#!/usr/bin/env bash
#
# JbTecWiz Support Centre -- generated fix script
#
# Fault : "Cannot connect to the Docker daemon"
# Fix   : Grant socket access, understanding what it means
# Source: https://jbtecwiz.com/support/lnx-ctr-daemon
#
# Run as     : Root shell
# Expect     : 10 minutes
# Risk       : high
# Reversible : yes
#
# WHEN THIS IS THE RIGHT FIX
#   Permission denied.
#
# HOW TO UNDO IT
#   sudo gpasswd -d $USER docker removes the group membership.
#
# Walks the fix one step at a time and asks before each. Steps with no
# command are yours to do -- it prints those and waits. DRYRUN=1 prints
# without executing; UNATTENDED=1 does not ask.
#
# --------------------------------------------------------------------
# NO WARRANTY - USE AT YOUR OWN RISK
#
# This script is provided by JbTecWiz as-is and with no warranty of any
# kind, express or implied. You run it entirely at your own risk.
#
# JbTecWiz accepts no liability for any loss or damage arising from its
# use, including but not limited to data loss, downtime, or configuration
# changes that turn out to be wrong for your system.
#
# You are responsible for reading this script before running it, for
# satisfying yourself that it suits the machine in front of you, and for
# having a working backup first. Some steps cannot be undone.
# --------------------------------------------------------------------

set -uo pipefail
DRYRUN="${DRYRUN:-0}"
UNATTENDED="${UNATTENDED:-0}"
failed=0

if [ "$(id -u)" -ne 0 ]; then
  echo "  This fix is documented as needing root. Re-run with sudo." >&2
  exit 3
fi

rule() { printf "\n%s\n" "$(printf '-%.0s' $(seq 1 70))"; if [ $# -gt 0 ]; then echo "$1"; fi; }
prose() { echo "$1" | fold -s -w 74 | sed "s/^/  /"; }

# Returns 0 when the caller should run the command, 1 when it should not.
# A manual step always returns 1 -- there is nothing for the caller to run.
step() {  # step <n> <do> <why> <manual|cmd> [command lines...]
  local n="$1" dotext="$2" why="$3" mode="$4"; shift 4
  rule "  Step $n of 5"
  prose "$dotext"
  if [ -n "$why" ]; then echo; prose "$why"; fi
  if [ "$mode" = "manual" ]; then
    echo; echo "  -> Do this yourself, then press Enter to carry on."
    if [ "$UNATTENDED" = "0" ] && [ "$DRYRUN" = "0" ]; then read -r _; fi
    return 1
  fi
  echo; printf "    %s\n" "$@"; echo
  if [ "$DRYRUN" = "1" ]; then echo "  (dry run -- not executed)"; return 1; fi
  if [ "$UNATTENDED" = "0" ]; then
    read -r -p "  Run this step? [Y]es / [S]kip / [Q]uit " a
    case "$a" in
      [Qq]*) echo "  Stopped at your request."; exit 0 ;;
      [Ss]*) echo "  Skipped."; return 1 ;;
    esac
  fi
  return 0
}

rule
echo "  "Cannot connect to the Docker daemon""
echo "  Grant socket access, understanding what it means"
echo
echo "  Risk: high   Reversible   10 minutes"
echo
prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.'
rule
echo
if [ "$UNATTENDED" = "0" ] && [ "$DRYRUN" = "0" ]; then
  read -r -p "  Ready? [y/N] " go
  case "$go" in [Yy]*) ;; *) echo "  Nothing was changed."; exit 0;; esac
fi

if step 1 'Confirm the socket and its ownership.' '' cmd 'ls -l /var/run/docker.sock' 'id'; then
  ls -l /var/run/docker.sock
  id
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 1 failed. The rest of the fix may depend on it." >&2
  fi
fi

step 2 'Understand what adding a user to the docker group grants before doing it: it is equivalent to root. Anyone in that group can start a container that mounts the host filesystem and read or write anything on it.' 'This is presented everywhere as a convenience step and it is a privilege grant. On a shared or production machine it deserves a decision, not a reflex.' manual || true

if step 3 'Where that is acceptable, add the user and start a new session.' '' cmd 'sudo usermod -aG docker $USER' 'newgrp docker' 'docker info | head -5'; then
  sudo usermod -aG docker $USER
  newgrp docker
  docker info | head -5
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 3 failed. The rest of the fix may depend on it." >&2
  fi
fi

if step 4 'Where it is not, use sudo for docker commands, or run rootless Docker, which gives the same convenience without host-level privilege.' '' cmd 'dockerd-rootless-setuptool.sh install' 'export DOCKER_HOST=unix:///run/user/$(id -u)/docker.sock'; then
  dockerd-rootless-setuptool.sh install
  export DOCKER_HOST=unix:///run/user/$(id -u)/docker.sock
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 4 failed. The rest of the fix may depend on it." >&2
  fi
fi

if step 5 'For Podman, no daemon and no group are involved at all -- rootless is the default.' '' cmd 'podman info | head -5'; then
  podman info | head -5
  if [ $? -ne 0 ]; then
    failed=$((failed+1))
    echo "  Step 5 failed. The rest of the fix may depend on it." >&2
  fi
fi

rule "  Confirm it worked"
prose 'docker ps works as the intended user.'
if [ "$DRYRUN" = "0" ]; then
  docker ps
fi

rule
if [ "$failed" -gt 0 ]; then
  echo "  Finished with $failed failed step(s)."
  echo "  Read the full write-up at https://jbtecwiz.com/support/lnx-ctr-daemon"
else
  echo "  Finished."
fi
echo
prose 'To undo: sudo gpasswd -d $USER docker removes the group membership.'
rule