Set channel priority to strict, print config info

Fixes #359, fixes #659.

conda-store-server/conda_store_server/action/generate_lockfile.py

@@ -1,5 +1,7 @@
 import json
+import os
 import pathlib
+import subprocess
 import typing
 
 import yaml
@@ -13,19 +15,39 @@ def action_solve_lockfile(
     conda_command: str,
     specification: schema.CondaSpecification,
     platforms: typing.List[str] = [conda_utils.conda_platform()],
+    # https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-channels.html
+    conda_flags: str = "--strict-channel-priority",
 ):
     environment_filename = pathlib.Path.cwd() / "environment.yaml"
     lockfile_filename = pathlib.Path.cwd() / "conda-lock.yaml"
 
     with environment_filename.open("w") as f:
         json.dump(specification.dict(), f)
 
-    run_lock(
-        environment_files=[environment_filename],
-        platforms=platforms,
-        lockfile_path=lockfile_filename,
-        conda_exe=conda_command,
-    )
+    def print_cmd(cmd):
+        print(f"Running command: {' '.join(cmd)}")
+        print(subprocess.check_output(cmd, stderr=subprocess.STDOUT, encoding="utf-8"))
+
+    # The info command can be used with either mamba or conda
+    print_cmd([conda_command, "info"])
+    # The config command is not supported by mamba
+    print_cmd(["conda", "config", "--show"])
+    print_cmd(["conda", "config", "--show-sources"])
+
+    # CONDA_FLAGS is used by conda-lock in conda_solver.solve_specs_for_arch
+    try:
+        conda_flags_name = "CONDA_FLAGS"
+        print(f"{conda_flags_name}={conda_flags}")
+        os.environ[conda_flags_name] = conda_flags
+
+        run_lock(
+            environment_files=[environment_filename],
+            platforms=platforms,
+            lockfile_path=lockfile_filename,
+            conda_exe=conda_command,
+        )
+    finally:
+        os.environ.pop(conda_flags_name, None)
 
     with lockfile_filename.open() as f:
         return yaml.safe_load(f)

conda-store-server/tests/test_actions.py

@@ -69,6 +69,29 @@ def test_solve_lockfile(conda_store, specification, request):
     assert len(context.result["package"]) != 0
 
 
+def test_solve_lockfile_valid_conda_flags(conda_store, simple_specification):
+    context = action.action_solve_lockfile(
+        conda_command=conda_store.conda_command,
+        specification=simple_specification,
+        platforms=[conda_utils.conda_platform()],
+        conda_flags="--strict-channel-priority",
+    )
+    assert len(context.result["package"]) != 0
+
+
+# Checks that conda_flags is used by conda-lock
+def test_solve_lockfile_invalid_conda_flags(conda_store, simple_specification):
+    with pytest.raises(Exception, match=(
+        r"Command.*--this-is-invalid.*returned non-zero exit status"
+    )):
+        action.action_solve_lockfile(
+            conda_command=conda_store.conda_command,
+            specification=simple_specification,
+            platforms=[conda_utils.conda_platform()],
+            conda_flags="--this-is-invalid",
+        )
+
+
 @pytest.mark.parametrize(
     "specification",
     [