This is tooltool. Tooltool is a program that helps make downloading large binaries easier in a CI environment. The program creates a json based manifest that is small compared to the binaries. That manifest is transmitted to the machine that needs the binary somehow (checked in, included in tarball, etc) where the machine will run tooltool to download. When using the fetch mode, the program will check to see if the file exists locally. If this file does not exist locally the program will try to fetch from one of the base URLs provided. The API that tooltool uses to fetch files is exceedingly simple. the API is that each file request will look for an http resource that is a combination of an arbitrary base url, a directory that is named as the hashing algorithm used and the hashing results of each file stored. Example, using base url of "http://localhost:8080/tooltool", algorithm of "sha512" and a file that hashes to "abcedf0123456789", tooltool would look for the file at "http://localhost:8080/tooltool/sha512/abcdef0123456789". If there is a local file that has the filename specified in the manifest already, tooltool will not overwrite by default. In this case, tooltool will exit with a non-0 exit value. If overwrite mode is enabled, tooltool will overwrite the local file with the file specified in the manifest. Developing tooltool should be easy. It is written as a single Python file. There is no 'build system' and there is not yet setuptools integration. There are, however, tests that should be run prior to merging or opening a pull request. These tests require setting up a local http server. On my machine, all of the tests can be run with "make check"