moar buffer

Dockerfile

@@ -6,6 +6,6 @@ RUN yarn install
 
 ENV TILE_SET_CACHE 128
 ENV TILE_SET_PATH /app/data
-ENV MAX_POST_SIZE 500kb
+ENV MAX_POST_SIZE 700kb
 
 CMD ["yarn", "run", "start"]

README.md

@@ -4,11 +4,12 @@ Elevation service that works with the [Terrain data provided on Amazon AWS S3](h
 
 Inspired by:
 
-* https://github.com/perliedman/elevation-service
-* https://github.com/perliedman/node-hgt
+- https://github.com/perliedman/elevation-service
+- https://github.com/perliedman/node-hgt
 
 ## API usage
-The service has a very simple API. Just post your latitude-longitude pairs as a JSON array to the service and receive an array of elevations as response. Maximum post payload is by default 500 KB.
+
+The service has a very simple API. Just post your latitude-longitude pairs as a JSON array to the service and receive an array of elevations as response. Maximum post payload is by default 700 KB (which fits roughly 10,000 points).
 
 ```bash
 # > [[lat, lng], ...]
@@ -19,21 +20,25 @@ curl -d '[[51.3, 13.4], [51.4, 13.3]]' -XPOST -H 'Content-Type: application/json
 ## Usage with pre-downloaded data
 
 Download data (ca. 200 GB):
+
 ```bash
 aws s3 cp --recursive s3://elevation-tiles-prod/skadi /path/to/data/folder
 ```
 
 Run the docker container:
+
 ```bash
 docker run --rm -v/path/to/data/folder:/app/data -p3000:3000 normanrz/elevation-service
 ```
 
 ## Usage with S3-hosted data
 
 Run the docker container:
+
 ```bash
 docker run --rm -eTILE_SET_PATH=s3:// -p3000:3000 normanrz/elevation-service
 ```
 
 ## License
-MIT
+
+MIT

index.js

@@ -1,9 +1,11 @@
 const { json, send } = require("micro");
+const limitedMap = require("limited-map");
 const { FileTileSet, S3TileSet } = require("./tileset");
 
 const cacheSize = process.env.TILE_SET_CACHE || 128;
 const tileFolder = process.env.TILE_SET_PATH || __dirname;
 const maxPostSize = process.env.MAX_POST_SIZE || "500kb";
+const maxParallelProcessing = 500;
 
 const tiles = tileFolder.startsWith("s3://")
   ? new S3TileSet({ cacheSize })
@@ -14,11 +16,18 @@ module.exports = async (req, res) => {
     return send(res, 405, { error: "Only POST allowed" });
   }
 
-  const geojson = await json(req, { limit: maxPostSize });
-  if (!geojson || Object.keys(geojson).length === 0) {
-    return send(res, 400, { error: "Invalid GeoJSON" });
+  const payload = await json(req, { limit: maxPostSize });
+  if (!payload || Object.keys(payload).length === 0) {
+    return send(res, 400, {
+      error:
+        "Invalid Payload. Expected a JSON array with latitude-longitude pairs: [[lat, lng], ...]"
+    });
   }
 
-  const result = await Promise.all(geojson.map(ll => tiles.getElevation(ll)));
+  const result = await limitedMap(
+    payload,
+    ll => tiles.getElevation(ll),
+    maxParallelProcessing
+  );
   return result;
 };

package.json

@@ -10,6 +10,7 @@
   "author": "Norman Rzepka <[email protected]>",
   "license": "MIT",
   "dependencies": {
+    "limited-map": "^0.0.1",
     "lru-memoize": "^1.0.2",
     "micro": "^9.3.2"
   },

yarn.lock

@@ -71,6 +71,10 @@ [email protected]:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/is-stream/-/is-stream-1.1.0.tgz#12d4a3dd4e68e0b79ceb8dbc84173ae80d91ca44"
 
+limited-map@^0.0.1:
+  version "0.0.1"
+  resolved "https://registry.yarnpkg.com/limited-map/-/limited-map-0.0.1.tgz#78a24fd73b0fb58312f7d639ca572b1bfd3f0bf0"
+
 lru-memoize@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/lru-memoize/-/lru-memoize-1.0.2.tgz#f5ae84d288e7d55fec8388ec0bd725621bc815d0"