Initial version of an esplora backend plugin

sauron/sauron.py

@@ -0,0 +1,135 @@
+#!/usr/bin/env python3
+import json
+import requests
+
+from art import sauron_eye
+from pyln.client import Plugin
+
+
+plugin = Plugin()
+
+
+@plugin.init()
+def init(plugin, options, configuration, **kwargs):
+    plugin.api_endpoint = options.get("sauron-api-endpoint")
+    if not plugin.api_endpoint:
+        raise Exception("You need to specify the sauron-api-endpoint option.")
+
+    plugin.log("Sauron plugin initialized")
+    plugin.log(sauron_eye)
+
+
+@plugin.method("getchaininfo")
+def getchaininfo(plugin, **kwargs):
+    blockhash_url = "{}/block-height/0".format(plugin.api_endpoint)
+    blockcount_url = "{}/blocks/tip/height".format(plugin.api_endpoint)
+    chains = {
+        "000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f":
+        "main",
+        "000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943":
+        "test",
+        "0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206":
+        "regtest"
+    }
+
+    genesis_req = requests.get(blockhash_url)
+    blockcount_req = requests.get(blockcount_url)
+    assert genesis_req.status_code == 200 and blockcount_req.status_code == 200
+    if genesis_req.text not in chains.keys():
+        raise Exception("Unsupported network")
+
+    # We wouldn't be able to hit it if its bitcoind wasn't synced, so
+    # ibd = false and headercount = blockcount
+    return {
+        "chain": chains[genesis_req.text],
+        "blockcount": blockcount_req.text,
+        "headercount": blockcount_req.text,
+        "ibd": False,
+    }
+
+
+@plugin.method("getrawblockbyheight")
+def getrawblock(plugin, height, **kwargs):
+    blockhash_url = "{}/block-height/{}".format(plugin.api_endpoint, height)
+
+    blockhash_req = requests.get(blockhash_url)
+    # FIXME: Esplora doesn't serve raw blocks !
+    # https://github.com/Blockstream/esplora/issues/171
+    block_url = "https://blockchain.info/block/{}?format=hex"
+    block_req = requests.get(block_url.format(blockhash_req.text))
+    if blockhash_req.status_code != 200 or block_req.status_code != 200:
+        return {
+            "blockhash": None,
+            "block": None,
+        }
+
+    return {
+        "blockhash": blockhash_req.text,
+        "block": block_req.text,
+    }
+
+
+@plugin.method("sendrawtransaction")
+def sendrawtx(plugin, tx, **kwargs):
+    sendtx_url = "{}/tx".format(plugin.api_endpoint)
+
+    sendtx_req = requests.post(sendtx_url, data=tx)
+    if sendtx_req.status_code != 200:
+        return {
+            "success": False,
+            "errmsg": sendtx_req.text,
+        }
+
+    return {
+        "success": True,
+        "errmsg": "",
+    }
+
+
+@plugin.method("gettxout")
+def gettxout(plugin, txid, vout, **kwargs):
+    gettx_url = "{}/tx/{}".format(plugin.api_endpoint, txid)
+    status_url = "{}/tx/{}/outspend/{}".format(plugin.api_endpoint, txid, vout)
+
+    gettx_req = requests.get(gettx_url)
+    status_req = requests.get(status_url)
+    assert gettx_req.status_code == status_req.status_code == 200
+    if json.loads(status_req.text)["spent"]:
+        return {
+            "amount": None,
+            "script": None,
+        }
+
+    txo = json.loads(gettx_req.text)["vout"][vout]
+    return {
+        "amount": txo["value"],
+        "script": txo["scriptpubkey"],
+    }
+
+
+@plugin.method("getfeerate")
+def getfeerate(plugin, blocks, mode, **kwargs):
+    feerate_url = "{}/fee-estimates".format(plugin.api_endpoint)
+    # Use an estimation provided by esplora
+    if blocks == 100:
+        blocks = 144
+
+    feerate_req = requests.get(feerate_url)
+    assert feerate_req.status_code == 200
+    feerates = json.loads(feerate_req.text)
+    # It renders sat/vB, so * 10**8 / 10**3 for BTC/kB
+    feerate = feerates[str(blocks)] * 10**5
+
+    # FIXME mode ?
+    return {
+        "feerate": int(feerate),
+    }
+
+
+plugin.add_option(
+    "sauron-api-endpoint",
+    "",
+    "The URL of the esplora instance to hit (including '/api')."
+)
+
+plugin.run()