Commit 36df2f39 authored by dmp's avatar dmp
Browse files

Added utility to uniquely identify ghc repo states

This commit adds python script that can be used to
create and restore "fingerprints" of a ghc repo configuration. A
fingerprint is a list of (sub-repo, commit) pairs. It can be used in
place of git submodules to record and reinstate the entire commit
state of the git repos used by ghc.
parent e7dcbdc7
#! /usr/bin/env python
# Script to create and restore a git fingerprint of the ghc repositories.
from datetime import datetime
from optparse import OptionParser
import os
import os.path
import re
import subprocess
from subprocess import PIPE, Popen
import sys
def main():
opts, args = parseopts(sys.argv[1:])
def create_action(opts):
"""Action called for the create commmand"""
if opts.fpfile:
fp =
fp = fingerprint(opts.source)
if len(fp) == 0:
error("Got empty fingerprint from source: "+str(opts.source))
if opts.output_file:
print "Writing fingerprint to: ", opts.output_file
def restore_action(opts):
"""Action called for the restore commmand"""
def branch_name(filename):
return "fingerprint_" + os.path.basename(filename).replace(".", "_")
if opts.fpfile:
fp =
bn = branch_name(opts.fpfile)
except MalformedFingerPrintError:
error("Error parsing fingerprint file: "+opts.fpfile)
if len(fp) == 0:
error("No fingerprint found in fingerprint file: "+opts.fpfile)
elif opts.logfile:
fp = fingerprint(opts.source)
bn = branch_name(opts.logfile)
if len(fp) == 0:
error("No fingerprint found in build log file: "+opts.logfile)
error("Must restore from fingerprint or log file")
restore(fp, branch_name=bn if opts.branch else None)
def fingerprint(source=None):
"""Create a new fingerprint of current repositories.
The source argument is parsed to look for the expected output
from a `sync-all` command. If the source is `None` then the
`sync-all` command will be run to get the current fingerprint.
if source is None:
sync_all = ["./sync-all", "log", "HEAD^..", "--pretty=oneline"]
source = Popen(sync_all, stdout=PIPE).stdout
lib = ""
commits = {}
for line in source.readlines():
if line.startswith("=="):
lib = line.split()[1].rstrip(":")
lib = "." if lib == "running" else lib # hack for top ghc repo
elif re.match("[abcdef0-9]{40}", line):
commit = line[:40]
commits[lib] = commit
return FingerPrint(commits)
def restore(fp, branch_name=None):
"""Restore the ghc repos to the commits in the fingerprint
This function performs a checkout of each commit specifed in
the fingerprint. If `branch_name` is not None then a new branch
will be created for the top ghc repository. We also add an entry
to the git config that sets the remote for the new branch as `origin`
so that the `sync-all` command can be used from the branch.
checkout = ["git", "checkout"]
# run checkout in all subdirs
for (subdir, commit) in fp:
if subdir != ".":
cmd = checkout + [commit]
print "==", subdir, " ".join(cmd)
if os.path.exists(subdir):
rc =, cwd=subdir)
if rc != 0:
error("Too many errors, aborting")
sys.stderr.write("WARNING: "+
subdir+" is in fingerprint but missing in working directory\n")
# special handling for top ghc repo
# if we are creating a new branch then also add an entry to the
# git config so the sync-all command is happy
branch_args = ["-b", branch_name] if branch_name else []
rc = + branch_args + [fp["."]])
if (rc == 0) and branch_name:
branch_config = "branch."+branch_name+".remote"["git", "config", "--add", branch_config, "origin"])
actions = {"create" : create_action, "restore" : restore_action}
def parseopts(argv):
"""Parse and check the validity of the command line arguments"""
usage = "fingerprint ("+"|".join(sorted(actions.keys()))+") [options]"
parser = OptionParser(usage=usage)
parser.add_option("-d", "--dir", dest="dir",
help="write output to directory DIR", metavar="DIR")
parser.add_option("-o", "--output", dest="output",
help="write output to file FILE", metavar="FILE")
parser.add_option("-l", "--from-log", dest="logfile",
help="reconstruct fingerprint from build log", metavar="FILE")
parser.add_option("-f", "--from-fp", dest="fpfile",
help="reconstruct fingerprint from fingerprint file", metavar="FILE")
parser.add_option("-n", "--no-branch",
action="store_false", dest="branch", default=True,
help="do not create a new branch when restoring fingerprint")
parser.add_option("-g", "--ghc-dir", dest="ghcdir",
help="perform actions in GHC dir", metavar="DIR")
opts,args = parser.parse_args(argv)
return (validate(opts, args, parser), args)
def validate(opts, args, parser):
""" Validate and prepare the command line options.
It performs the following actions:
* Check that we have a valid action to perform
* Check that we have a valid output destination
* Opens the output file if needed
* Opens the input file if needed
# Determine the action
opts.action = actions[args[0]]
except (IndexError, KeyError):
error("Must specify a valid action", parser)
# Inputs
if opts.logfile and opts.fpfile:
error("Must specify only one of -l and -f")
opts.source = None
if opts.logfile:
opts.source = file(opts.logfile, "r")
elif opts.fpfile:
opts.source = file(opts.fpfile, "r")
# Outputs
if opts.dir:
fname = opts.output
if fname is None:
fname ="%Y-%m%-%d_%H-%M-%S") + ".fp"
path = os.path.join(opts.dir, fname)
opts.output_file = path
opts.output = file(path, "w")
elif opts.output:
opts.output_file = opts.output
opts.output = file(opts.output_file, "w")
opts.output_file = None
opts.output = sys.stdout
# GHC Directory
# As a last step change the directory to the GHC directory specified
if opts.ghcdir:
return opts
def error(msg="fatal error", parser=None, exit=1):
"""Function that prints error message and exits"""
print "ERROR:", msg
if parser:
class MalformedFingerPrintError(Exception):
"""Exception raised when parsing a bad fingerprint file"""
class FingerPrint:
"""Class representing a fingerprint of all ghc git repos.
A finger print is represented by a dictionary that maps a
directory to a commit. The directory "." is used for the top
level ghc repository.
def __init__(self, subcommits = {}):
self.commits = subcommits
def __eq__(self, other):
if other.__class__ != self.__class__:
raise TypeError
return self.commits == other.commits
def __neq__(self, other):
not(self == other)
def __hash__(self):
return hash(str(self))
def __len__(self):
return len(self.commits)
def __repr__(self):
return "FingerPrint(" + repr(self.commits) + ")"
def __str__(self):
s = ""
for lib in sorted(self.commits.keys()):
commit = self.commits[lib]
s += "{0}|{1}\n".format(lib, commit)
return s
def __getitem__(self, item):
return self.commits[item]
def __iter__(self):
return self.commits.iteritems()
def write(self, outh):
def read(inh):
"""Read a fingerprint from a fingerprint file"""
commits = {}
for line in inh.readlines():
splits = line.strip().split("|", 1)
if len(splits) != 2:
raise MalformedFingerPrintError(line)
lib, commit = splits
commits[lib] = commit
return FingerPrint(commits)
if __name__ == "__main__":
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