Rewrite in python

.gitignore

@@ -95,3 +95,6 @@ local.settings.json
 res/update-streetwarp.sh
 src/secret.ts
 test/testoutput.json
+.vscode
+.requirements.zip
+.serverless

README.md

@@ -6,7 +6,11 @@ to an Azure storage blob. It's designed to be called by
 [streetwarp-web](https://github.com/pelmers/streetwarp-web).
 
 `res/bin` contains static builds of streetwarp and ffmpeg which can execute on
-AWS Lambda's Ubuntu runtime.
+AWS Lambda's Node v12 runtime.
+
+### Dev Setup
+1. `npm install -g serverless`
+2. `serverless plugin install -n serverless-python-requirements`
 
 ### Usage
 

handler.py

@@ -0,0 +1,167 @@
+try:
+    import unzip_requirements
+except ImportError:
+    pass
+import asyncio
+from asyncio.subprocess import PIPE
+from asyncio import create_subprocess_exec
+import json, os, sys, subprocess
+from time import time
+from pprint import pprint
+from functools import wraps
+from tempfile import mkdtemp
+from azure.storage.blob import BlobServiceClient
+import websockets as ws
+
+
+r = lambda p: os.path.join(dirname, *p.split("/"))
+dirname = os.path.abspath(os.path.dirname(__file__))
+bin_path = r("res/bin")
+sw_path = r("res/bin/streetwarp")
+to_cdn = lambda url: url
+blob_service_client = BlobServiceClient.from_connection_string(
+    os.getenv("AZURE_STORAGE_CONNECTION_STRING")
+)
+
+
+# Define decorator that lets us @timer('msg') on functions
+def timer(msg):
+    def with_func(func):
+        @wraps(func)
+        def t(*args, **kwargs):
+            start = time()
+            try:
+                return func(*args, **kwargs)
+            except Exception as e:
+                print(f"{msg} failed with {str(e)}.", file=sys.stderr)
+                raise e
+            finally:
+                print(f"{msg}: {(time()-start)*1000:.3f}ms")
+
+        return t
+
+    return with_func
+
+
+@timer("prepare input")
+def prepare_input(key, contents, extension):
+    os.environ["PATH"] += os.pathsep + bin_path
+    os.environ["PATH"] += os.pathsep + sw_path
+    dest = mkdtemp()
+    inp = os.path.join(dest, f"{key}.{extension}")
+    with open(inp, "w") as f:
+        f.write(contents)
+    return inp
+
+
+# https://stackoverflow.com/a/53323746
+async def _read_stream(stream, callback):
+    while True:
+        line = await stream.readline()
+        if line:
+            callback(line)
+        else:
+            break
+
+
+async def run(command, args, out_callback, err_callback):
+    process = await create_subprocess_exec(command, *args, stdout=PIPE, stderr=PIPE)
+
+    await asyncio.wait(
+        [
+            _read_stream(process.stdout, out_callback),
+            _read_stream(process.stderr, err_callback),
+        ]
+    )
+
+    await process.wait()
+
+
+@timer("prepare output")
+def prepare_output(key):
+    out_dir = mkdtemp
+    out_name = os.path.join(out_dir, f"{key}.mp4")
+    return (out_dir, out_name)
+
+
+async def main_async(event):
+    key = event["key"]
+    args = event["args"]
+    extension = event["extension"]
+    contents = event["contents"]
+    callback_endpoint = event["callbackEndpoint"]
+    pprint(event)
+
+    socket = None
+    try:
+        socket = await ws.connect(callback_endpoint)
+        print(f"Connected to server {callback_endpoint}")
+    except Exception as e:
+        print(f"Could not connect websocket: {str(e)}")
+
+    in_file = prepare_input(key, contents, extension)
+    out_dir, out_name = prepare_output(key)
+    args += ["--output-dir", out_dir, "--output", out_name, in_file]
+
+    async def progress(msg):
+        if socket is not None:
+            await socket.send(msg)
+
+    @timer("upload video")
+    def upload_vid(client):
+        with open(out_name, "rb") as mp4:
+            client.upload_blob(mp4)
+
+    @timer("run streetwarp")
+    async def streetwarp():
+        stderr = []
+        result = None
+
+        def on_out(line):
+            try:
+                msg = json.loads(line)
+                if msg["type"] in ("PROGRESS", "PROGRESS_STAGE"):
+                    asyncio.get_event_loop().create_task(progress(line))
+                else:
+                    result = msg
+            except Exception as e:
+                print(f"Could not parse streetwarp output {line}", file=sys.stderr)
+
+        exit_code = await run(
+            "streetwarp", args, on_out, lambda err: stderr.append(err)
+        )
+        if exit_code != 0:
+            stderr = "\n".join(stderr)
+            print(f'streetwarp failed (args=[{" ".join(args)}])', file=sys.stderr)
+            print(f"stderr: {stderr}", file=sys.stderr)
+            raise RuntimeError(f"streetwarp failed with exit code {exit_code}")
+        return result
+
+    try:
+        metadata = streetwarp(args)
+        result = {"metadataResult": metadata}
+        if "--dry-run" not in args:
+            client = blob_service_client.get_container_client("output").get_blob_client(
+                f"{key}.mp4"
+            )
+            upload_vid(client)
+            print(f"Upload location: {client.url}")
+            result["videoResult"] = {"url": to_cdn(client.url)}
+        pprint(result)
+        return {"statusCode": 200, "body": json.dumps(result)}
+    except Exception as e:
+        return {"statusCode": 500, body: json.dumps({"error": str(e)})}
+    finally:
+        if socket is not None:
+            socket.close()
+
+
+@timer("main function")
+def main(event):
+    return asyncio.get_event_loop().run_until_complete(main_async(event))
+
+
+# expected result from test event:
+# {
+#  "statusCode": 200,
+#  "body": "{\"metadataResult\":{\"distance\":21561.385533487017,\"frames\":6,\"gpsPoints\":[{\"lat\":47.58910167467456,\"lng\":-122.2529698647992},{\"lat\":47.55999707850386,\"lng\":-122.2265548264297},{\"lat\":47.52927704962136,\"lng\":-122.2326196099177},{\"lat\":47.55173931336428,\"lng\":-122.2131310793535},{\"lat\":47.5779808,\"lng\":-122.2100971},{\"lat\":47.5893092,\"lng\":-122.2529977}],\"originalPoints\":[{\"lat\":47.58911,\"lng\":-122.25297},{\"lat\":47.58907,\"lng\":-122.25297},{\"lat\":47.58891,\"lng\":-122.25299},{\"lat\":47.58884,\"lng\":-122.25299},{\"lat\":47.58874,\"lng\":-