/Go Engineering/Phase 8

Phase 8Days 36-40

PostgreSQL, Transactions & Authentication

database/sql, migrations, SQL-first repositories, sessions, and authorization

Phase Goal

Persist real application state safely and enforce authentication and authorization server-side.

Progress

Notes

Open the written lectures for this course before checking off the phase topics.

Projects

Laboratory Sample Custody API

Day 36: PostgreSQL & database/sql

Define sql.DB as a concurrent connection pool in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when sql.DB as a concurrent connection pool is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for sql.DB as a concurrent connection pool and fix it deliberately

Define Drivers, PingContext, and pool configuration in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Drivers, PingContext, and pool configuration is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Drivers, PingContext, and pool configuration and fix it deliberately

Define QueryRowContext, QueryContext, Scan, and rows.Close in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when QueryRowContext, QueryContext, Scan, and rows.Close is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for QueryRowContext, QueryContext, Scan, and rows.Close and fix it deliberately

Define Prepared statements and parameterized SQL in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Prepared statements and parameterized SQL is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Prepared statements and parameterized SQL and fix it deliberately

Day 37: Schema Design, Migrations & Repositories

Define Keys, constraints, indexes, and timestamps in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Keys, constraints, indexes, and timestamps is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Keys, constraints, indexes, and timestamps and fix it deliberately

Define Forward migrations and reproducible environments in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Forward migrations and reproducible environments is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Forward migrations and reproducible environments and fix it deliberately

Define Repository boundaries without hiding SQL in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Repository boundaries without hiding SQL is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Repository boundaries without hiding SQL and fix it deliberately

Define sqlc awareness and compile-time query shapes in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when sqlc awareness and compile-time query shapes is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for sqlc awareness and compile-time query shapes and fix it deliberately

Day 38: Transactions, Isolation & Allocation Conflicts

Define sql.Tx lifecycle and rollback safety in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when sql.Tx lifecycle and rollback safety is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for sql.Tx lifecycle and rollback safety and fix it deliberately

Define Isolation levels and concurrent anomalies in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Isolation levels and concurrent anomalies is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Isolation levels and concurrent anomalies and fix it deliberately

Define Row locks, unique constraints, and atomic updates in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Row locks, unique constraints, and atomic updates is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Row locks, unique constraints, and atomic updates and fix it deliberately

Define Idempotency keys and retryable transaction failures in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Idempotency keys and retryable transaction failures is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Idempotency keys and retryable transaction failures and fix it deliberately

Day 39: Sessions, Passwords & Authorization

Define Password hashing and credential storage in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Password hashing and credential storage is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Password hashing and credential storage and fix it deliberately

Define Opaque sessions versus JWT trade-offs in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Opaque sessions versus JWT trade-offs is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Opaque sessions versus JWT trade-offs and fix it deliberately

Define Secure cookie flags, CSRF, and rotation in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Secure cookie flags, CSRF, and rotation is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Secure cookie flags, CSRF, and rotation and fix it deliberately

Define RBAC plus resource-level authorization in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when RBAC plus resource-level authorization is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for RBAC plus resource-level authorization and fix it deliberately

Day 40: Mini Project — Laboratory Sample Custody API

Define Users, samples, custody transfers, and disposal schema in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Users, samples, custody transfers, and disposal schema is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Users, samples, custody transfers, and disposal schema and fix it deliberately

Define Atomic handoff and chain-of-custody invariants in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Atomic handoff and chain-of-custody invariants is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Atomic handoff and chain-of-custody invariants and fix it deliberately

Define Session authentication and technician/supervisor policies in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Session authentication and technician/supervisor policies is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Session authentication and technician/supervisor policies and fix it deliberately

Define Project requirements, integration tests, and migrations in plain language and explain the problem it solvesTrace what the Go compiler or runtime does when Project requirements, integration tests, and migrations is usedWrite a tiny example, then apply it to a realistic backend taskDiagnose the beginner failure mode for Project requirements, integration tests, and migrations and fix it deliberately

Capstone

Laboratory Sample Custody API

Track biological samples from intake through technician handoffs, storage, analysis, and disposal while preserving an append-only custody history.

Concurrent handoffs cannot assign one sample to two custodians
Session auth plus sample- and role-level authorization
Reversible migrations and real-PostgreSQL integration tests

Phase Complete!

After this phase, you'll be able to:

sql.DB as a concurrent connection pool
Drivers, PingContext, and pool configuration
QueryRowContext, QueryContext, Scan, and rows.Close
Prepared statements and parameterized SQL
Keys, constraints, indexes, and timestamps
Forward migrations and reproducible environments
Repository boundaries without hiding SQL
sqlc awareness and compile-time query shapes

You can apply Phase 8 skills in a finished, explainable Go project.

Back to all phases

Phase Goal

Day 36: PostgreSQL & database/sql

sql.DB as a concurrent connection pool

Drivers, PingContext, and pool configuration

QueryRowContext, QueryContext, Scan, and rows.Close

Prepared statements and parameterized SQL

Day 37: Schema Design, Migrations & Repositories

Keys, constraints, indexes, and timestamps

Forward migrations and reproducible environments

Repository boundaries without hiding SQL

sqlc awareness and compile-time query shapes

Day 38: Transactions, Isolation & Allocation Conflicts

sql.Tx lifecycle and rollback safety

Isolation levels and concurrent anomalies

Row locks, unique constraints, and atomic updates

Idempotency keys and retryable transaction failures

Day 39: Sessions, Passwords & Authorization

Password hashing and credential storage

Opaque sessions versus JWT trade-offs

Secure cookie flags, CSRF, and rotation

RBAC plus resource-level authorization

Day 40: Mini Project — Laboratory Sample Custody API

Users, samples, custody transfers, and disposal schema

Atomic handoff and chain-of-custody invariants

Session authentication and technician/supervisor policies

Project requirements, constraints & review

Laboratory Sample Custody API

Phase Complete!