improvements to lambda wrapper [#13]

lambda/tippecanoe.py

@@ -0,0 +1,48 @@
+import os
+import json
+import subprocess
+import sys
+import boto3
+# if the input bucket is publicly readable
+# from botocore import UNSIGNED
+# from botocore.config import Config
+#s3 = boto3.client('s3',config=Config(signature_version=UNSIGNED))
+
+def lambda_handler(event, context):
+    bucket_name = event['Records'][0]['s3']['bucket']['name']
+    input_key = event['Records'][0]['s3']['object']['key']
+    tmpdir = '/tmp'
+    run_tippecanoe('tippecanoe',tmpdir,bucket_name, input_key)
+    return {
+        'statusCode': 200,
+        'body': json.dumps('Done!')
+    }
+
+# input formats: "geojsonseq", "fgb", "geobuf", "geojson", "csv"
+def split_key(key):
+    if key.endswith(".gz"):
+        root, ext = os.path.splitext(key[0:-3])
+        return root, ext + ".gz"
+    else:
+        return os.path.splitext(key)
+
+def run_tippecanoe(executable, tmpdir, bucket_name, input_key):
+    s3 = boto3.client('s3')
+    root, ext = split_key(input_key)
+    input_path = os.path.join(tmpdir,'input' + ext)
+    output_path = os.path.join(tmpdir,'output.mbtiles')
+    s3.download_file(bucket_name,input_key,input_path)
+    p = subprocess.Popen([executable,'-o',output_path,input_path,'--force','-u','-U','5'],stderr=subprocess.PIPE)
+    for line in p.stderr:
+        try:
+            j = json.loads(line)
+            s3.put_object(Body=json.dumps(j),Bucket=os.environ['OUTPUT_BUCKET'],Key=root + ".progress")
+        except json.decoder.JSONDecodeError:
+            pass
+    s3.upload_file(output_path,os.environ['OUTPUT_BUCKET'],root + ".mbtiles")
+
+if __name__ == "__main__":
+    tmpdir = 'tmp'
+    bucket_name = sys.argv[1]
+    input_key = sys.argv[2]
+    run_tippecanoe('../tippecanoe', tmpdir, bucket_name, input_key)