (
     BaseConfigurationError,
+    IncompatibleSnapError,
     ProviderError,
     details_from_called_process_error,
 )
@@ -340,7 +341,13 @@ def inject_from_host(*, executor: Executor, snap_name: str, classic: bool) -> No
             classic,
         )
 
-    host_revision = get_host_snap_info(snap_name)["revision"]
+    host_snap_info = get_host_snap_info(snap_name)
+    host_snap_base = host_snap_info.get("base", None)
+    if host_snap_base:
+        logger.debug("Installing base snap %r from host", host_snap_base)
+        inject_from_host(executor=executor, snap_name=host_snap_base, classic=False)
+
+    host_revision = host_snap_info["revision"]
     target_revision = _get_snap_revision_ensuring_source(
         snap_name=snap_store_name,
         source=SNAP_SRC_HOST,
@@ -398,8 +405,41 @@ def inject_from_host(*, executor: Executor, snap_name: str, classic: bool) -> No
     )
 
 
+def _try_install_from_host(
+    *,
+    executor: Executor,
+    snap_name: str,
+    channel: str,
+    classic: bool,
+) -> None:
+    """Try to install snap from host if has same channel."""
+    try:
+        host_snap_info = get_host_snap_info(snap_name)
+    except requests.exceptions.HTTPError as error:
+        logger.debug(f"Host snap {snap_name} not exists, skipping")
+        raise IncompatibleSnapError(f"Host snap {snap_name} not exists") from error
+
+    if host_snap_info.get("channel", None) != channel:
+        logger.debug(f"Host snap {snap_name} has different channel, skipping")
+        raise IncompatibleSnapError(f"Host snap {snap_name} has different channel")
+
+    # find and inject base snap if exists
+    host_snap_base = host_snap_info.get("base", None)
+    if host_snap_base:
+        host_snap_base_info = get_host_snap_info(host_snap_base)
+        if host_snap_base_info.get("name", None):
+            inject_from_host(executor=executor, snap_name=host_snap_base, classic=False)
+
+    inject_from_host(executor=executor, snap_name=snap_name, classic=classic)
+
+
 def install_from_store(
-    *, executor: Executor, snap_name: str, channel: str, classic: bool
+    *,
+    executor: Executor,
+    snap_name: str,
+    channel: str,
+    classic: bool,
+    try_local: bool = True,
 ) -> None:
     """Install snap from store into target.
 
@@ -409,11 +449,37 @@ def install_from_store(
     :param snap_name: Name of snap to install.
     :param channel: Channel to install from.
     :param classic: Install in classic mode.
+    :param try_local: Try to install from local snap if available.
 
     :raises SnapInstallationError: on unexpected error.
     """
     # trim the `_name` suffix, if present
     snap_store_name = snap_name.split("_")[0]
+
+    if try_local:
+        logger.debug(
+            "Checking snap %r from host snapd (channel=%r, classic=%s).",
+            snap_name,
+            channel,
+            classic,
+        )
+
+        try:
+            _try_install_from_host(
+                executor=executor, snap_name=snap_name, channel=channel, classic=classic
+            )
+        except IncompatibleSnapError as error:
+            logger.debug(
+                "Failed to find snap %r from host snapd (channel=%r, classic=%s).",
+                snap_name,
+                channel,
+                classic,
+            )
+            logger.debug("Error: %s", error)
+        else:
+            logger.debug("Snap %r installed from host snapd.", snap_name)
+            return
+
     if snap_name == snap_store_name:
         logger.debug(
             "Installing snap %r from store (channel=%r, classic=%s).",

craft_providers/errors.py

@@ -130,3 +130,8 @@ def __init__(self) -> None:
             "see https://craft-providers.readthedocs.io/ for further reference."
         )
         super().__init__(brief=brief, resolution=resolution)
+
+
+@dataclasses.dataclass
+class IncompatibleSnapError(ProviderError, RuntimeError):
+    """Host snap is incompatible with the target."""

tests/integration/actions/test_snap_installer.py

@@ -138,6 +138,7 @@ def test_install_from_store_strict(core22_lxd_instance, installed_snap, caplog):
         snap_name="hello-world",
         channel="latest/stable",
         classic=False,
+        try_local=False,
     )
 
     core22_lxd_instance.execute_run(["test", "-f", "/snap/bin/hello-world"], check=True)
@@ -177,6 +178,7 @@ def test_install_from_store_classic(core22_lxd_instance, installed_snap, caplog)
         snap_name="charmcraft",
         channel="latest/stable",
         classic=True,
+        try_local=False,
     )
 
     core22_lxd_instance.execute_run(["test", "-f", "/snap/bin/charmcraft"], check=True)
@@ -216,6 +218,7 @@ def test_install_from_store_channel(core22_lxd_instance, installed_snap, caplog)
         snap_name="go",
         channel="1.15/stable",
         classic=True,
+        try_local=False,
     )
 
     proc = core22_lxd_instance.execute_run(
@@ -263,6 +266,7 @@ def test_install_from_store_snap_name_suffix(
         snap_name="hello-world_suffix",
         channel="latest/stable",
         classic=False,
+        try_local=False,
     )
 
     core22_lxd_instance.execute_run(["test", "-f", "/snap/bin/hello-world"], check=True)

tests/unit/actions/test_snap_installer.py

@@ -601,6 +601,7 @@ def test_install_from_store_strict(
         snap_name="test-name_suffix",
         classic=False,
         channel="test-chan",
+        try_local=False,
     )
 
     assert len(fake_process.calls) == 1
@@ -652,7 +653,11 @@ def test_install_from_store_classic(
     )
 
     snap_installer.install_from_store(
-        executor=fake_executor, snap_name="test-name", classic=True, channel="test-chan"
+        executor=fake_executor,
+        snap_name="test-name",
+        classic=True,
+        channel="test-chan",
+        try_local=False,
     )
 
     assert len(fake_process.calls) == 1
@@ -691,6 +696,7 @@ def test_refresh_from_store(
         snap_name="test-name",
         classic=False,
         channel="test-chan",
+        try_local=False,
     )
 
     assert len(fake_process.calls) == 1
@@ -741,6 +747,7 @@ def test_install_from_store_failure(
             snap_name="test-name",
             classic=True,
             channel="test-chan",
+            try_local=False,
         )
 
     assert exc_info.value == snap_installer.SnapInstallationError(
@@ -779,6 +786,7 @@ def test_install_from_store_trim_suffix(
         snap_name="test-name",
         classic=False,
         channel="test-chan",
+        try_local=False,
     )
 
     assert len(fake_process.calls) == 1