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@Jomik Jomik/
Created Apr 12, 2019

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#!/usr/bin/env nix-shell
#!nix-shell -p nix-prefetch-git -p python3 nix -i python3
# format:
# $ nix run -c black
# type-check:
# $ nix run nixpkgs.python3Packages.mypy -c mypy
# linted:
# $ nix run nixpkgs.python3Packages.flake8 -c flake8 --ignore E501,E265
import functools
import json
import os
import subprocess
import sys
import traceback
import urllib.error
import urllib.request
import xml.etree.ElementTree as ET
from datetime import datetime
from multiprocessing.dummy import Pool
from pathlib import Path
from typing import Dict, List, Optional, Tuple, Union, Any
from urllib.parse import urljoin, urlparse
from tempfile import NamedTemporaryFile
ATOM_ENTRY = "{}entry"
ATOM_LINK = "{}link"
ATOM_UPDATED = "{}updated"
ROOT = Path(__file__).parent
class Repo:
def __init__(self, owner: str, name: str) -> None:
self.owner = owner = name
def url(self, path: str) -> str:
return urljoin(f"{self.owner}/{}/", path)
def __repr__(self) -> str:
return f"Repo({self.owner}, {})"
def has_submodules(self) -> bool:
except urllib.error.HTTPError as e:
if e.code == 404:
return False
return True
def latest_commit(self) -> Tuple[str, datetime]:
with urllib.request.urlopen(self.url("commits/master.atom")) as req:
xml =
root = ET.fromstring(xml)
latest_entry = root.find(ATOM_ENTRY)
assert latest_entry is not None, f"No commits found in repository {self}"
commit_link = latest_entry.find(ATOM_LINK)
assert commit_link is not None, f"No link tag found feed entry {xml}"
url = urlparse(commit_link.get("href"))
updated_tag = latest_entry.find(ATOM_UPDATED)
assert (
updated_tag is not None and updated_tag.text is not None
), f"No updated tag found feed entry {xml}"
updated = datetime.strptime(updated_tag.text, "%Y-%m-%dT%H:%M:%SZ")
return Path(url.path).name, updated
def prefetch_git(self, ref: str) -> str:
data = subprocess.check_output(
["nix-prefetch-git", "--fetch-submodules", self.url(""), ref]
return json.loads(data)["sha256"]
def prefetch_github(self, ref: str) -> str:
data = subprocess.check_output(
["nix-prefetch-url", "--unpack", self.url(f"archive/{ref}.tar.gz")]
return data.strip().decode("utf-8")
class Plugin:
def __init__(
name: str,
commit: str,
has_submodules: bool,
sha256: str,
date: Optional[datetime] = None,
) -> None: = name
self.commit = commit
self.has_submodules = has_submodules
self.sha256 = sha256 = date
def normalized_name(self) -> str:
return".", "-")
def version(self) -> str:
assert is not None
def as_json(self) -> Dict[str, str]:
copy = self.__dict__.copy()
del copy["date"]
return copy
GET_PLUGINS = f"""(with import <localpkgs> {{}};
inherit (pkgs.callPackage ./fish-utils.nix {}) buildFishPlugin;
generated = callPackage {ROOT}/generated.nix {{
inherit buildFishPlugin;
hasChecksum = value: lib.isAttrs value && lib.hasAttrByPath ["src" "outputHash"] value;
getChecksum = name: value:
if hasChecksum value then {{
submodules = value.src.fetchSubmodules or false;
sha256 = value.src.outputHash;
rev = value.src.rev;
}} else null;
checksums = lib.mapAttrs getChecksum generated;
in lib.filterAttrs (n: v: v != null) checksums)"""
class CleanEnvironment(object):
def __enter__(self) -> None:
self.old_environ = os.environ.copy()
# local_pkgs = str(ROOT.joinpath("../../.."))
# os.environ["NIX_PATH"] = f"localpkgs={local_pkgs}"
self.empty_config = NamedTemporaryFile()
os.environ["NIXPKGS_CONFIG"] =
def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> None:
def get_current_plugins() -> List[Plugin]:
with CleanEnvironment():
out = subprocess.check_output(["nix", "eval", "--json", GET_PLUGINS])
data = json.loads(out)
plugins = []
for name, attr in data.items():
p = Plugin(name, attr["rev"], attr["submodules"], attr["sha256"])
return plugins
def prefetch_plugin(user: str, repo_name: str, cache: "Cache") -> Plugin:
repo = Repo(user, repo_name)
commit, date = repo.latest_commit()
has_submodules = repo.has_submodules()
cached_plugin = cache[commit]
if cached_plugin is not None: = repo_name = date
return cached_plugin
print(f"prefetch {user}/{repo_name}")
if has_submodules:
sha256 = repo.prefetch_git(commit)
sha256 = repo.prefetch_github(commit)
return Plugin(repo_name, commit, has_submodules, sha256, date=date)
def print_download_error(plugin: str, ex: Exception):
print(f"{plugin}: {ex}", file=sys.stderr)
ex_traceback = ex.__traceback__
tb_lines = [
for line in traceback.format_exception(ex.__class__, ex, ex_traceback)
def check_results(
results: List[Tuple[str, str, Union[Exception, Plugin]]]
) -> List[Tuple[str, str, Plugin]]:
failures: List[Tuple[str, Exception]] = []
plugins = []
for (owner, name, result) in results:
if isinstance(result, Exception):
failures.append((name, result))
plugins.append((owner, name, result))
print(f"{len(results) - len(failures)} plugins were checked", end="")
if len(failures) == 0:
return plugins
print(f", {len(failures)} plugin(s) could not be downloaded:\n")
for (plugin, exception) in failures:
print_download_error(plugin, exception)
def load_plugin_spec() -> List[Tuple[str, str]]:
plugin_file = ROOT.joinpath("fish-plugin-names")
plugins = []
with open(plugin_file) as f:
for line in f:
spec = line.strip()
parts = spec.split("/")
if len(parts) != 2:
msg = f"Invalid repository {spec}, must be in the format owner/repo"
print(msg, file=sys.stderr)
plugins.append((parts[0], parts[1]))
return plugins
def get_cache_path() -> Optional[Path]:
xdg_cache = os.environ.get("XDG_CACHE_HOME", None)
if xdg_cache is None:
home = os.environ.get("HOME", None)
if home is None:
return None
xdg_cache = str(Path(home, ".cache"))
return Path(xdg_cache, "fish-plugin-cache.json")
class Cache:
def __init__(self, initial_plugins: List[Plugin]) -> None:
self.cache_file = get_cache_path()
downloads = {}
for plugin in initial_plugins:
downloads[plugin.commit] = plugin
self.downloads = downloads
def load(self) -> Dict[str, Plugin]:
if self.cache_file is None or not self.cache_file.exists():
return {}
downloads: Dict[str, Plugin] = {}
with open(self.cache_file) as f:
data = json.load(f)
for attr in data.values():
p = Plugin(
attr["name"], attr["commit"], attr["has_submodules"], attr["sha256"]
downloads[attr["commit"]] = p
return downloads
def store(self) -> None:
if self.cache_file is None:
os.makedirs(self.cache_file.parent, exist_ok=True)
with open(self.cache_file, "w+") as f:
data = {}
for name, attr in self.downloads.items():
data[name] = attr.as_json()
json.dump(data, f, indent=4, sort_keys=True)
def __getitem__(self, key: str) -> Optional[Plugin]:
return self.downloads.get(key, None)
def __setitem__(self, key: str, value: Plugin) -> None:
self.downloads[key] = value
def prefetch(
args: Tuple[str, str], cache: Cache
) -> Tuple[str, str, Union[Exception, Plugin]]:
assert len(args) == 2
owner, repo = args
plugin = prefetch_plugin(owner, repo, cache)
cache[plugin.commit] = plugin
return (owner, repo, plugin)
except Exception as e:
return (owner, repo, e)
header = (
"# This file has been generated by ./pkgs/fish-plugins/ Do not edit!"
def generate_nix(plugins: List[Tuple[str, str, Plugin]]):
sorted_plugins = sorted(plugins, key=lambda v: v[2].name.lower())
with open(ROOT.joinpath("generated.nix"), "w+") as f:
{ lib, buildFishPlugin, fetchFromGitHub, overrides ? (self: super: {}) }:
packages = ( self:
for owner, repo, plugin in sorted_plugins:
if plugin.has_submodules:
submodule_attr = "\n fetchSubmodules = true;"
submodule_attr = ""
{plugin.normalized_name} = buildFishPlugin {{
pname = "{plugin.normalized_name}";
version = "{plugin.version}";
src = fetchFromGitHub {{
owner = "{owner}";
repo = "{repo}";
rev = "{plugin.commit}";
sha256 = "{plugin.sha256}";{submodule_attr}
in lib.fix' (lib.extends overrides packages)
print("updated generated.nix")
def main() -> None:
plugin_names = load_plugin_spec()
current_plugins = get_current_plugins()
cache = Cache(current_plugins)
prefetch_with_cache = functools.partial(prefetch, cache=cache)
# synchronous variant for debugging
# results = map(prefetch_with_cache, plugins)
pool = Pool(processes=30)
results =, plugin_names)
plugins = check_results(results)
if __name__ == "__main__":
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