openrag/src/utils/container_utils.py
2025-10-07 11:32:04 -04:00

298 lines
11 KiB
Python

"""Utilities for detecting and working with container environments."""
import os
from pathlib import Path
def detect_container_environment() -> str | None:
"""Detect if running in a container and return the appropriate container type.
Returns:
'docker' if running in Docker, 'podman' if running in Podman, None otherwise.
"""
# Check for .dockerenv file (Docker)
if Path("/.dockerenv").exists():
return "docker"
# Check cgroup for container indicators
try:
with Path("/proc/self/cgroup").open() as f:
content = f.read()
if "docker" in content:
return "docker"
if "podman" in content:
return "podman"
except (FileNotFoundError, PermissionError):
pass
# Check environment variables (lowercase 'container' is the standard for Podman)
if os.getenv("container") == "podman": # noqa: SIM112
return "podman"
return None
def get_container_host() -> str | None:
"""Get the hostname to access host services from within a container.
Tries multiple methods to find the correct hostname:
1. host.containers.internal (Podman) or host.docker.internal (Docker)
2. Gateway IP from routing table (fallback for Linux)
Returns:
The hostname or IP to use, or None if not in a container.
"""
import socket
# Check if we're in a container first
container_type = detect_container_environment()
if not container_type:
return None
# Try container-specific hostnames first based on detected type
if container_type == "podman":
# Podman: try host.containers.internal first
try:
socket.getaddrinfo("host.containers.internal", None)
except socket.gaierror:
pass
else:
return "host.containers.internal"
# Fallback to host.docker.internal (for Podman Desktop on macOS)
try:
socket.getaddrinfo("host.docker.internal", None)
except socket.gaierror:
pass
else:
return "host.docker.internal"
else:
# Docker: try host.docker.internal first
try:
socket.getaddrinfo("host.docker.internal", None)
except socket.gaierror:
pass
else:
return "host.docker.internal"
# Fallback to host.containers.internal (unlikely but possible)
try:
socket.getaddrinfo("host.containers.internal", None)
except socket.gaierror:
pass
else:
return "host.containers.internal"
# Fallback: try to get gateway IP from routing table (Linux containers)
try:
with Path("/proc/net/route").open() as f:
for line in f:
fields = line.strip().split()
min_field_count = 3 # Minimum fields needed: interface, destination, gateway
if len(fields) >= min_field_count and fields[1] == "00000000": # Default route
# Gateway is in hex format (little-endian)
gateway_hex = fields[2]
# Convert hex to IP address
# The hex is in little-endian format, so we read it backwards in pairs
octets = [gateway_hex[i : i + 2] for i in range(0, 8, 2)]
return ".".join(str(int(octet, 16)) for octet in reversed(octets))
except (FileNotFoundError, PermissionError, IndexError, ValueError):
pass
return None
def transform_localhost_url(url: str) -> str:
"""Transform localhost URLs to container-accessible hosts when running in a container.
Automatically detects if running inside a container and finds the appropriate host
address to replace localhost/127.0.0.1. Tries in order:
- host.docker.internal (if resolvable)
- host.containers.internal (if resolvable)
- Gateway IP from routing table (fallback)
Args:
url: The original URL
Returns:
Transformed URL with container-accessible host if applicable, otherwise the original URL.
Example:
>>> transform_localhost_url("http://localhost:5001")
# Returns "http://host.docker.internal:5001" if running in Docker and hostname resolves
# Returns "http://172.17.0.1:5001" if running in Docker on Linux (gateway IP fallback)
# Returns "http://localhost:5001" if not in a container
"""
container_host = get_container_host()
if not container_host:
return url
# Replace localhost and 127.0.0.1 with the container host
localhost_patterns = ["localhost", "127.0.0.1"]
for pattern in localhost_patterns:
if pattern in url:
return url.replace(pattern, container_host)
return url
def guess_host_ip_for_containers(logger=None) -> str:
"""Best-effort detection of a host IP reachable from container networks.
The logic mirrors what the TUI uses when launching docling-serve so that
both CLI and API use consistent addresses. Preference order:
1. Docker/Podman compose networks (ended with ``_default``)
2. Networks with active containers
3. Any discovered bridge or CNI gateway interfaces
Args:
logger: Optional logger to emit diagnostics; falls back to module logger.
Returns:
The most appropriate host IP address if discovered, otherwise ``"127.0.0.1"``.
"""
import json
import logging
import re
import shutil
import socket
import subprocess
log = logger or logging.getLogger(__name__)
def can_bind_to_address(ip_addr: str) -> bool:
"""Test if we can bind to the given IP address."""
try:
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((ip_addr, 0)) # Port 0 = let OS choose a free port
return True
except (OSError, socket.error) as e:
log.debug("Cannot bind to %s: %s", ip_addr, e)
return False
def run(cmd, timeout=2, text=True):
return subprocess.run(cmd, capture_output=True, text=text, timeout=timeout)
gateways: list[str] = []
compose_gateways: list[str] = []
active_gateways: list[str] = []
# ---- Docker networks
if shutil.which("docker"):
try:
ls = run(["docker", "network", "ls", "--format", "{{.Name}}"])
if ls.returncode == 0:
for name in filter(None, ls.stdout.splitlines()):
try:
insp = run(["docker", "network", "inspect", name, "--format", "{{json .}}"])
if insp.returncode == 0 and insp.stdout.strip():
payload = insp.stdout.strip()
nw = json.loads(payload)[0] if payload.startswith("[") else json.loads(payload)
ipam = nw.get("IPAM", {})
containers = nw.get("Containers", {})
for cfg in ipam.get("Config", []) or []:
gw = cfg.get("Gateway")
if not gw:
continue
if name.endswith("_default"):
compose_gateways.append(gw)
elif len(containers) > 0:
active_gateways.append(gw)
else:
gateways.append(gw)
except Exception:
continue
except Exception:
pass
# ---- Podman networks
if shutil.which("podman"):
try:
ls = run(["podman", "network", "ls", "--format", "json"])
if ls.returncode == 0 and ls.stdout.strip():
for net in json.loads(ls.stdout):
name = net.get("name") or net.get("Name")
if not name:
continue
try:
insp = run(["podman", "network", "inspect", name, "--format", "json"])
if insp.returncode == 0 and insp.stdout.strip():
arr = json.loads(insp.stdout)
for item in (arr if isinstance(arr, list) else [arr]):
for sn in item.get("subnets", []) or []:
gw = sn.get("gateway")
if not gw:
continue
if name.endswith("_default") or "_" in name:
compose_gateways.append(gw)
else:
gateways.append(gw)
except Exception:
continue
except Exception:
pass
# ---- Host bridge interfaces
if not gateways and not compose_gateways and not active_gateways:
try:
if shutil.which("ip"):
show = run(["ip", "-o", "-4", "addr", "show"])
if show.returncode == 0:
for line in show.stdout.splitlines():
match = re.search(r"^\d+:\s+([\w_.:-]+)\s+.*\binet\s+(\d+\.\d+\.\d+\.\d+)/", line)
if not match:
continue
ifname, ip_addr = match.group(1), match.group(2)
if ifname == "docker0" or ifname.startswith(("br-", "cni")):
gateways.append(ip_addr)
elif shutil.which("ifconfig"):
show = run(["ifconfig"])
for block in show.stdout.split("\n\n"):
if any(block.strip().startswith(n) for n in ("docker0", "cni", "br-")):
match = re.search(r"inet (?:addr:)?(\d+\.\d+\.\d+\.\d+)", block)
if match:
gateways.append(match.group(1))
except Exception:
pass
seen: set[str] = set()
ordered_candidates: list[str] = []
for collection in (compose_gateways, active_gateways, gateways):
for ip_addr in collection:
if ip_addr not in seen:
ordered_candidates.append(ip_addr)
seen.add(ip_addr)
if ordered_candidates:
if len(ordered_candidates) > 1:
log.info(
"Container-reachable host IP candidates: %s",
", ".join(ordered_candidates),
)
# Try each candidate and return the first one we can bind to
for ip_addr in ordered_candidates:
if can_bind_to_address(ip_addr):
if len(ordered_candidates) > 1:
log.info("Selected bindable host IP: %s", ip_addr)
else:
log.info("Container-reachable host IP: %s", ip_addr)
return ip_addr
log.debug("Skipping %s (cannot bind)", ip_addr)
# None of the candidates were bindable, fall back to 127.0.0.1
log.warning(
"None of the discovered IPs (%s) can be bound; falling back to 127.0.0.1",
", ".join(ordered_candidates),
)
return "127.0.0.1"
log.warning(
"No container bridge IP found. For rootless Podman (slirp4netns) there may be no host bridge; publish ports or use 10.0.2.2 from the container."
)
return "127.0.0.1"