Deploy Script for My Node.JS app for zero-downtime (single server - no revert - only latest commit)

deploy-node.sh

#!/bin/bash

## SEE: http://pm2.keymetrics.io/docs/tutorials/capistrano-like-deployments
# 0. Folder Structure
#     -> /var/www/project_root
#         -> source
#         -> current -> symlink to latest release
#         -> versions
#             -> sha-of-commit
#         -> logs
#         -> config
#             -> pm2c.json


# STEPS REQUIRED
# __Initial Requirement__ (do it manually everytime)
# 0. pm2, node must be installed.
# 1. git clone the project and change its name to source.
# 2. add .env file or other config.
# 3. do npm install first time only for caching.


## CASE-1: User want to deploy new commit (using deploy command)
# 1. cd into source dir and get the commit sha of version you want.
# 2. if (dir doesn't exist with same commit)
#       -> create a new dir in project_root/versions, do npm prune & npm install & npm run build.
#    -> delete last symlink and create new symlink to this version.
# 3. Manually do pm2 reload/restart/start appname.

## CASE-2: User want to revert (or want to redeploy to specific commit) NOT POSSIBLE CURRENTLY.
# 1. get the commit from source dir according to revert number or default 1.
# 2. perform steps from CASE-1.

## CASE-3: User changed the .env file in source dir.
# 1. first delete the whole versions folder and do deploy.

## COMMANDS
# 1. deploy: Simply deploy using the latest commit from source folder.




set -e;

ROOT_PATH=${1:-"/var/www/imgsquash.com"};
# latest_commit=$(git rev-parse --verify --short HEAD);
# nth_commit=$(git rev-parse --verify --short @{$2});


log() {
    # ref: http://linuxcommand.org/lc3_adv_tput.php
    # set color green and bold text.
    tput bold; tput setaf 2; echo "  ○ $@"; tput sgr0;
}

abort() {
  echo
  echo "  $@" 1>&2
  echo
  exit 1
}



deploy() {
    # deploy to the latest version.
    local ref=$1;  # args of this function.
    local path=$ROOT_PATH;

    log "deploying";

    log "stashing all local changes if any";
    cd $path/source && git stash -u;
    test $? -eq 0 || abort stashed failed;

    # Fetch source.
    log "pulling updates";
    cd $path/source && git pull --all;
    test $? -eq 0 || abort pull failed;

    # Get latest commit sha
    log "getting latest sha commit";
    local latest_sha=$(git rev-parse --short --verify HEAD);

    # if directory doesn't exist
    if ! [ -d "$path/versions/$latest_sha" ]; then
        log "creating new sha dir on $path/versions"
        mkdir -p $path/versions/$latest_sha;
        test $? -eq 0 || abort directory created unsuccessful
        # using rsync instead of cp for fast copy. Don't forget trailing slash.
        rsync -aHW --stats $path/source/ $path/versions/$latest_sha;
        test $? -eq 0 || abort copy unsuccessful
        log "doing npm install and npm run build. Make sure .env file is there in source.";
        cd $path/versions/$latest_sha && npm install --unsafe-perm && npm run build || (rm -rf $path/versions/$latest_sha && abort npm install and build failed)
        # remove previous symlink to current and create the new one.
        ln -sfn $path/versions/$latest_sha $path/current
        test $? -eq 0 || abort symlink failed
    fi


}


# finally deploy.
deploy
#### END ####