Merge ~peppepetra/grafana-snap:lp1999071 into grafana-snap:master

[Giuseppe Petralia]

Install nodejs/npm from official repo

Closes-Bug: #1999071

[Giuseppe Petralia (peppepetra)]

It builds on all archs:

  amd64: https://launchpad.net/~llama-charmers/+snap/grafana/+build/1962543
  arm64: https://launchpad.net/~llama-charmers/+snap/grafana/+build/1962550
  s390x: https://launchpad.net/~llama-charmers/+snap/grafana/+build/1962548
  pcc64el: https://launchpad.net/~llama-charmers/+snap/grafana/+build/1962549

[Gabriel Cocenza (gabrielcocenza)]

LGTM

review: Approve

[Erhan Sunar (esunar)]

review: Approve

[Martin Kalcok (martin-kalcok)]

I have just one observation, I don't think it's blocker.
I was recently working on a snap that was building a js app with yarn and it was enough to include "node" in "stage-snaps" so maybe there's no need to have this complicated manual installation in "override-build".

Also, if this snap is meant to be installed in environment with proxy (for example launchpad's snap farm) the yarn needs to have proxy settings explicitly configured (just something to consider.)

This snippet is an example that worked for me:
```
  web-interface:
    plugin: dump
    source: ./<path_to_js_app>/
    override-build: |
      npm install --global yarn
      set +u
      if [[ -n $http_proxy ]]; then yarn config set httpProxy $http_proxy; fi
      if [[ -n $https_proxy ]]; then yarn config set httpsProxy $https_proxy; fi
      set -u
      yarn install
      yarn build
      cp -r dist $SNAPCRAFT_PART_INSTALL/
    organize:
      dist: web-ui
    stage-snaps:
      - node
```

[Eric Chen (eric-chen)]

After confirm with Giuseppe, he wants to revisit this with Martin suggestions
Change the status to WIP

[Giuseppe Petralia (peppepetra)]

I looked at Martin suggestion, unfortunately grafana 7.5.17 requires node 14 to build [1] and the snap 14/stable is not available for all the archs supported by the charm so I can't use stage-snaps.

1. https://github.com/grafana/grafana/blob/v7.5.17/contribute/developer-guide.md

2. https://snapcraft.io/node

diff --git a/snapcraft.yaml b/snapcraft.yaml
index 97d5228..edcbf60 100644
--- a/snapcraft.yaml
+++ b/snapcraft.yaml
@@ -55,19 +55,34 @@ parts:
     source: https://github.com/grafana/grafana.git
     source-tag: v${SNAPCRAFT_PROJECT_VERSION}
     build-packages: [curl,python2-minimal,python2-dev]
+    build-environment:
+      - NODE_VERSION: "14.15.5"
     override-build: |
       set -x
-      curl -sL https://deb.nodesource.com/setup_14.x | sudo -E bash -
-      apt install -y nodejs
+      # install the official nodejs
+      if [ $SNAP_ARCH == "amd64" ]; then
+        ARCH=x64
+      elif [ $SNAP_ARCH == "armhf" ]; then
+        ARCH=armv7l
+      elif [ $SNAP_ARCH == "ppc64el" ]; then
+        ARCH=ppc64le
+      else
+        ARCH=$SNAP_ARCH
+      fi
+
+      NODE_URI="https://nodejs.org/dist/v${NODE_VERSION}/node-v${NODE_VERSION}-linux-${ARCH}.tar.gz"
+      echo Fetching: $NODE_URI
+      if [ ! -f "${SNAPCRAFT_PART_BUILD}/bin/node" ]; then
+          curl $NODE_URI | tar xzf - -C $SNAPCRAFT_PART_BUILD/ --no-same-owner --strip-components=1
+      fi
+      
+      # Add nodejs/npm to the path
+      export PATH=${SNAPCRAFT_PART_BUILD}/bin:${PATH}
+      
+      npm config set unsafe-perm true
+      
       npm install --global yarn patch-package
-      # on arm, s390x, and ppc systems remove phantomjs as required from the
-      # package.json and yarn lock as it's not available from npm on those
-      # architectures
-      ARCH=$(uname -m)
-      case $ARCH in
-      arm*|s390*|ppc*)
-        yarn remove phantomjs-prebuilt --ignore-workspace-root-check;;
-      esac
+      
       export PYTHON=/usr/bin/python2
       PATH="$PATH:$SNAPCRAFT_PART_BUILD/node_modules/.bin:$SNAPCRAFT_PART_INSTALL/bin"
       NODE_ENV="production"