Adds libyaml based extension for PyYAML wheel

[kushaldas]

I did a rebuild of the PyYAML-5.4.1 wheel, which now contains the cython extension. This is what we are seeing in the CI as libyaml-dev is present in the system.j

The commit also adds libyaml-0-2 to the dependency for securedrop-proxy package.

Related to #241

How to test?

• ./scripts/install-deps
• ./scripts/build-sync-wheels --clobber -p ../securedrop-proxy

This should generate the same wheel (with the same sha256sum).

After this one can build a debian package for securedrop-proxy and try to install it in a Debian Buster vm/container to verify that it installs.

[kushaldas]

Ouch, missed steps, adding another commit.

[conorsch]

CI is passing here, with temporary commit. Sharing temporary commit below, in case it's useful for later reference. I'm going to proceed with merging freedomofpress/securedrop-proxy#87, then dropping the temp commit and performing final review here.

contents of the temp commit for later reference

diff --git a/.circleci/config.yml b/.circleci/config.yml
index e6aa2d7..ab181bb 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -83,6 +83,7 @@ common-steps:
       command: |
         mkdir ~/packaging && cd ~/packaging
         git clone https://github.com/freedomofpress/securedrop-proxy.git
+        git -C securedrop-proxy checkout update_pyyaml_wheel
         export PKG_NAME="securedrop-proxy"
         # Enable access to this env var in subsequent run steps
         echo $PKG_NAME > ~/packaging/sd_package_name
diff --git a/scripts/build-sync-wheels b/scripts/build-sync-wheels
index 755cc9e..cdf40d5 100755
--- a/scripts/build-sync-wheels
+++ b/scripts/build-sync-wheels
@@ -49,6 +49,8 @@ def main():
         git_clone_directory = tempfile.mkdtemp(prefix=os.path.basename(args.p))
         cmd = f"git clone {args.p} {git_clone_directory}".split()
         subprocess.check_call(cmd)
+        if "securedrop-proxy" in args.p:
+            subprocess.check_call(f"git -C {git_clone_directory} checkout update_pyyaml_wheel".split())
         args.p = git_clone_directory
     else:
         git_clone_directory = ""
diff --git a/tests/test_reproducible_debian_packages.py b/tests/test_reproducible_debian_packages.py
index 7b4360e..60e83a0 100644
--- a/tests/test_reproducible_debian_packages.py
+++ b/tests/test_reproducible_debian_packages.py
@@ -6,7 +6,7 @@ import os
 PACKAGE_BUILD_TARGETS = {
     "securedrop-client": "main",
     "securedrop-log": "main",
-    "securedrop-proxy": "main",
+    "securedrop-proxy": "update_pyyaml_wheel",
     "securedrop-export": "main",
 }

[conorsch]

I'm seeing the same wheel hash locally as what's being built in CI. Approving, now that freedomofpress/securedrop-proxy#87 is merged. Optimistic this will unblock work in #243