Vivek Shukla - Code Snippet

IndexNow Bulk URL Submit Using Curl

2026-04-26T00:00:00+00:00

IndexNow is a service which is used to inform search engines i.e. Bing, Naver, Seznam.cz, Yandex and Yep, about the content updates. This improves indexing. More info</a>.

IndexNow API supports upto 10,000 links submission in a day.

Make sure to have a randomly generated key c3755574c3ae4c259262854b0f241ec8.txt</code> at the root of your website. Generate key here</a> </blockquote>
🔗</a>Payload</h2> payload.json</code> { "host": "example.com", "key": "random-key", "keyLocation": "https://example.com/random-key.txt", "urlList": [ "https://example.com/blog" ] }</code></pre>🔗</a>Curl</h2> curl -v -X POST https://api.indexnow.org/indexnow -H "Content-Type: application/json" -d @payload.json</code></pre>

PostgreSQL: Make Create/Drop Operations Infallible 2026-04-25T00:00:00+00:00 While creating a database table, column or index, if it already exist, postgres will throw the error and abort the whole operation. Using IF EXISTS</code> and IF NOT EXISTS</code> is a way to make them infallible. 🔗</a>Creating and Dropping Entire Tables</h3> Safe Create: CREATE TABLE IF NOT EXISTS users ( id UUID PRIMARY KEY, email VARCHAR(255) NOT NULL );</code></pre> Safe Drop: DROP TABLE IF EXISTS users;</code></pre>🔗</a>Adding and Removing Columns</h3> Safe Add Column: ALTER TABLE users ADD COLUMN IF NOT EXISTS phone_number VARCHAR(20);</code></pre> Safe Drop Column: ALTER TABLE users DROP COLUMN IF EXISTS phone_number;</code></pre>🔗</a>Dropping Constraints (Easy)</h3> Safe Drop Constraint: ALTER TABLE users DROP CONSTRAINT IF EXISTS unique_email_constraint;</code></pre>🔗</a>Adding Constraints (The Tricky One)</h3> To make adding a constraint truly infallible, we have to use a tiny bit of PostgreSQL logic called a DO</code> blocIt checks the database records first before trying to add the rule. Safe Add Constraint (using a DO block): DO $$ BEGIN -- Check if the constraint name already exists IF NOT EXISTS ( SELECT 1 FROM pg_constraint WHERE conname = 'unique_email_constraint' ) THEN -- If it does not exist, add it ALTER TABLE users ADD CONSTRAINT unique_email_constraint UNIQUE (email); END IF; END $$;</code></pre>🔗</a>Custom Types and Enums (Bonus)</h3> Safe Drop Type: DROP TYPE IF EXISTS job_status_enum;</code></pre> Safe Create Type: (Postgres does not have CREATE TYPE IF NOT EXISTS</code>, so we use another DO</code> block) DO $$ BEGIN IF NOT EXISTS (SELECT 1 FROM pg_type WHERE typname = 'job_status_enum') THEN CREATE TYPE job_status_enum AS ENUM ('submitted', 'pending', 'completed'); END IF; END $$;</code></pre> UFW Cheat Sheet 2025-09-09T00:00:00+00:00 🔗</a>Check status</h2> sudo ufw status # or sudo ufw status verbose # or sudo ufw status numbered</code></pre>🔗</a>Delete value based on number:</h2> sudo ufw delete 5</code></pre>🔗</a>Allow port</h2> sudo ufw allow 22/tcp</code></pre>🔗</a>Deny port</h2> sudo ufw deny 80/tcp</code></pre>🔗</a>Allow from ip address or subnet</h2> sudo ufw allow from 10.22.96.0/20</code></pre>🔗</a>Allow from ip address to specific port</h2> sudo ufw allow from 10.22.96.0/20 proto tcp to any port 5432</code></pre>🔗</a>Disable ufw</h2> sudo ufw disable</code></pre>🔗</a>Block an ip address or subnet</h2> sudo ufw deny from 203.0.113.100</code></pre>🔗</a>Delete a rule</h2> sudo ufw delete allow from 203.0.113.101</code></pre>🔗</a>Allow incoming connection to a network interface</h2> sudo ufw allow in on eth0 from 203.0.113.102</code></pre> Cloud Init Script to Set-up Server 2025-09-05T00:00:00+00:00 Add this script to Cloud-init field while provisioning your VPS. Most cloud providers support this. This script will do following stuff: disable the root user</li> disable password authentication for SSH</li> update and upgrade ubuntu packages</li> create a new user named “ubuntu” add given public SSH key as authorized_key</code> for the user</li> Install and setup: Ufw: a firewall with open ports 22, 80 and 443</li> fail2ban: to protect against brute-force login attempt</li> unattended-upgrades: to upgrade ubuntu packages</li> docker</li> </ul> </li> </ul> #cloud-config disable_root: true ssh_pwauth: false package_update: true package_upgrade: true timezone: Etc/UTC system_info: default_user: ssh_authorized_keys: [] lock_passwd: true packages: - ufw - fail2ban - unattended-upgrades runcmd: - echo $(date) > /start - passwd -l root - sed -i 's/^PasswordAuthentication yes/PasswordAuthentication no/' /etc/ssh/sshd_config - systemctl restart sshd - ufw default deny incoming - ufw default allow outgoing - ufw allow 22/tcp - ufw allow 80/tcp - ufw allow 443/tcp - ufw --force enable - systemctl enable fail2ban - systemctl start fail2ban - unattended-upgrade - curl -fsSL https://get.docker.com | sh - groupadd docker - usermod -aG docker ubuntu - echo $(date) > /end users: - name: ubuntu lock_passwd: true ssh_authorized_keys: - YOUR_SSH_PUBLIC_KEY sudo: ALL=(ALL) NOPASSWD:ALL groups: sudo shell: /bin/bash</code></pre> Deploy Systemd Service Behind Nginx with TLS 2025-09-04T00:00:00+00:00 🔗</a>Systemd Service</h2> sudo tee /etc/systemd/system/YOUR_SERVICE_NAME.service << 'EOF' [Unit] Description=YOUR_SERVICE_NAME After=network.target [Service] ExecStart=/executable/location WorkingDirectory=/dir/where/program/can/read-write/data Restart=on-failure RestartSec=5s StartLimitIntervalSec=300 StartLimitBurst=5 User=ubuntu Group=ubuntu [Install] WantedBy=multi-user.target EOF</code></pre> Start command: sudo systemctl daemon-reload sudo systemctl enable YOUR_SERVICE_NAME sudo systemctl start YOUR_SERVICE_NAME</code></pre> Other commands: # see logs sudo journalctl -u YOUR_SERVICE_NAME -f # restart sudo systemctl restart YOUR_SERVICE_NAME # when service file is updated sudo systemctl daemon-reload</code></pre>🔗</a>Nginx Reverse Proxy</h2> sudo tee /etc/nginx/sites-available/YOUR_DOMAIN << 'EOF' map $http_upgrade $connection_upgrade { default upgrade; '' close; } upstream server_list { server localhost:8000; keepalive 32; } server { listen 80; # IPv4 listen [::]:80; # IPv6 server_name YOUR_DOMAIN; # Hide server information headers server_tokens off; # Enable gzip compression gzip on; gzip_disable "msie6"; gzip_vary on; gzip_proxied any; gzip_comp_level 6; gzip_buffers 16 8k; gzip_min_length 1024; gzip_types application/atom+xml application/geo+json application/javascript application/x-javascript application/json application/ld+json application/manifest+json application/rdf+xml application/rss+xml application/xhtml+xml application/xml font/eot font/otf font/ttf image/svg+xml text/css text/javascript text/plain text/xml; # Buffer size optimization client_body_buffer_size 32k; client_header_buffer_size 2k; client_max_body_size 10M; large_client_header_buffers 4 2k; # Timeouts client_body_timeout 20; client_header_timeout 20; keepalive_timeout 65; send_timeout 20; # Proxy settings location / { include proxy_params; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $connection_upgrade; proxy_redirect off; proxy_buffering on; proxy_buffer_size 16k; proxy_buffers 8 16k; proxy_pass http://server_list; # Additional proxy timeouts proxy_connect_timeout 60s; proxy_send_timeout 120s; proxy_read_timeout 120s; } # Security headers add_header X-Content-Type-Options "nosniff" always; add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always; } EOF</code></pre> Create Symlink sudo ln -s /etc/nginx/sites-available/YOUR_DOMAIN /etc/nginx/sites-enabled/</code></pre> Checks Nginx configuration sudo nginx -t</code></pre> Restart Nginx sudo systemctl restart nginx</code></pre>🔗</a>Letsencrypt SSL</h2> Installing certbot</code> to install TLS certificate sudo apt remove certbot sudo snap install core; sudo snap refresh core sudo snap install --classic certbot sudo ln -s /snap/bin/certbot /usr/bin/certbot sudo certbot --nginx -d YOUR_DOMAIN</code></pre> Ed25519 Key Pair Generation in Rust 2025-06-20T00:00:00+00:00 🔗</a>Cargo.toml</h2> [dependencies] ssh-key = { version = "0.6", features = ["ed25519", "rsa"] }</code></pre>🔗</a>main.rs</h2> use ssh_key::{LineEnding, PrivateKey, rand_core::OsRng}; use std::fs; use std::path::PathBuf; use std::time::Instant; fn generate_ed25519_key_pair( path_prefix: &str, comment: &str, ) -> Result<(), Box<dyn std::error::Error>> { let timer = Instant::now(); let mut private_key = PrivateKey::random(&mut OsRng, ssh_key::Algorithm::Ed25519)?; private_key.set_comment(comment); let private_key_bytes = private_key.to_openssh(LineEnding::LF)?; let public_key_bytes = private_key.public_key().to_openssh()?; let private_path = PathBuf::from(format!("{}_ed25519", path_prefix)); let public_path = PathBuf::from(format!("{}_ed25519.pub", path_prefix)); fs::write(&private_path, private_key_bytes)?; fs::write(&public_path, public_key_bytes)?; println!("Generated Ed25519 key pair:"); println!("Private key: {}", private_path.display()); println!("Public key: {}", public_path.display()); println!("Time Elapsed: {}ms", timer.elapsed().as_millis()); Ok(()) } fn main() { match generate_ed25519_key_pair("id", "example@localhost") { Ok(_) => println!("Successfully generated Ed25519 key pair without passphrase."), Err(e) => eprintln!("Error generating Ed25519 key pair: {}", e), } }</code></pre> Rust Release Build & Publish 2025-06-15T00:00:00+00:00 docker run --rm -it ubuntu /bin/bash</code></pre># Environment Variables # | Key | Purpose | # | --------------------- | ---------------------------------------------------------------- | # | DEPLOY_KEY | Private SSH key (public key must be added in Github) | # | REPO_URL | Github repository url (ssh) | # | BINARY_NAME | Binary name in Cargo.toml | # | RCLONE_CONFIG_CONTENT | Contents of the Rclone config. Name must be "remote_destination" | # | RCLONE_COPY_PATH | Path of the bucket where you want to copy the file | # Rclone Config Example # ``` # [remote_destination] # type = s3 # provider = Other # access_key_id = # secret_access_key = # endpoint = # acl = public-read # ``` export DEBIAN_FRONTEND=noninteractive apt update apt install -y build-essential libssl-dev pkg-config curl git openssh-client unzip curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y . "$HOME/.cargo/env" curl https://rclone.org/install.sh | bash export RCLONE_CONFIG="/rclone.conf" echo "$RCLONE_CONFIG_CONTENT" > $RCLONE_CONFIG mkdir -p /root/.ssh echo "$DEPLOY_KEY" > /root/.ssh/deploy_key chmod 600 /root/.ssh/deploy_key ssh-keyscan github.com >> /root/.ssh/known_hosts chmod 600 /root/.ssh/known_hosts mkdir -p /app GIT_SSH_COMMAND="ssh -i /root/.ssh/deploy_key" git clone $REPO_URL /app cd /app FULL_NAME=$BINARY_NAME-$(uname -s | tr '[:upper:]' '[:lower:]')-$(uname -m | sed -e 's/x86_64/amd64/' -e 's/armv6l/arm/' -e 's/armv7l/arm/' -e 's/aarch64/arm64/') cargo build --release && \ cp target/release/$BINARY_NAME $FULL_NAME rclone copy "$FULL_NAME" remote_destination:"$RCLONE_COPY_PATH"</code></pre> Deploy OpenObserve binary behind Nginx on Ubuntu 2025-06-09T00:00:00+00:00 Quickstart guide</a> by OpenObserve. 🔗</a>Installing OpenObserve</h2> Download binary: mkdir ~/openobserve && cd $_ curl -L https://raw.githubusercontent.com/openobserve/openobserve/main/download.sh | sh chmod +x openobserve</code></pre> Create Environment file tee openobserve.env << 'EOF' # Data directory for OpenObserve. This is crucial for local storage. ZO_DATA_DIR="/home/ubuntu/openobserve/data" # The port OpenObserve will listen on (default is 5080) ZO_PORT=5080 # The root user email and password for initial login. # CHANGE THESE TO SECURE VALUES! ZO_ROOT_USER_EMAIL="admin@example.com" ZO_ROOT_USER_PASSWORD="SecurePassword123" ZO_META_STORE="sqlite" ZO_WEB_URL="https://your-domain # disabling OpenObserve's telemetry to their server ZO_TELEMETRY=false EOF sudo chmod 600 openobserve.env</code></pre> Creating systemd service sudo tee /etc/systemd/system/openobserve.service << 'EOF' [Unit] Description=OpenObserve Observability Platform After=network-online.target Wants=network-online.target [Service] # Service type: 'simple' means the process will be the main process Type=simple User=ubuntu Group=ubuntu WorkingDirectory=/home/ubuntu/openobserve EnvironmentFile=/home/ubuntu/openobserve/openobserve.env ExecStart=/home/ubuntu/openobserve/openobserve Restart=on-failure RestartSec=5s # Limit the number of open file descriptors, important for high-concurrency apps. # Adjust as needed based on your expected load. LimitNOFILE=65536 # Redirect standard output and error to systemd journal. StandardOutput=journal StandardError=journal # How long to wait before forcefully terminating the service on stop. TimeoutStopSec=30s [Install] # This unit should be enabled for multi-user systems. # Allows it to start automatically on boot. WantedBy=multi-user.target EOF</code></pre> Start service # Reload systemd daemon to pick up the new service file sudo systemctl daemon-reload # Enable the service to start on boot sudo systemctl enable openobserve # Start the OpenObserve service sudo systemctl start openobserve</code></pre> Check the service status and logs # Check service status sudo systemctl status openobserve # View logs sudo journalctl -u openobserve -f</code></pre>🔗</a>Reverse Proxy - Nginx</h2> Install Nginx sudo apt -y install nginx</code></pre>sudo tee /etc/nginx/sites-available/openobserve << 'EOF' map $http_upgrade $connection_upgrade { default upgrade; '' close; } server { listen 80; # IPv4 listen [::]:80; # IPv6 server_name your-domain; # Hide server information headers server_tokens off; # Enable gzip compression gzip on; gzip_vary on; gzip_proxied any; gzip_comp_level 6; gzip_min_length 1024; # Only gzip if size is at least 1KB gzip_types text/plain text/css text/xml application/json application/javascript application/rss+xml application/atom+xml image/svg+xml; # Proxy settings location / { include proxy_params; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $connection_upgrade; proxy_redirect off; proxy_pass http://localhost:5080; } location /metrics { # allow 192.168.1.100; # <--- REPLACE WITH YOUR MONITORING SERVER'S IP deny all; } # Security headers add_header X-Content-Type-Options "nosniff" always; add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always; } EOF</code></pre>sudo ln -s /etc/nginx/sites-available/openobserve /etc/nginx/sites-enabled/ # test nginx conf sudo nginx -t</code></pre>sudo systemctl restart nginx</code></pre> Afterwards, to gracefully restart nginx, do this: sudo nginx -s reload # OR sudo systemctl reload nginx</code></pre>🔗</a>TLS Installation</h2> sudo snap install core; sudo snap refresh core sudo apt remove certbot sudo snap install --classic certbot sudo ln -s /snap/bin/certbot /usr/bin/certbot sudo certbot --nginx -d your-domain</code></pre> docker buildx: Multi-platform Builds 2025-04-23T00:00:00+00:00 Tested on: Ubuntu 22.04 LTS Docker Version: 28.1.1 Docker Buildx Version: v0.23.0 Documentation: Multi-platform Builds</a> # check if buildx is installed docker buildx version</code></pre># installing and registering QEMU docker run --privileged --rm tonistiigi/binfmt --install all</code></pre># create new build that runs in docker container docker buildx create --name mybuilder --driver docker-container</code></pre># switching to our builder docker buildx use mybuilder</code></pre># build and pushing image directly to image store (make sure you are logged in) docker buildx build --platform linux/amd64,linux/arm64 -t <username>/<image_name>:<tag> . --push</code></pre> Docker Image Publishing 2025-04-23T00:00:00+00:00 Login docker login --username <username> --password-stdin</code></pre> Build docker build . -t <image_name>:<tag></code></pre> Tag docker tag <image_name>:<tag> <username>/<image_name>:<tag></code></pre> Push docker push <username>/<image_name>:<tag></code></pre>

🔗</a>Delete a rule</h2>
`sudo</span> ufw delete allow from</span> 203.0.113.101</span></span></code></pre>`
🔗</a>Allow incoming connection to a network interface</h2>
`sudo</span> ufw allow in on eth0 from</span> 203.0.113.102</span></span></code></pre>`

🔗</a>Allow incoming connection to a network interface</h2>
`sudo</span> ufw allow in on eth0 from</span> 203.0.113.102</span></span></code></pre>`

Vivek Shukla - Code Snippet

IndexNow Bulk URL Submit Using Curl

🔗</a>Curl</h2>
`curl</span> -v -X</span> POST https://api.indexnow.org/indexnow</span> -H</span> "Content-Type: application/json"</span> -d</span> @payload.json</span></span></code></pre>`

PostgreSQL: Make Create/Drop Operations Infallible

UFW Cheat Sheet

Cloud Init Script to Set-up Server

Deploy Systemd Service Behind Nginx with TLS

Ed25519 Key Pair Generation in Rust

Rust Release Build & Publish

Deploy OpenObserve binary behind Nginx on Ubuntu

docker buildx: Multi-platform Builds

Docker Image Publishing