MacOS positron update script. Script checks beta version from github releases and compare with current installed one

positron_update.sh

#!/usr/bin/env bash

set -e

# Function to log errors
log_error() {
    echo "ERROR: $1" >&2
}

# Function to log info
log_info() {
    echo "INFO: $1"
}

# Function to check if a command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Function to install jq if it's not present
install_jq() {
    if ! command_exists brew; then
        log_error "Homebrew is not installed. Please install Homebrew or jq manually."
        exit 1
    fi

    log_info "Attempting to install the 'jq' command-line tool..."
    if ! brew install jq; then
        log_error "Unable to install the 'jq' command-line tool. Please install 'jq' manually and try again."
        exit 1
    fi
}

# Function to get the current installed version of Positron
get_installed_version() {
    if [ -e "/Applications/Positron.app/Contents/Info.plist" ]; then
        version=$(/usr/libexec/PlistBuddy -c "Print CFBundleShortVersionString" "/Applications/Positron.app/Contents/Info.plist")
        echo "$version"
    else
        echo ""
    fi
}

# Function to compare versions
version_gt() {
    test "$(printf '%s\n' "$@" | sort -V | head -n 1)" != "$1"
}

# Check for jq
if ! command_exists jq; then
    install_jq
fi

log_info "Checking for Positron installation and updates."

# Check if Positron is installed
installed_version=$(get_installed_version)
if [ -z "$installed_version" ]; then
    log_info "Positron is not currently installed. Proceeding with installation of the latest version."
else
    log_info "Current installed version: $installed_version"
fi

# Fetch release information
response=$(curl -s "https://api.github.com/repos/posit-dev/positron/releases")
if [ $? -ne 0 ]; then
    log_error "Unable to fetch data from GitHub API."
    exit 1
fi

# Check if the response is valid JSON and contains the expected fields
if ! echo "$response" | jq -e '.[0].tag_name' > /dev/null 2>&1; then
    log_error "Invalid or unexpected response from GitHub API. Response: $response"
    exit 1
fi

latest_tag=$(echo "$response" | jq -r '.[0].tag_name')
latest_version=${latest_tag#v}  # Remove 'v' prefix if present

if [ -n "$installed_version" ] && ! version_gt "$latest_version" "$installed_version"; then
    log_info "You already have the latest version ($installed_version) installed."
    exit 0
fi

# Check if Positron is running
if pgrep -x "Positron" > /dev/null; then
    read -p "Positron is currently running. Close it before updating? (y/n): " answer
    if [[ $answer != [Yy]* ]]; then
        log_info "Update cancelled. Please close Positron and run the script again."
        exit 0
    fi
    killall Positron
fi

# Prepare for download and installation
tempdir=$(mktemp -d)
trap 'rm -rf "$tempdir"' EXIT

asset_url=$(echo "$response" | jq -r '.[0].assets[] | select(.name|test("dmg$")) | .browser_download_url')
if [ -z "$asset_url" ]; then
    log_error "Unable to find a DMG download URL in the GitHub API response."
    exit 1
fi

filename=$(basename "$asset_url")
destination="${tempdir}/${filename}"

log_info "Downloading ${filename}..."
if ! curl -L -o "$destination" "$asset_url"; then
    log_error "Unable to download Positron from GitHub."
    exit 1
fi

log_info "Installing ${filename}..."
volume_name=$(basename "$filename" .dmg)
volume_mount="/Volumes/${volume_name}"

if ! hdiutil attach -quiet "$destination"; then
    log_error "Failed to mount the disk image."
    exit 1
fi

log_info "Contents of mounted volume:"
ls -l "${volume_mount}"

if [ -d "${volume_mount}/Positron.app" ]; then
    log_info "Copying Positron.app to /Applications..."
    if ! sudo rsync -a --delete --info=progress2 "${volume_mount}/Positron.app" /Applications/; then
        log_error "Failed to copy Positron to /Applications. Checking permissions..."
        ls -l /Applications
        hdiutil detach -quiet "$volume_mount"
        exit 1
    fi
    log_info "Copy successful"
else
    log_error "Positron.app not found in mounted volume"
    hdiutil detach -quiet "$volume_mount"
    exit 1
fi


if ! hdiutil detach -quiet "$volume_mount"; then
    log_error "Failed to unmount the disk image."
    exit 1
fi

if [ ! -e "/Applications/Positron.app" ]; then
    log_error "Positron.app not found in /Applications after installation. Contents of /Applications:"
    ls -l /Applications
    exit 1
fi

# Set correct permissions for the Positron.app
sudo chown -R root:wheel /Applications/Positron.app
sudo chmod -R 755 /Applications/Positron.app


log_info "Successfully installed Positron ${latest_version}."
log_info "Positron.app should now be located in /Applications."