attach to pty with pexpect

langchain/utilities/docker/pexpect_exec.py

@@ -0,0 +1,32 @@
+import pexpect
+
+def interact_with_python_shell(child: pexpect.spawn, **kwargs) -> str:
+    """Interact with a Python shell running in a pexpect spawn instance."""
+    try:
+        child.expect(">>>", **kwargs)
+    except pexpect.exceptions.TIMEOUT:
+        print("no data")
+        return child.before.strip()
+    buf = ""
+    max_reads=5
+    read_cnt=0
+    while True:
+        if read_cnt > max_reads:
+            print("reached max depth")
+            break
+        try:
+            child.expect("\n>>>", **kwargs)
+            result = child.before.strip()
+            if len(result) > 0:
+                buf += result + "\n"
+        except pexpect.exceptions.TIMEOUT:
+            # The child process is still running, but it's not outputting anything.
+            # Wait a bit and try again.
+            #TODO: add trial times before exit
+            read_cnt += 1
+            continue
+        except pexpect.exceptions.EOF:
+            # The child process has exited.
+            print("EOF")
+            break
+    return buf