dashboard: fix subprocesses blocking the event loop (#5772)

* dashboard: fix subprocesses blocking the event loop

- break apart the util module
- adds a new util to run subprocesses with asyncio

* take a list

esphome/dashboard/settings.py

@@ -10,7 +10,7 @@ from esphome.helpers import get_bool_env
 from esphome.storage_json import ext_storage_path
 
 from .entries import DashboardEntry
-from .util import password_hash
+from .util.password import password_hash
 
 
 class DashboardSettings:

esphome/dashboard/status/ping.py

@@ -7,22 +7,15 @@ from typing import cast
 from ..core import DASHBOARD
 from ..entries import DashboardEntry
 from ..core import list_dashboard_entries
-from ..util import chunked
+from ..util.itertools import chunked
+from ..util.subprocess import async_system_command_status
 
 
 async def _async_ping_host(host: str) -> bool:
     """Ping a host."""
-    ping_command = ["ping", "-n" if os.name == "nt" else "-c", "1"]
-    process = await asyncio.create_subprocess_exec(
-        *ping_command,
-        host,
-        stdin=asyncio.subprocess.DEVNULL,
-        stdout=asyncio.subprocess.DEVNULL,
-        stderr=asyncio.subprocess.DEVNULL,
-        close_fds=False,
+    return await async_system_command_status(
+        ["ping", "-n" if os.name == "nt" else "-c", "1", host]
     )
-    await process.wait()
-    return process.returncode == 0
 
 
 class PingStatus:

esphome/dashboard/util.py

@@ -1,52 +0,0 @@
-import hashlib
-import unicodedata
-from collections.abc import Iterable
-from functools import partial
-from itertools import islice
-from typing import Any
-
-from esphome.const import ALLOWED_NAME_CHARS
-
-
-def password_hash(password: str) -> bytes:
-    """Create a hash of a password to transform it to a fixed-length digest.
-
-    Note this is not meant for secure storage, but for securely comparing passwords.
-    """
-    return hashlib.sha256(password.encode()).digest()
-
-
-def strip_accents(value):
-    return "".join(
-        c
-        for c in unicodedata.normalize("NFD", str(value))
-        if unicodedata.category(c) != "Mn"
-    )
-
-
-def friendly_name_slugify(value):
-    value = (
-        strip_accents(value)
-        .lower()
-        .replace(" ", "-")
-        .replace("_", "-")
-        .replace("--", "-")
-        .strip("-")
-    )
-    return "".join(c for c in value if c in ALLOWED_NAME_CHARS)
-
-
-def take(take_num: int, iterable: Iterable) -> list[Any]:
-    """Return first n items of the iterable as a list.
-
-    From itertools recipes
-    """
-    return list(islice(iterable, take_num))
-
-
-def chunked(iterable: Iterable, chunked_num: int) -> Iterable[Any]:
-    """Break *iterable* into lists of length *n*.
-
-    From more-itertools
-    """
-    return iter(partial(take, chunked_num, iter(iterable)), [])

esphome/dashboard/util/itertools.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+from collections.abc import Iterable
+from functools import partial
+from itertools import islice
+from typing import Any
+
+
+def take(take_num: int, iterable: Iterable) -> list[Any]:
+    """Return first n items of the iterable as a list.
+
+    From itertools recipes
+    """
+    return list(islice(iterable, take_num))
+
+
+def chunked(iterable: Iterable, chunked_num: int) -> Iterable[Any]:
+    """Break *iterable* into lists of length *n*.
+
+    From more-itertools
+    """
+    return iter(partial(take, chunked_num, iter(iterable)), [])

esphome/dashboard/util/password.py

@@ -0,0 +1,11 @@
+from __future__ import annotations
+
+import hashlib
+
+
+def password_hash(password: str) -> bytes:
+    """Create a hash of a password to transform it to a fixed-length digest.
+
+    Note this is not meant for secure storage, but for securely comparing passwords.
+    """
+    return hashlib.sha256(password.encode()).digest()

esphome/dashboard/util/subprocess.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import asyncio
+from collections.abc import Iterable
+
+
+async def async_system_command_status(command: Iterable[str]) -> bool:
+    """Run a system command checking only the status."""
+    process = await asyncio.create_subprocess_exec(
+        *command,
+        stdin=asyncio.subprocess.DEVNULL,
+        stdout=asyncio.subprocess.DEVNULL,
+        stderr=asyncio.subprocess.DEVNULL,
+        close_fds=False,
+    )
+    await process.wait()
+    return process.returncode == 0
+
+
+async def async_run_system_command(command: Iterable[str]) -> tuple[bool, bytes, bytes]:
+    """Run a system command and return a tuple of returncode, stdout, stderr."""
+    process = await asyncio.create_subprocess_exec(
+        *command,
+        stdin=asyncio.subprocess.DEVNULL,
+        stdout=asyncio.subprocess.PIPE,
+        stderr=asyncio.subprocess.PIPE,
+        close_fds=False,
+    )
+    stdout, stderr = await process.communicate()
+    await process.wait()
+    return process.returncode, stdout, stderr

esphome/dashboard/util/text.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+import unicodedata
+
+from esphome.const import ALLOWED_NAME_CHARS
+
+
+def strip_accents(value):
+    return "".join(
+        c
+        for c in unicodedata.normalize("NFD", str(value))
+        if unicodedata.category(c) != "Mn"
+    )
+
+
+def friendly_name_slugify(value):
+    value = (
+        strip_accents(value)
+        .lower()
+        .replace(" ", "-")
+        .replace("_", "-")
+        .replace("--", "-")
+        .strip("-")
+    )
+    return "".join(c for c in value if c in ALLOWED_NAME_CHARS)

esphome/dashboard/web_server.py

@@ -31,13 +31,14 @@ import yaml
 from tornado.log import access_log
 
 from esphome import const, platformio_api, yaml_util
-from esphome.helpers import get_bool_env, mkdir_p, run_system_command
+from esphome.helpers import get_bool_env, mkdir_p
 from esphome.storage_json import StorageJSON, ext_storage_path, trash_storage_path
 from esphome.util import get_serial_ports, shlex_quote
 
 from .core import DASHBOARD, list_dashboard_entries
 from .entries import DashboardEntry
-from .util import friendly_name_slugify
+from .util.text import friendly_name_slugify
+from .util.subprocess import async_run_system_command
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -522,7 +523,7 @@ class DownloadListRequestHandler(BaseHandler):
 class DownloadBinaryRequestHandler(BaseHandler):
     @authenticated
     @bind_config
-    def get(self, configuration=None):
+    async def get(self, configuration=None):
         compressed = self.get_argument("compressed", "0") == "1"
 
         storage_path = ext_storage_path(configuration)
@@ -548,7 +549,7 @@ class DownloadBinaryRequestHandler(BaseHandler):
 
         if not Path(path).is_file():
             args = ["esphome", "idedata", settings.rel_path(configuration)]
-            rc, stdout, _ = run_system_command(*args)
+            rc, stdout, _ = await async_run_system_command(args)
 
             if rc != 0:
                 self.send_error(404 if rc == 2 else 500)
@@ -902,7 +903,7 @@ SafeLoaderIgnoreUnknown.add_constructor(
 class JsonConfigRequestHandler(BaseHandler):
     @authenticated
     @bind_config
-    def get(self, configuration=None):
+    async def get(self, configuration=None):
         filename = settings.rel_path(configuration)
         if not os.path.isfile(filename):
             self.send_error(404)
@@ -910,7 +911,7 @@ class JsonConfigRequestHandler(BaseHandler):
 
         args = ["esphome", "config", filename, "--show-secrets"]
 
-        rc, stdout, _ = run_system_command(*args)
+        rc, stdout, _ = await async_run_system_command(args)
 
         if rc != 0:
             self.send_error(422)