fix: Run backup/restore on host via nsenter for Python venv compatibility

Matthias Nott

2026-02-21 7300351bb9fb147f4de81a60423c4561a4924c21

 app/ops_runner.py
..
..
@@ -10,58 +10,31 @@
10
10
 _DEFAULT_TIMEOUT = 300
11
11
 _BACKUP_TIMEOUT = 3600
12
12
 
13
+# nsenter via Docker: run commands on the host from inside the container.
14
+# Required because ops backup/restore delegate to host Python venvs (3.12)
15
+# that are incompatible with the container's Python (3.11).
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+_NSENTER_PREFIX = [
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+    "docker", "run", "--rm", "-i",
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+    "--privileged", "--pid=host", "--network=host",
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+    "alpine",
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+    "nsenter", "-t", "1", "-m", "-u", "-i", "-n", "-p", "--",
21
+]
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+
23
+
24
+# ---------------------------------------------------------------------------
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+# In-container execution (status, disk, health, docker commands)
26
+# ---------------------------------------------------------------------------
13
27
 
14
28
 async def run_ops(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> dict:
15
-    """
16
-    Run the ops CLI with the given arguments and capture output.
17
-    Returns {"success": bool, "output": str, "error": str}.
18
-    """
19
-    try:
20
-        proc = await asyncio.create_subprocess_exec(
21
-            OPS_CLI,
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-            *args,
23
-            stdout=asyncio.subprocess.PIPE,
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-            stderr=asyncio.subprocess.PIPE,
25
-        )
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-        try:
27
-            stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=timeout)
28
-        except asyncio.TimeoutError:
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-            proc.kill()
30
-            await proc.communicate()
31
-            return {
32
-                "success": False,
33
-                "output": "",
34
-                "error": f"Command timed out after {timeout}s",
35
-            }
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-
37
-        return {
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-            "success": proc.returncode == 0,
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-            "output": stdout.decode("utf-8", errors="replace"),
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-            "error": stderr.decode("utf-8", errors="replace"),
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-        }
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-    except FileNotFoundError:
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-        return {
44
-            "success": False,
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-            "output": "",
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-            "error": f"ops CLI not found at {OPS_CLI}",
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-        }
48
-    except Exception as exc:
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-        return {
50
-            "success": False,
51
-            "output": "",
52
-            "error": str(exc),
53
-        }
29
+    """Run the ops CLI inside the container."""
30
+    return await _run_exec([OPS_CLI] + args, timeout=timeout)
54
31
 
55
32
 
56
33
 async def run_ops_json(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> dict:
57
-    """
58
-    Run the ops CLI with --json appended and return the parsed JSON output.
59
-    Returns {"success": bool, "data": ..., "error": str}.
60
-    """
34
+    """Run the ops CLI with --json and return parsed JSON."""
61
35
     result = await run_ops(args + ["--json"], timeout=timeout)
62
36
     if not result["success"]:
63
37
         return {"success": False, "data": None, "error": result["error"] or result["output"]}
64
-
65
38
     try:
66
39
         data = json.loads(result["output"])
67
40
         return {"success": True, "data": data, "error": ""}
..
..
@@ -69,95 +42,48 @@
69
42
         return {
70
43
             "success": False,
71
44
             "data": None,
72
-            "error": f"Failed to parse JSON output: {exc}\nRaw output: {result['output'][:500]}",
45
+            "error": f"Failed to parse JSON: {exc}\nRaw: {result['output'][:500]}",
73
46
         }
74
47
 
75
48
 
76
49
 async def stream_ops(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> AsyncGenerator[str, None]:
77
-    """
78
-    Async generator that yields lines of stdout from the ops CLI.
79
-    Also yields stderr lines prefixed with '[stderr] '.
80
-    """
81
-    try:
82
-        proc = await asyncio.create_subprocess_exec(
83
-            OPS_CLI,
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-            *args,
85
-            stdout=asyncio.subprocess.PIPE,
86
-            stderr=asyncio.subprocess.PIPE,
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-        )
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-    except FileNotFoundError:
89
-        yield f"[error] ops CLI not found at {OPS_CLI}"
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-        return
91
-    except Exception as exc:
92
-        yield f"[error] Failed to start process: {exc}"
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-        return
94
-
95
-    async def _read_stream(stream: asyncio.StreamReader, prefix: str = "") -> AsyncGenerator[str, None]:
96
-        while True:
97
-            try:
98
-                line = await asyncio.wait_for(stream.readline(), timeout=timeout)
99
-            except asyncio.TimeoutError:
100
-                yield f"{prefix}[timeout] Command exceeded {timeout}s"
101
-                break
102
-            if not line:
103
-                break
104
-            yield prefix + line.decode("utf-8", errors="replace").rstrip("\n")
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-
106
-    # Interleave stdout and stderr
107
-    stdout_gen = _read_stream(proc.stdout)
108
-    stderr_gen = _read_stream(proc.stderr, prefix="[stderr] ")
109
-
110
-    stdout_done = False
111
-    stderr_done = False
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-
113
-    stdout_iter = stdout_gen.__aiter__()
114
-    stderr_iter = stderr_gen.__aiter__()
115
-
116
-    pending_stdout: asyncio.Task | None = None
117
-    pending_stderr: asyncio.Task | None = None
118
-
119
-    async def _next(it):
120
-        try:
121
-            return await it.__anext__()
122
-        except StopAsyncIteration:
123
-            return None
124
-
125
-    pending_stdout = asyncio.create_task(_next(stdout_iter))
126
-    pending_stderr = asyncio.create_task(_next(stderr_iter))
127
-
128
-    while not (stdout_done and stderr_done):
129
-        done, _ = await asyncio.wait(
130
-            [t for t in [pending_stdout, pending_stderr] if t is not None],
131
-            return_when=asyncio.FIRST_COMPLETED,
132
-        )
133
-
134
-        for task in done:
135
-            val = task.result()
136
-            if task is pending_stdout:
137
-                if val is None:
138
-                    stdout_done = True
139
-                    pending_stdout = None
140
-                else:
141
-                    yield val
142
-                    pending_stdout = asyncio.create_task(_next(stdout_iter))
143
-            elif task is pending_stderr:
144
-                if val is None:
145
-                    stderr_done = True
146
-                    pending_stderr = None
147
-                else:
148
-                    yield val
149
-                    pending_stderr = asyncio.create_task(_next(stderr_iter))
150
-
151
-    await proc.wait()
50
+    """Stream ops CLI output (in-container)."""
51
+    async for line in _stream_exec([OPS_CLI] + args, timeout=timeout):
52
+        yield line
152
53
 
153
54
 
154
-async def run_command(
155
-    args: list[str], timeout: int = _DEFAULT_TIMEOUT
156
-) -> dict:
157
-    """
158
-    Generic command runner (non-ops). Accepts a full argv list.
159
-    Returns {"success": bool, "output": str, "error": str}.
160
-    """
55
+async def run_command(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> dict:
56
+    """Generic command runner (in-container)."""
57
+    return await _run_exec(args, timeout=timeout)
58
+
59
+
60
+async def stream_command(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> AsyncGenerator[str, None]:
61
+    """Stream generic command output (in-container)."""
62
+    async for line in _stream_exec(args, timeout=timeout):
63
+        yield line
64
+
65
+
66
+# ---------------------------------------------------------------------------
67
+# Host execution (backup, restore — needs host Python venvs)
68
+# ---------------------------------------------------------------------------
69
+
70
+async def run_ops_host(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> dict:
71
+    """Run the ops CLI on the host via nsenter."""
72
+    return await _run_exec(_NSENTER_PREFIX + [OPS_CLI] + args, timeout=timeout)
73
+
74
+
75
+async def stream_ops_host(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> AsyncGenerator[str, None]:
76
+    """Stream ops CLI output from the host via nsenter."""
77
+    async for line in _stream_exec(_NSENTER_PREFIX + [OPS_CLI] + args, timeout=timeout):
78
+        yield line
79
+
80
+
81
+# ---------------------------------------------------------------------------
82
+# Internal helpers
83
+# ---------------------------------------------------------------------------
84
+
85
+async def _run_exec(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> dict:
86
+    """Execute a command and capture output."""
161
87
     try:
162
88
         proc = await asyncio.create_subprocess_exec(
163
89
             *args,
..
..
@@ -169,11 +95,7 @@
169
95
         except asyncio.TimeoutError:
170
96
             proc.kill()
171
97
             await proc.communicate()
172
-            return {
173
-                "success": False,
174
-                "output": "",
175
-                "error": f"Command timed out after {timeout}s",
176
-            }
98
+            return {"success": False, "output": "", "error": f"Command timed out after {timeout}s"}
177
99
 
178
100
         return {
179
101
             "success": proc.returncode == 0,
..
..
@@ -186,12 +108,8 @@
186
108
         return {"success": False, "output": "", "error": str(exc)}
187
109
 
188
110
 
189
-async def stream_command(
190
-    args: list[str], timeout: int = _DEFAULT_TIMEOUT
191
-) -> AsyncGenerator[str, None]:
192
-    """
193
-    Async generator that yields lines of stdout for an arbitrary command.
194
-    """
111
+async def _stream_exec(args: list[str], timeout: int = _DEFAULT_TIMEOUT) -> AsyncGenerator[str, None]:
112
+    """Execute a command and yield interleaved stdout/stderr lines."""
195
113
     try:
196
114
         proc = await asyncio.create_subprocess_exec(
197
115
             *args,
..
..
@@ -202,24 +120,56 @@
202
120
         yield f"[error] Executable not found: {exc}"
203
121
         return
204
122
     except Exception as exc:
205
-        yield f"[error] {exc}"
123
+        yield f"[error] Failed to start process: {exc}"
206
124
         return
207
125
 
208
-    while True:
209
-        try:
210
-            line = await asyncio.wait_for(proc.stdout.readline(), timeout=timeout)
211
-        except asyncio.TimeoutError:
212
-            yield f"[timeout] Command exceeded {timeout}s"
213
-            proc.kill()
214
-            break
215
-        if not line:
216
-            break
217
-        yield line.decode("utf-8", errors="replace").rstrip("\n")
126
+    async def _readline(stream, prefix=""):
127
+        while True:
128
+            try:
129
+                line = await asyncio.wait_for(stream.readline(), timeout=timeout)
130
+            except asyncio.TimeoutError:
131
+                yield f"{prefix}[timeout] Command exceeded {timeout}s"
132
+                break
133
+            if not line:
134
+                break
135
+            yield prefix + line.decode("utf-8", errors="replace").rstrip("\n")
218
136
 
219
-    # Flush stderr as trailing info
220
-    stderr_data = await proc.stderr.read()
221
-    if stderr_data:
222
-        for ln in stderr_data.decode("utf-8", errors="replace").splitlines():
223
-            yield f"[stderr] {ln}"
137
+    stdout_gen = _readline(proc.stdout).__aiter__()
138
+    stderr_gen = _readline(proc.stderr, "[stderr] ").__aiter__()
139
+
140
+    stdout_done = stderr_done = False
141
+    pending_out = pending_err = None
142
+
143
+    async def _next(it):
144
+        try:
145
+            return await it.__anext__()
146
+        except StopAsyncIteration:
147
+            return None
148
+
149
+    pending_out = asyncio.create_task(_next(stdout_gen))
150
+    pending_err = asyncio.create_task(_next(stderr_gen))
151
+
152
+    while not (stdout_done and stderr_done):
153
+        tasks = [t for t in (pending_out, pending_err) if t is not None]
154
+        if not tasks:
155
+            break
156
+        done, _ = await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
157
+
158
+        for task in done:
159
+            val = task.result()
160
+            if task is pending_out:
161
+                if val is None:
162
+                    stdout_done = True
163
+                    pending_out = None
164
+                else:
165
+                    yield val
166
+                    pending_out = asyncio.create_task(_next(stdout_gen))
167
+            elif task is pending_err:
168
+                if val is None:
169
+                    stderr_done = True
170
+                    pending_err = None
171
+                else:
172
+                    yield val
173
+                    pending_err = asyncio.create_task(_next(stderr_gen))
224
174
 
225
175
     await proc.wait()