added support for snap builds closes #19;

added snap build action workflow

.dockerignore

@@ -242,3 +242,5 @@ fabric.properties
 # Custom rules
 .github
 docker
+snap
+*.snap

.github/workflows/snap-publish-release.yml

@@ -0,0 +1,23 @@
+name: snap release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout code
+        uses: actions/checkout@v2
+
+      - name: build snap
+        uses: snapcore/action-build@v1
+
+      - name: publish snap
+        uses: snapcore/action-publish@v1
+        with:
+          store_login: ${{ secrets.SNAP_LOGIN }}
+          snap: ${{ steps.build.outputs.snap }}
+          release: stable

.github/workflows/snap-publish-unstable.yml

@@ -0,0 +1,24 @@
+name: snap unstable
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout code
+        uses: actions/checkout@v2
+
+      - name: build snap
+        uses: snapcore/action-build@v1
+
+      - name: publish snap
+        uses: snapcore/action-publish@v1
+        with:
+          store_login: ${{ secrets.SNAP_LOGIN }}
+          snap: ${{ steps.build.outputs.snap }}
+          release: edge

.gitignore

@@ -265,3 +265,4 @@ dmypy.json
 # Custom rules
 test_certbot
 *.ini
+*.snap

snap-requirements.txt

@@ -0,0 +1,2 @@
+requests>=2.20.0
+zope.interface>=5.0.0

snap/hooks/post-refresh

@@ -0,0 +1,21 @@
+#!/bin/sh -e
+# This file is generated automatically and should not be edited manually.
+
+# get certbot version
+if [ ! -f "$SNAP/certbot-shared/certbot-version.txt" ]; then
+  echo "No certbot version available; not doing version comparison check" >> "$SNAP_DATA/debuglog"
+  exit 0
+fi
+cb_installed=$(cat $SNAP/certbot-shared/certbot-version.txt)
+
+# get required certbot version for plugin. certbot version must be at least the plugin's
+# version. note that this is not the required version in setup.py, but the version number itself.
+cb_required=$(grep -oP "version = '\K.*(?=')" $SNAP/setup.py)
+
+
+$SNAP/bin/python3 -c "import sys; from packaging import version; sys.exit(1) if  version.parse('$cb_installed') < version.parse('$cb_required') else sys.exit(0)" || exit_code=$?
+if [ "$exit_code" -eq 1 ]; then
+  echo "Certbot is version $cb_installed but needs to be at least $cb_required before" \
+    "this plugin can be updated; will try again on next refresh."
+  exit 1
+fi

snap/snapcraft.yaml

@@ -0,0 +1,48 @@
+name: certbot-dns-duckdns
+summary: DuckDNS Authenticator plugin for Certbot
+description: DuckDNS Authenticator plugin for Certbot
+confinement: strict
+grade: stable
+base: core20
+adopt-info: certbot-dns-duckdns
+
+parts:
+  certbot-dns-duckdns:
+    plugin: python
+    source: .
+    override-pull: |
+      snapcraftctl pull
+      snapcraftctl set-version `grep ^__version__ $SNAPCRAFT_PART_SRC/certbot_dns_duckdns/__init__.py | cut -f2 -d= | tr -d "\"[:space:]\""`
+    build-environment:
+      - PIP_CONSTRAINT: $SNAPCRAFT_PART_SRC/snap-constraints.txt
+      - SNAP_BUILD: "True"
+    requirements:
+      - snap-requirements.txt
+    build-packages:
+      - gcc
+      - git
+      - build-essential
+      - libssl-dev
+      - libffi-dev
+      - python3-dev
+      - cargo
+  certbot-metadata:
+    plugin: dump
+    source: .
+    stage: [ setup.py, certbot-shared ]
+    override-pull: |
+      snapcraftctl pull
+      mkdir -p $SNAPCRAFT_PART_SRC/certbot-shared
+
+slots:
+  certbot:
+    interface: content
+    content: certbot-1
+    read:
+      - $SNAP/lib/python3.8/site-packages
+
+plugs:
+  certbot-metadata:
+    interface: content
+    content: metadata-1
+    target: $SNAP/certbot-shared