Add Snapcraft metadata and install/maintenance hooks (#666)

* Add Snapcraft metadata and install/maintenance hooks

* Move set-environment script into snap/local

* snap: Remove diesel-cli part.

This *was* necessary as of 0.3.0, but now `plm migrations run` does the job.

* snap: Add an actual description

* snap: Add an 'enabled' config item.

Don't try to run until enabled is set, and automatically run the
migrations when we are enabled

snap/hooks/configure

@@ -0,0 +1,48 @@
+#!/bin/sh
+
+db_type="$(snapctl get db.type)"
+db_url="$(snapctl get db.url)"
+if [ "${db_type}" = "sqlite" ]
+then
+    if [ -n "${db_url}" ]
+    then
+        echo "sqlite backend does not use db.url key"
+        exit 1
+    fi
+elif [ "${db_type}" = "postgres" ]
+then
+    if [ -z "${db_url}" ]
+    then
+        echo "postgres backend requires db.url to be set"
+        exit 1
+    fi
+elif [ -n "${db_type}" ]
+then
+    echo "Invalid db.type: " ${db_type}
+    exit 1
+fi
+
+base_url="$(snapctl get base-url)"
+enabled="$(snapctl get enabled)"
+
+if [ -n ${enabled} -a \( "${enabled}" != "true" -a "${enabled}" != "false" \) ]
+then
+    echo "Invalid 'enabled' setting: ${enabled}. Valid values are 'true' or 'false'"
+    exit 1
+fi
+
+if [ -n ${base_url} -a \( -z "${enabled}" -o "${enabled}" = "false" \) ]
+then
+    echo "All required configuration available."
+    echo "Plume can now be enabled by setting 'snap set plume enabled=true' and restarting the service \
+with 'snap restart plume'"
+fi
+
+if [ "${enabled}" = "true" -a ! -e ${SNAP_COMMON}/initial-migrations-run ]
+then
+    cd ${SNAP}
+    exec ./set-environment bin/plm migration run --path ${SNAP_DATA}
+    touch ${SNAP_COMMON}/initial-migrations-run
+fi
+
+exit 0

snap/hooks/install

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+openssl rand -base64 32 > ${SNAP_COMMON}/rocket-secret-key

snap/hooks/post-refresh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+db_type=$(snapctl get db.type)
+
+if [ -z "${db_type}" ]
+then
+    exit 0
+fi
+
+cd ${SNAP}
+exec ./set-environment bin/plm migration run --path ${SNAP_DATA}

snap/local/set-environment

@@ -0,0 +1,29 @@
+#!/bin/sh
+
+enabled="$(snapctl get enabled)"
+if [ -z "${enabled}" -o "${enabled}" != "true" ]
+then
+    echo "Plume not yet enabled"
+    exit 1
+fi
+
+export BASE_URL="$(snapctl get base-url)"
+database_type="$(snapctl get db.type)"
+
+if [ z"${database_type}" = z"sqlite" ]
+then
+    export DATABASE_URL=${SNAP_DATA}/plume.db
+    export MIGRATION_DIR=migrations/sqlite
+else
+    # Must be postgres, so must have set db.url
+    export DATABASE_URL="$(snapctl get db.url)"
+    export MIGRATION_DIRECTORY=migrations/postgres
+fi
+
+ROCKET_ADDRESS="$(snapctl get listen.address)"
+ROCKET_PORT="$(snapctl get listen.port)"
+export ROCKET_SECRET_KEY="$(cat ${SNAP_COMMON}/rocket-secret-key)"
+export SEARCH_INDEX="${SNAP_DATA}/search_index"
+
+cd ${SNAP}
+exec $@

snap/snapcraft.yaml

@@ -0,0 +1,50 @@
+name: plume
+base: core18
+version: '0.3.0' # just for humans, typically '1.2+git' or '1.3.2'
+summary: Multi-user blogging platform, federated over ActivityPub
+description: |
+  Plume is a federated blogging platform, featuring:
+   * A blog-centric approach: you can create as much blogs as you want with your account, to keep your different publications separated.
+   * Media management: you can upload pictures to illustrate your articles, but also audio files if you host a podcast, and manage them all from Plume.
+   * Federation: Plume is part of a network of interconnected websites called the Fediverse. Each of these websites (often called instances) have their own rules and thematics, but they can all communicate with each other.
+   * Collaborative writing: invite other people to your blogs, and write articles together.
+grade: devel # must be 'stable' to release into candidate/stable channels
+confinement: strict
+
+apps:
+  plume:
+    daemon: simple
+    command: set-environment bin/plume
+    plugs:
+      - network
+      - network-bind
+  plm:
+    command: set-environment bin/plm
+
+parts:
+  plume:
+    plugin: rust
+    source: .
+    rust-revision: nightly-2019-03-23
+    build-packages:
+      - libssl-dev
+      - pkg-config
+      - libsqlite3-dev
+      - gettext
+    after:
+      - cargo-web
+    override-build: |
+      export PATH=$PATH:$SNAPCRAFT_PROJECT_DIR/../.cargo/bin
+      cargo web deploy -p plume-front --release
+      cargo install --force --no-default-features --features sqlite --path . --root ${SNAPCRAFT_PART_INSTALL}
+      cargo install --force --no-default-features --features sqlite --path plume-cli --root ${SNAPCRAFT_PART_INSTALL}
+      cp -a assets migrations static target translations ${SNAPCRAFT_PART_INSTALL}
+      cp snap/local/set-environment ${SNAPCRAFT_PART_INSTALL}
+    stage-packages:
+      - openssl
+      - libsqlite3-0
+
+  cargo-web:
+    plugin: rust
+    source: https://github.com/koute/cargo-web.git
+    source-tag: 0.6.26