File size: 4,644 Bytes
2021f39 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 | #!/usr/bin/env python3
"""
Graph memory service with optional Neo4j, in-memory fallback.
Endpoints:
- GET /health
- POST /upsert_nodes {nodes:[{id, labels, props}]}
- POST /upsert_edges {edges:[{src, dst, type, props}]}
- POST /neighbors {id, depth}
"""
import os
from typing import Dict, Any, List, Set
from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from prometheus_client import Counter, Histogram, make_asgi_app
import uvicorn
PORT = int(os.getenv("PORT", "7011"))
# In-memory graph
NODES: Dict[str, Dict[str, Any]] = {}
EDGES: List[Dict[str, Any]] = []
ADJ: Dict[str, Set[str]] = {}
app = FastAPI(title="Nova Graph Memory", version="0.1.0")
app.add_middleware(
CORSMiddleware,
allow_origins=["*"],
allow_credentials=True,
allow_methods=["*"],
allow_headers=["*"],
)
REQUESTS = Counter("graph_requests_total", "Graph service requests", ["route"])
LATENCY = Histogram("graph_request_latency_seconds", "Latency", ["route"])
@app.get("/health")
def health():
REQUESTS.labels(route="health").inc()
return {"status": "ok", "port": PORT}
@app.post("/upsert_nodes")
async def upsert_nodes(req: Request) -> JSONResponse:
with LATENCY.labels(route="upsert_nodes").time():
REQUESTS.labels(route="upsert_nodes").inc()
body = await req.json()
nodes = body.get("nodes", [])
# Optional Neo4j mirror
neo_ok = False
try:
import os as _os
from neo4j import GraphDatabase # type: ignore
uri = _os.getenv("NEO4J_URI")
if uri:
driver = GraphDatabase.driver(uri, auth=(_os.getenv("NEO4J_USER", "neo4j"), _os.getenv("NEO4J_PASSWORD", "neo4j")))
neo_ok = True
except Exception:
driver = None
for n in nodes:
nid = str(n.get("id"))
NODES[nid] = {
"id": nid,
"labels": n.get("labels", []),
"props": n.get("props", {}),
}
ADJ.setdefault(nid, set())
if neo_ok:
try:
labels = ":" + ":".join(NODES[nid]["labels"]) if NODES[nid]["labels"] else ""
props = NODES[nid]["props"]
cypher = f"MERGE (n{labels} {{id:$id}}) SET n += $props"
with driver.session() as s:
s.run(cypher, id=nid, props=props)
except Exception:
pass
return JSONResponse(status_code=200, content={"upserted": len(nodes)})
@app.post("/upsert_edges")
async def upsert_edges(req: Request) -> JSONResponse:
with LATENCY.labels(route="upsert_edges").time():
REQUESTS.labels(route="upsert_edges").inc()
body = await req.json()
edges = body.get("edges", [])
for e in edges:
src = str(e.get("src"))
dst = str(e.get("dst"))
etype = e.get("type", "REL")
EDGES.append({"src": src, "dst": dst, "type": etype, "props": e.get("props", {})})
ADJ.setdefault(src, set()).add(dst)
ADJ.setdefault(dst, set())
try:
if neo_ok:
cypher = "MERGE (a {id:$src}) MERGE (b {id:$dst}) MERGE (a)-[r:%s]->(b) SET r += $props" % etype
with driver.session() as s:
s.run(cypher, src=src, dst=dst, props=e.get("props", {}))
except Exception:
pass
return JSONResponse(status_code=200, content={"upserted": len(edges)})
@app.post("/neighbors")
async def neighbors(req: Request) -> JSONResponse:
with LATENCY.labels(route="neighbors").time():
REQUESTS.labels(route="neighbors").inc()
body = await req.json()
start = str(body.get("id"))
depth = int(body.get("depth", 1))
visited = set([start])
frontier = [start]
hops = 0
order = []
while frontier and hops < depth:
next_frontier = []
for nid in frontier:
for nb in ADJ.get(nid, set()):
if nb not in visited:
visited.add(nb)
next_frontier.append(nb)
order.append(NODES.get(nb, {"id": nb}))
frontier = next_frontier
hops += 1
return JSONResponse(status_code=200, content={"neighbors": order})
# Prometheus metrics
metrics_app = make_asgi_app()
app.mount("/metrics", metrics_app)
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=PORT)
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