trivial: snap: pull from edge channel to build

Due to bug https://bugs.launchpad.net/snapcraft/+bug/1817300 snaps
using classic confinement began failing to build recently when
using docker.

This is also discussed in
https://forum.snapcraft.io/t/snap-build-started-failing-with-pip-not-working/10142/3

This commit can be reverted when snapcraft migrates to the stable
channel.

Fixes: #1041

.circleci/config.yml

@@ -2,7 +2,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: cibuilds/snapcraft:stable
+      - image: superm1/snapcraft-edge:latest
     steps:
       - checkout
       - run:

contrib/ci/Dockerfile-snap.in

@@ -1,6 +1,25 @@
-FROM snapcore/snapcraft
-RUN mkdir /build
-WORKDIR /build
-COPY . .
-RUN apt update
-CMD ["./contrib/ci/snap.sh"]
+FROM ubuntu:xenial
+
+RUN apt-get update && \
+  apt-get dist-upgrade --yes && \
+  apt-get install --yes \
+  curl sudo jq squashfs-tools && \
+  curl -L $(curl -H 'X-Ubuntu-Series: 16' 'https://api.snapcraft.io/api/v1/snaps/details/core' | jq '.download_url' -r) --output core.snap && \
+  mkdir -p /snap/core && unsquashfs -d /snap/core/current core.snap && rm core.snap && \
+  curl -L $(curl -H 'X-Ubuntu-Series: 16' 'https://api.snapcraft.io/api/v1/snaps/details/snapcraft?channel=edge' | jq '.download_url' -r) --output snapcraft.snap && \
+  mkdir -p /snap/snapcraft && unsquashfs -d /snap/snapcraft/current snapcraft.snap && rm snapcraft.snap && \
+  apt remove --yes --purge curl jq squashfs-tools && \
+  apt-get autoclean --yes && \
+  apt-get clean --yes
+
+COPY contrib/ci/snapcraft-wrapper /snap/bin/snapcraft
+ENV PATH=/snap/bin:$PATH
+
+LABEL maintainer="Mario Limonciello <mario.limonciello@dell.com>"
+RUN apt-get update && apt-get install -y \
+	curl \
+	git \
+	jq \
+	openssh-client \
+	wget
+WORKDIR /root/project

contrib/ci/snapcraft-wrapper

@@ -0,0 +1,12 @@
+#!/bin/sh
+SNAP="/snap/snapcraft/current"
+SNAP_NAME="$(awk '/^name:/{print $2}' $SNAP/meta/snap.yaml)"
+SNAP_VERSION="$(awk '/^version:/{print $2}' $SNAP/meta/snap.yaml)"
+SNAP_ARCH="amd64"
+
+export SNAP
+export SNAP_NAME
+export SNAP_VERSION
+export SNAP_ARCH
+
+exec "$SNAP/usr/bin/python3" "$SNAP/bin/snapcraft" "$@"