--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/snp-cache.py	Wed Jan 24 14:18:21 2018 -0500
@@ -0,0 +1,147 @@
+#! /usr/bin/env python3.6
+
+import boto3
+from botocore.exceptions import ClientError, DataNotFoundError, NoCredentialsError, BotoCoreError
+
+import argparse
+import subprocess
+import contextlib
+import logging
+import io
+import shutil
+import os, sys
+from builtins import open as _open
+from copy import copy
+from functools import partial
+from itertools import tee
+from io import BytesIO
+from threading import Thread
+
+CACHE_NAMESPACE = 'cfsan-galaxytrakr-cache'
+
+class NoCacheNoCommandException(Exception):
+	pass
+
+@contextlib.contextmanager
+def open(filename=None, mode='r'):
+	"basically a wrapper to make sys.stdout usable where there's a contextmanager"
+	writer = sys.stdout.buffer
+	try:
+		if filename:
+			writer = io.FileIO(filename, mode)
+			if 'r' in mode:
+				writer = io.BufferedReader(writer)
+			elif 'w' in mode:
+				writer = io.BufferedWriter(writer)
+		yield writer
+		writer.flush()
+	finally:
+		if filename:
+			writer.close()
+
+# class stream_over(io.IOBase):
+# 	"a file-like object that works as a tee, for API's that accept a file-like"
+# 	def __init__(self, output_streams, input_stream=None):
+# 		self.streams = output_streams
+# 		self.input = input_stream
+
+# 	def writable(self, *a, **k):
+# 		return all([s.writeable(*a, **k) for s in self.streams])
+	
+# 	def write(self, *a, **k):
+# 		[s.write(*a, **k) for s in self.streams]
+
+# 	def writelines(self, *a, **k):
+# 		[s.writelines(*a, **k) for s in self.streams]
+
+# 	def flush(self, *a, **k):
+# 		[s.flush(*a, **k) for s in self.streams]
+
+# 	def close(self, *a, **k):
+# 		if self.input:
+# 			self.input.close()
+# 		[s.close(*a, **k) for s in self.streams]
+
+# 	def read(self, *a, **k):
+# 		if self.input:
+# 			bts = self.input.read(*a, **k)
+# 			self.write(bts)
+# 			return bts
+# 		raise ValueError("Not created with a readable stream; read ops not supported.")
+
+# 	def readlines(self, *a, **k):
+# 		if self.input:
+# 			return self.input.readlines(*a, **k)
+# 		raise ValueError("Not created with a readable stream; read ops not supported.")
+
+# 	def seekable(self):
+# 		return False
+
+# @contextlib.contextmanager
+# def multiwrite(*streams):
+# 	multistream = stream_over(streams)
+# 	yield multistream
+# 	multistream.flush()
+# 	multistream.close()
+
+def stream_to(input_stream, output_stream):
+	for i, line in enumerate(input_stream.readlines()):
+		if i < 8:
+			logging.getLogger('strm').info(str(line[:70]))
+		output_stream.write(line)
+		
+
+
+def main(table, id, command=None, output=None, *a, **k):
+	id = id.strip()
+	table = table.strip()
+	name = f"{table}/{id}"
+	with open(output, 'wb') as output_f:
+		#lookup ID in table and get a FH to the resource
+		try:
+			api_key = os.environ.get('AWS_API_KEY', '')
+			s3 = boto3.resource('s3').Bucket(CACHE_NAMESPACE)
+			s3.download_fileobj(name, output_f)
+			logging.getLogger('snp-cache.cache').info(f"cache hit on {name}, retrieved.")
+		except (DataNotFoundError, NoCredentialsError, BotoCoreError) as e:
+			if type(e) is DataNotFoundError:
+				logging.getLogger('snp-cache.cache').info(f"cache miss on {name}")
+			else:
+				logging.getLogger('snp-cache.cache').error(e)
+			#if we couldn't find the data, we need to run the command to generate it
+			if not command:
+				raise NoCacheNoCommandException("No cached result for this id, and no command given to generate.")
+			logging.getLogger('snp-cache.cmd').info(command)
+			# sub = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+			# cached, err = sub.communicate()
+			# cached, err = io.BytesIO(cached), io.BytesIO(err)
+			try:
+				cached = subprocess.check_output(command, shell=True)
+				try:
+					s3.upload_fileobj(BytesIO(cached), name)
+				except (ClientError, BotoCoreError) as e:
+					logging.getLogger('snp-cache.cache').error('Error writing to cache:')
+					logging.getLogger('snp-cache.cache').error(e)
+				finally:
+					#stream_to(cached, output_f) #stream FROM cached TO output_f
+					output_f.write(cached)
+			except subprocess.CalledProcessError as e:
+				print(e.output, file=sys.stderr)
+				return e.returncode
+	return 0
+
+
+
+
+if __name__ == '__main__':
+	parser = argparse.ArgumentParser(description="lookup result for file in data table, or compute and install")
+	parser.add_argument('table', type=str)
+	parser.add_argument('id', type=str)
+	parser.add_argument('-c', dest='command')
+	parser.add_argument('-o', dest='output')
+	parser.add_argument('-l', dest='logging', default='/dev/null')
+	params = parser.parse_args()
+
+	logging.basicConfig(filename=params.logging,level=logging.INFO)
+
+	quit(main(**vars(params)))
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