IO updates (#5)

* Always log to stderr. Valid uses of the CLI will be watching for stdout and we don't want to pollute it with logs.
* Allow overriding stdout and stderr in shell functions. Sometimes we don't care about the output at all.
* Defer some imports to better enable individual tool use.

src/mads/build/shell.py

@@ -60,27 +60,33 @@ def _stream_process(cmd, **kwargs):
         cmd,
         encoding="utf-8",
         stdin=subprocess.PIPE if "input" in kwargs else subprocess.DEVNULL,
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
+        stdout=kwargs.get("stdout", subprocess.PIPE),
+        stderr=kwargs.get("stderr", subprocess.PIPE),
         shell=True,
         cwd=kwargs.get("cwd"),
     ) as process:
-        stdout = ""
-        stderr = ""
 
-        if kwargs.get("input"):
-            process.stdin.write(kwargs["input"])
-            process.stdin.close()
+        # Configure the IO/streams
+        if process.stdin:
+            if kwargs.get("input"):
+                process.stdin.write(kwargs["input"])
+                process.stdin.close()
 
         # Don't block on stdout/stderr
-        os.set_blocking(process.stdout.fileno(), False)
-        os.set_blocking(process.stderr.fileno(), False)
+        if process.stdout:
+            os.set_blocking(process.stdout.fileno(), False)
+        if process.stderr:
+            os.set_blocking(process.stderr.fileno(), False)
+
+        # Collect the output streams
+        stdout = ""
+        stderr = ""
 
         def communicate(proc):
             """Read stdin and stdout from a process as streams."""
             nonlocal stdout, stderr
 
-            outputs = [proc.stdout, proc.stderr]
+            outputs = list(filter(None, [proc.stdout, proc.stderr]))
 
             # Select will return a list of only files ready to read from
             ready, _, _ = select.select(outputs, [], [], 0.0001)

src/mads/environ/git.py

@@ -6,13 +6,14 @@
 
 from pydantic_settings import BaseSettings
 
-from mads.build.shell import shell
 
 NOT_GIT = {"message": "[This does not appear to be a git project]"}
 
 
 @cache
 def git_config_source() -> dict[str, str]:
+    from mads.build.shell import shell
+
     cwd = Path(".git")
 
     # If the git cache is populated, .git is actually a file pointing to the

src/mads/environ/resources.py

@@ -6,8 +6,6 @@
 from pydantic import Field
 from pydantic_settings import BaseSettings
 
-from mads.build import log, shell
-
 
 class Resources(BaseSettings):
     """Get information about the current system we're running in."""
@@ -39,6 +37,8 @@ class Resources(BaseSettings):
     def enable_swap(self):
         """Enable swap memory."""
 
+        from mads.build import log, shell
+
         if self.swap_memory > 0:
             log.info("Swap memory is already enabled.")
             return True