Almost there! Let me add a bit of context to the above.
Yesterday, as part of Nix Office hours, @tomberek helped me figure out why my builds are failing. Once again - huge thanks!
Turns out, that there was a problem with a dependency of migra called sqlbag. There was already an issue and a PR addressing the problem, but since it was not merged yet we had to apply a patch in the flake.
Patching sqlbag
This involves removing the pathlib from propagatedBuildInputs (so Nix won’t include it in build environment, which would lead to can't intern string error) and patching the setup.py so at runtime migra doesn’t expect pathlib to be available (at least that’s how I understand it - it’s complicated).
Using sed for patching seems dangerous to me, so I opted to use proper patch command. The input can be downloaded from the mentioned PR using this URL: https://github.com/djrobstep/sqlbag/pull/9.patch and has following contents:
From b9ba0504ffcbf08031da70b455162d0419494e16 Mon Sep 17 00:00:00 2001
From: Kai Groner <kai@gronr.com>
Date: Fri, 8 Jan 2021 13:50:29 -0500
Subject: [PATCH] make pathlib dependency conditional on python < 3
---
setup.py | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/setup.py b/setup.py
index cc1d743..6fef632 100644
--- a/setup.py
+++ b/setup.py
@@ -15,7 +15,10 @@
long_description=readme,
author="Robert Lechte",
author_email="robertlechte@gmail.com",
- install_requires=["pathlib", "six", "sqlalchemy"],
+ install_requires=[
+ "pathlib; python_version<'3'",
+ "six",
+ "sqlalchemy"],
zip_safe=False,
packages=find_packages(),
classifiers=["Development Status :: 3 - Alpha"],
I put it in nix/sqlbag-pathlib.patch file and modified the postPatch for sqlbag in flake.nix to look like this:
postPatch = ''
patch --input=${./nix/sqlbag-pathlib.patch}
'';
This is sufficient to build and run migra!
$ nix build
$ result/bin/migra
usage: migra [-h] [--unsafe] [--schema SCHEMA] [--exclude_schema EXCLUDE_SCHEMA]
[--create-extensions-only] [--with-privileges] [--force-utf8]
dburl_from dburl_target
migra: error: the following arguments are required: dburl_from, dburl_target
Awesome! I pushed it to my fork at GitLab (nix branch) and now I can have migra in nix shell, even together with httpie!
$ nix shell gitlab:tad-lispy/migra/nix nixpkgs#httpie
$ migra
usage: migra [-h] [--unsafe] [--schema SCHEMA] [--exclude_schema EXCLUDE_SCHEMA]
[--create-extensions-only] [--with-privileges] [--force-utf8]
dburl_from dburl_target
migra: error: the following arguments are required: dburl_from, dburl_target
$ http
usage: http [--json] [--form] [--multipart] [--boundary BOUNDARY] [--compress]
[--pretty {all,colors,format,none}] [--style STYLE] [--unsorted] [--sorted]
[--format-options FORMAT_OPTIONS] [--print WHAT] [--headers] [--body] [--verbose] [--all]
[--history-print WHAT] [--stream] [--output FILE] [--download] [--continue] [--quiet]
[--session SESSION_NAME_OR_PATH | --session-read-only SESSION_NAME_OR_PATH]
[--auth USER[:PASS]] [--auth-type {basic,digest}] [--ignore-netrc] [--offline]
[--proxy PROTOCOL:PROXY_URL] [--follow] [--max-redirects MAX_REDIRECTS]
[--max-headers MAX_HEADERS] [--timeout SECONDS] [--check-status] [--path-as-is] [--chunked]
[--verify VERIFY] [--ssl {ssl2.3,tls1,tls1.1,tls1.2}] [--ciphers CIPHERS] [--cert CERT]
[--cert-key CERT_KEY] [--ignore-stdin] [--help] [--version] [--traceback]
[--default-scheme DEFAULT_SCHEME] [--debug]
[METHOD] URL [REQUEST_ITEM [REQUEST_ITEM ...]]
http: error: the following arguments are required: URL
So this covers one of the goals. The other goal is to be able to add migra to another project as a build dependency.
Using migra in another project
This unfortunately doesn’t work for me yet. Here is a flake from another project:
{
description = "Flake with migra and httpie";
inputs = {
migra = {
url = "gitlab:tad-lispy/migra/nix";
};
};
outputs = { self, nixpkgs, migra }: {
packages.x86_64-linux.with-migra = nixpkgs.legacyPackages.x86_64-linux.stdenv.mkDerivation {
name = "with-migra";
src = ./.;
buildInputs = [
migra
nixpkgs.legacyPackages.x86_64-linux.httpie
];
};
defaultPackage.x86_64-linux = self.packages.x86_64-linux.with-migra;
};
}
With this I have http but not migra:
$ nix develop
$ http
usage: http [--json] [--form] [--multipart] [--boundary BOUNDARY] [--compress]
[--pretty {all,colors,format,none}] [--style STYLE] [--unsorted]
[--sorted] [--format-options FORMAT_OPTIONS] [--print WHAT] [--headers]
[--body] [--verbose] [--all] [--history-print WHAT] [--stream]
[--output FILE] [--download] [--continue] [--quiet]
[--session SESSION_NAME_OR_PATH | --session-read-only SESSION_NAME_OR_PATH]
[--auth USER[:PASS]] [--auth-type {basic,digest}] [--ignore-netrc]
[--offline] [--proxy PROTOCOL:PROXY_URL] [--follow]
[--max-redirects MAX_REDIRECTS] [--max-headers MAX_HEADERS]
[--timeout SECONDS] [--check-status] [--path-as-is] [--chunked]
[--verify VERIFY] [--ssl {ssl2.3,tls1,tls1.1,tls1.2}] [--ciphers CIPHERS]
[--cert CERT] [--cert-key CERT_KEY] [--ignore-stdin] [--help] [--version]
[--traceback] [--default-scheme DEFAULT_SCHEME] [--debug]
[METHOD] URL [REQUEST_ITEM [REQUEST_ITEM ...]]
http: error: the following arguments are required: URL
$ migra
migra: command not found
Why is it that I can run it with nix shell gitlab:tad-lispy/migra/nix but don’t have it in the development shell of the above flake?