aws lambda has configurable tile_path and pmtiles_path

serverless/aws/lambda_function.py

@@ -5,7 +5,11 @@ import gzip
 import json
 import os
 import re
+
+# Exists inside all lambda functions
 import boto3
+
+# create_lambda_function.py will vendor the relevant file
 import pmtiles
 
 Zxy = collections.namedtuple("Zxy", ["z", "x", "y"])
@@ -13,7 +17,9 @@ Zxy = collections.namedtuple("Zxy", ["z", "x", "y"])
 s3 = boto3.client("s3")
 
 
-@lru_cache
+# Given a 512MB lambda function, use half of the memory for the cache,
+# assuming the average root/leaf/tile size is 512 KB
+@lru_cache(maxsize=500)
 def get_object_bytes(key, offset, length):
     end = offset + length - 1
     return (
@@ -27,29 +33,53 @@ def get_object_bytes(key, offset, length):
     )
 
 
-def parse_tile_uri(str):
-    m = re.match("^(?:/([0-9a-zA-Z/!\-_\.\*'\(\)]+))?/(\d+)/(\d+)/(\d+).pbf$", str)
+def pmtiles_path(p, tileset):
+    if not p:
+        p = "{tileset}.pmtiles"
+    return p.replace("{tileset}", tileset)
+
+
+def parse_tile_path(p, str):
+    if not p:
+        p = "/{tileset}/{z}/{x}/{y}.pbf"
+    p = re.escape(p)
+    p = p.replace(r"\{tileset\}", r"(?P<tileset>[0-9a-zA-Z/!\-_\.\*'\(\)]+)")
+    p = p.replace(r"\{z\}", r"(?P<z>\d+)")
+    p = p.replace(r"\{x\}", r"(?P<x>\d+)")
+    p = p.replace(r"\{y\}", r"(?P<y>\d+)")
+    m = re.match(f"^{p}$", str)
     if not m:
         return None, None
-    return (m.group(1), Zxy(int(m.group(2)), int(m.group(3)), int(m.group(4))))
+    return (
+        m.group("tileset"),
+        Zxy(int(m.group("z")), int(m.group("x")), int(m.group("y"))),
+    )
 
 
+# Assumes event is a API Gateway V2 or Lambda Function URL formatted dict
+# and returns API Gateway V2 / Lambda Function dict responses
+# Does not work with CloudFront events/Lambda@Edge; see README
 def lambda_handler(event, context):
     start = datetime.now()
-    uri = event["rawPath"]  # API Gateway and Lambda Function URLs
-    tileset, tile = parse_tile_uri(uri)
+    uri = event["rawPath"]
+    tileset, tile = parse_tile_uri(os.environ.get("TILE_PATH"), uri)
 
     if not tile:
         return {"statusCode": 400, "body": "Invalid Tile URL"}
 
     def get_bytes(offset, length):
-        return get_object_bytes(tileset + ".pmtiles", offset, length)
+        return get_object_bytes(
+            pmtiles_path(os.environ.get("PMTILES_PATH"), tileset), offset, length
+        )
 
     reader = pmtiles.Reader(get_bytes)
     tile_data = reader.get(tile.z, tile.x, tile.y)
     if not tile_data:
         return {"statusCode": 404, "body": "Tile not found"}
 
+    # CloudFront requires decompressed responses from lambda
+    # in order to implement the Compressed CacheOptimized policy correctly
+    # as well as Brotli support
     if reader.header().metadata.get("compression") == "gzip":
         tile_data = gzip.decompress(tile_data)
 

serverless/aws/test_lambda_function.py

@@ -1,18 +1,46 @@
 import unittest
-from lambda_function import parse_tile_uri
+from lambda_function import parse_tile_path, pmtiles_path
 
 
 class TestLambda(unittest.TestCase):
-    def test_parse_regex(self):
-        tileset, tile = parse_tile_uri("/0/0/0.pbf")
-        self.assertEqual(tileset, None)
-        self.assertEqual(tile.x, 0)
-        self.assertEqual(tile.y, 0)
-        self.assertEqual(tile.z, 0)
-
-        tileset, tile = parse_tile_uri("abcd")
+    def test_parse_tile_default(self):
+        tileset, tile = parse_tile_path(None, "abcd")
         self.assertEqual(tile, None)
 
+        tileset, tile = parse_tile_path(None, "/foo/11/22/33.pbf")
+        self.assertEqual(tileset, "foo")
+        self.assertEqual(tile.z, 11)
+        self.assertEqual(tile.x, 22)
+        self.assertEqual(tile.y, 33)
+
+    def test_parse_tile_path_setting(self):
+        tileset, tile = parse_tile_path(
+            "/{tileset}/{z}/{y}/{x}.pbf", "/foo/11/22/33.pbf"
+        )
+        self.assertEqual(tile.x, 33)
+        self.assertEqual(tile.y, 22)
+
+        tileset, tile = parse_tile_path(
+            "/tiles/{tileset}/{z}/{x}/{y}.mvt", "/tiles/foo/4/2/3.mvt"
+        )
+        self.assertEqual(tileset, "foo")
+        self.assertEqual(tile.z, 4)
+        self.assertEqual(tile.x, 2)
+        self.assertEqual(tile.y, 3)
+
+    def test_parse_tile_path_setting_special_chars(self):
+        tileset, tile = parse_tile_path(
+            "/folder(new/{tileset}/{z}/{y}/{x}.pbf", "/folder(new/foo/11/22/33.pbf"
+        )
+        self.assertEqual(tileset, "foo")
+
+    def test_pmtiles_path(self):
+        self.assertEqual(pmtiles_path(None, "foo"), "foo.pmtiles")
+        self.assertEqual(
+            pmtiles_path("folder/{tileset}/file.pmtiles", "foo"),
+            "folder/foo/file.pmtiles",
+        )
+
 
 if __name__ == "__main__":
     unittest.main()