SnapDisk

SnapDisk is a small Java 21 Swing desktop app that takes one daily snapshot of disk space, stores timestamped records in PostgreSQL, and shows a table + a simple chart of used space over time.

Screenshot

Project layout

• src/ — Java source (packages: com.snapdisk.app, db, dao, model, util, tools)
• lib/ — third-party jars (Postgres JDBC, optional JFreeChart)
• bin/ — compiled classes (output)
• schema.sql — example DB schema

Dependencies

• Java 21
• PostgreSQL JDBC driver (place postgresql-*.jar in lib/)
• JFreeChart jars are optional (put them in lib/ if you want advanced charting)

Build

Compile all sources from the project root (handles spaces in the path):

mapfile -t JAVA_FILES < <(find src -name '*.java' -print0 | xargs -0 -n1 echo)
javac -d bin -sourcepath src -cp "lib/*" "${JAVA_FILES[@]}"

Run

• Quick launcher (preferred):

java -cp "bin:lib/*" com.snapdisk.app.Launcher

• Or use the helper script that compiles and runs with --no-db support:

./run.sh --no-db    # shows UI with sample data

DB setup (recommended)

Run these commands as a Postgres superuser to create the role, database and table used by the app. Adjust passwords as needed.

# create role
psql -U postgres -c "CREATE ROLE snapdisk_user LOGIN PASSWORD 'password';" || true

# create database owned by role
psql -U postgres -c "CREATE DATABASE snapdisk OWNER snapdisk_user;" || true

# create table and grant privileges
psql -U postgres -d snapdisk <<'SQL'
CREATE TABLE IF NOT EXISTS public.disk_snapshots (
	id SERIAL PRIMARY KEY,
	snapshot_date DATE NOT NULL UNIQUE,
	snapshot_time TIME NOT NULL,
	total_space BIGINT NOT NULL,
	free_space BIGINT NOT NULL,
	used_space BIGINT NOT NULL
);
ALTER TABLE public.disk_snapshots OWNER TO snapdisk_user;
GRANT USAGE, CREATE ON SCHEMA public TO snapdisk_user;
GRANT SELECT, INSERT, UPDATE, DELETE ON TABLE public.disk_snapshots TO snapdisk_user;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT, INSERT, UPDATE, DELETE ON TABLES TO snapdisk_user;
SQL

Notes:

• The project currently contains hardcoded DB credentials in src/com/snapdisk/db/Database.java. Change them before production use.

Tools

• Populate history (backfill recent days):

java -cp "bin:lib/*" com.snapdisk.tools.PopulateHistory 14

Features

• Automatic one-per-day snapshot on app start (saves total/free/used bytes)
• Table of snapshots (read-only)
• Chart plotting used space as percent of total (start & end labels only)
• Buttons: Clear Data (delete all DB rows) and Export PNG (save chart image)

Troubleshooting

• If the app reports schema/permission errors, run the DB setup SQL above as a superuser.
• If you prefer to try the UI without a DB, use ./run.sh --no-db or set SNAPDISK_NO_DB=true.

Next steps

• Improve persistence config (remove hardcoded credentials)
• Add scheduled snapshot (OS cron / systemd timer)
• Add export CSV and unit tests

Enjoy — open an issue or edit files if you want changes.