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dephealth

SDK for monitoring microservice dependencies via Prometheus metrics.

Features

• Automatic health checking for dependencies (PostgreSQL, MySQL, Redis, RabbitMQ, Kafka, HTTP, gRPC, TCP, LDAP)
• Prometheus metrics export: app_dependency_health (Gauge 0/1), app_dependency_latency_seconds (Histogram), app_dependency_status (enum), app_dependency_status_detail (info)
• Async architecture built on asyncio
• FastAPI integration (middleware, lifespan, endpoints)
• Connection pool support (preferred) and standalone checks

Installation

# Basic installation
pip install dephealth

# With specific checkers
pip install dephealth[postgres,redis]

# All checkers + FastAPI
pip install dephealth[all]

Quick Start

Standalone

from dephealth import DepHealth

dh = DepHealth()
dh.add("postgres", url="postgresql://user:pass@localhost:5432/mydb")
dh.add("redis", url="redis://localhost:6379")

await dh.start()
# Metrics are available via prometheus_client
await dh.stop()

FastAPI

from fastapi import FastAPI
from dephealth_fastapi import DepHealthFastAPI

app = FastAPI()
dh = DepHealthFastAPI(app)
dh.add("postgres", url="postgresql://user:pass@localhost:5432/mydb")

Dynamic Endpoints

Add, remove, or replace monitored endpoints at runtime on a running instance (v0.6.0+):

from dephealth import DependencyType, Endpoint
from dephealth.checks.http import HTTPChecker

# After dh.start()...

# Add a new endpoint
await dh.add_endpoint(
    "api-backend",
    DependencyType.HTTP,
    True,
    Endpoint(host="backend-2.svc", port="8080"),
    HTTPChecker(),
)

# Remove an endpoint (cancels check task, deletes metrics)
await dh.remove_endpoint("api-backend", "backend-2.svc", "8080")

# Replace an endpoint atomically
await dh.update_endpoint(
    "api-backend",
    "backend-1.svc", "8080",
    Endpoint(host="backend-3.svc", port="8080"),
    HTTPChecker(),
)

Synchronous variants are available: add_endpoint_sync(), remove_endpoint_sync(), update_endpoint_sync().

See migration guide for details.

Health Details

details = dh.health_details()
for key, ep in details.items():
    print(f"{key}: healthy={ep.healthy} status={ep.status} "
          f"latency={ep.latency_millis():.1f}ms")

Configuration

Supported Dependencies

LDAP Checker

LDAP health checker supports four check methods and multiple TLS modes:

from dephealth.checks.ldap import LdapChecker, LdapCheckMethod, LdapSearchScope

# RootDSE check (default)
ldap_checker = LdapChecker(check_method=LdapCheckMethod.ROOT_DSE)

# Simple bind with credentials
ldap_checker = LdapChecker(
    check_method=LdapCheckMethod.SIMPLE_BIND,
    bind_dn="cn=monitor,dc=corp,dc=com",
    bind_password="secret",
    use_tls=True,
)

# Search with StartTLS
ldap_checker = LdapChecker(
    check_method=LdapCheckMethod.SEARCH,
    base_dn="dc=example,dc=com",
    search_filter="(objectClass=organizationalUnit)",
    search_scope=LdapSearchScope.ONE,
    start_tls=True,
)

Check methods: ANONYMOUS_BIND, SIMPLE_BIND, ROOT_DSE (default), SEARCH.

Authentication

HTTP and gRPC checkers support Bearer token, Basic Auth, and custom headers/metadata:

http_check("secure-api",
    url="http://api.svc:8080",
    critical=True,
    bearer_token="eyJhbG...",
)

grpc_check("grpc-backend",
    host="backend.svc",
    port=9090,
    critical=True,
    bearer_token="eyJhbG...",
)

See authentication guide for all options.

Documentation

Full documentation is available in the docs/ directory.

License

Apache License 2.0 — see LICENSE.