remove multi-gateway functionality

In the past, the multi-gateway functionality often created more harm
than use. The functionality mainly existed, to provide a
zero-configuration experience for new users. Due to IPIP-280, this is
now less of a concern. Further, the new auto-config method encourages
new users to briefly interact with IPFS, maybe leading to a better
performing setup.

ipfsspec/async_ipfs.py

@@ -141,110 +141,6 @@ def __str__(self):
         return f"GW({self.url})"
 
 
-class GatewayState:
-    def __init__(self):
-        self.reachable = True
-        self.next_request_time = 0
-        self.backoff_time = 0
-        self.start_backoff = 1e-5
-        self.max_backoff = 5
-
-    def schedule_next(self):
-        self.next_request_time = time.monotonic() + self.backoff_time
-
-    def backoff(self):
-        if self.backoff_time < self.start_backoff:
-            self.backoff_time = self.start_backoff
-        else:
-            self.backoff_time *= 2
-        self.reachable = True
-        self.schedule_next()
-
-    def speedup(self, not_below=0):
-        did_speed_up = False
-        if self.backoff_time > not_below:
-            self.backoff_time *= 0.9
-            did_speed_up = True
-        self.reachable = True
-        self.schedule_next()
-        return did_speed_up
-
-    def broken(self):
-        self.backoff_time = self.max_backoff
-        self.reachable = False
-        self.schedule_next()
-
-    def trying_to_reach(self):
-        self.next_request_time = time.monotonic() + 1
-
-
-class MultiGateway(AsyncIPFSGatewayBase):
-    def __init__(self, gws, max_backoff_rounds=50):
-        self.gws = [(GatewayState(), gw) for gw in gws]
-        self.max_backoff_rounds = max_backoff_rounds
-
-    @property
-    def _gws_in_priority_order(self):
-        now = time.monotonic()
-        return sorted(self.gws, key=lambda x: max(now, x[0].next_request_time))
-
-    async def _gw_op(self, op):
-        for _ in range(self.max_backoff_rounds):
-            for state, gw in self._gws_in_priority_order:
-                not_before = state.next_request_time
-                if not state.reachable:
-                    state.trying_to_reach()
-                else:
-                    state.schedule_next()
-                now = time.monotonic()
-                if not_before > now:
-                    await asyncio.sleep(not_before - now)
-                logger.debug("tring %s", gw)
-                try:
-                    res = await op(gw)
-                    if state.speedup(time.monotonic() - now):
-                        logger.debug("%s speedup", gw)
-                    return res
-                except FileNotFoundError:  # early exit if object doesn't exist
-                    raise
-                except (RequestsTooQuick, aiohttp.ClientResponseError, asyncio.TimeoutError) as e:
-                    state.backoff()
-                    logger.debug("%s backoff %s", gw, e)
-                    break
-                except IOError as e:
-                    exception = e
-                    state.broken()
-                    logger.debug("%s broken", gw)
-                    continue
-            else:
-                raise exception
-        raise RequestsTooQuick()
-
-    async def api_get(self, endpoint, session, **kwargs):
-        return await self._gw_op(lambda gw: gw.api_get(endpoint, session, **kwargs))
-
-    async def api_post(self, endpoint, session, **kwargs):
-        return await self._gw_op(lambda gw: gw.api_post(endpoint, session, **kwargs))
-
-    async def cid_head(self, path, session, headers=None, **kwargs):
-        return await self._gw_op(lambda gw: gw.cid_head(path, session, headers=headers, **kwargs))
-
-    async def cid_get(self, path, session, headers=None, **kwargs):
-        return await self._gw_op(lambda gw: gw.cid_get(path, session, headers=headers, **kwargs))
-
-    async def cat(self, path, session):
-        return await self._gw_op(lambda gw: gw.cat(path, session))
-
-    async def ls(self, path, session):
-        return await self._gw_op(lambda gw: gw.ls(path, session))
-
-    def state_report(self):
-        return "\n".join(f"{s.next_request_time}, {gw}" for s, gw in self.gws)
-
-    def __str__(self):
-        return "Multi-GW(" + ", ".join(str(gw) for _, gw in self.gws) + ")"
-
-
 async def get_client(**kwargs):
     timeout = aiohttp.ClientTimeout(sock_connect=1, sock_read=5)
     kwargs = {"timeout": timeout, **kwargs}

test/test_async.py

@@ -1,6 +1,6 @@
 import pytest
 import pytest_asyncio
-from ipfsspec.async_ipfs import AsyncIPFSGateway, MultiGateway, AsyncIPFSFileSystem
+from ipfsspec.async_ipfs import AsyncIPFSGateway, AsyncIPFSFileSystem
 import aiohttp
 
 TEST_ROOT = "QmW3CrGFuFyF3VH1wvrap4Jend5NRTgtESDjuQ7QhHD5dd"
@@ -39,23 +39,6 @@ async def test_get_cid_of_folder(gw_host, session):
     assert info["CID"] == TEST_ROOT
 
 
-@pytest.mark.local_gw
-@pytest.mark.parametrize("gw_hosts", [
-    ["http://127.0.0.1:8080"],
-    ["http://127.0.0.1:9999", "http://127.0.0.1:8080"],
-    ["http://127.0.0.1:8080", "http://127.0.0.1:9999"],
-    ["https://ipfs.io", "http://127.0.0.1:8080"],
-    ["http://127.0.0.1:8080", "https://ipfs.io"],
-])
-@pytest.mark.asyncio
-async def test_multi_gw_cat(gw_hosts, session):
-    gws = [AsyncIPFSGateway(gw_host) for gw_host in gw_hosts]
-    gw = MultiGateway(gws)
-
-    res = await gw.cat(TEST_ROOT + "/default", session)
-    assert res == REF_CONTENT
-
-
 @pytest.mark.asyncio
 async def test_ls(event_loop):
     AsyncIPFSFileSystem.clear_instance_cache()  # avoid reusing old event loop