DB

A Go package to handle database connections.

This package is a convenience wrapper around other libraries and currently supports databases utilising the following protocols:

1. MySQL (github.com/go-sql-driver/mysql)
2. PostgreSQL (github.com/lib/pq)
3. MSSQL (github.com/denisenkom/go-mssqldb)

• Github: https://github.com/usvc/go-db
• Gitlab: https://gitlab.com/usvc/modules/go/db

The main database tool by usvc can be found at github.com/usvc/db if that's what you were looking for

• DB
• Usage
  • Importing
  • Creating a new database connection
  • Creating a new, named database connection
  • Importing an existing connection
  • Verifying a connection works
  • Retrieving a database connection
  • Closing a database connection
  • Closing all connections
• Configuration
  • db.Options
• Development Runbook
  • Getting Started
  • Continuous Integration (CI) Pipeline
    • On Github
      • Releasing
    • On Gitlab
      • Version Bumping
      • DockerHub Publishing
• Licensing

---

Usage

Importing

import "github.com/usvc/go-db"

Creating a new database connection

The following registers a new connection instance (but does not estabish a connection):

if err := db.Init(Options{
  Username: "user",
  Password: "password",
  Database: "schema",
  Hostname: "localhost",
  Port:     3306,
}); err != nil {
  log.Printf("an error occurred while creating the connection: %s", err)
}

Creating a new, named database connection

The following registers a new connection instance (but does not estabish a connection) named "my-connection":

if err := db.Init(Options{
  ConnectionName: "my-connection",
  Username: "user",
  Password: "password",
  Database: "schema",
  Hostname: "localhost",
  Port:     3306,
}); err != nil {
  log.Printf("an error occurred while creating the connection: %s", err)
}

Importing an existing connection

The following imports an existing *sql.DB connection and names it "connection-name"

var existingConnection *sql.DB
// ... initialise `existingConnection` by other means ...
if err := db.Import(existingConnection, "connection-name"); err != nil {
  log.Printf("connection 'connection-name' seems to already exist: %s\n", err)
}

Verifying a connection works

The following checks if the connection instance named "existing-connection" can establish a connection to the database server:

var existingConnection *sql.DB
// ... initialise `existingConnection` by other means ...
if err := db.Check("existing-connection"); err != nil {
  log.Printf("connection 'existing-connection' could not connect: %s\n", err)
}

Retrieving a database connection

The following retrieves the default *sql.DB connection instance:

// retrieve the 'default' connection
connection := db.Get()
if connection == nil {
  log.Println("connection 'default' does not exist")
}

The following retrieves the *sql.DB connection instance named "my-connection":

// retrieve the connection with name 'my-connection'
connection := db.Get("my-connection")
if connection == nil {
  log.Println("connection 'my-connection' does not exist")
}

Closing a database connection

The following closes the default database connection:

// ... run db.Init ...
if err := db.Close(); err != nil {
  log.Println("the default connection could not be closed")
}

The following closes the database connection named "my-connection":

// ... run db.Init for a connection named 'my-connection'...
if err := db.Close("my-connection"); err != nil {
  log.Println("the connection named 'my-connection' could not be closed")
}

Closing all connections

The following closes all database connections:

// ... run db.Init for a connection named 'my-connection'...
if err := db.Close("my-connection"); err != nil {
  for i := 0; i < len(err); i++ {
    log.Println(err[i])
  }
}

---

Configuration

db.Options

• ConnectionName string: Defines a local name of the connection. Defaults to "default"
• Hostname string: Defines the hostname where the database service can be reached. Defaults to "127.0.0.1"
• Port string: Defines the port which the database service is listening on. Defaults to uint16(3306)
• Username string: Defines the username of the user used to login to the database server. Defaults to "user"
• Password string: Defines the password of the user represented in the Username property. Defaults to "password"
• Database string: Defines the name of the database schema to use. Defaults to "database"
• Driver string: Defines the database driver to use. One of db.DriverMySQL, db.DriverPostgreSQL, or db.DriverMSSQL. Defaults to db.DriverMySQL
• Params map[string]string: Defines connection parameters to use in the data source name (DSN).

---

Development Runbook

Getting Started

1. Clone this repository
2. Run make deps to pull in external dependencies
3. Write some awesome stuff
4. Run make test to ensure unit tests are passing
5. Push

Continuous Integration (CI) Pipeline

On Github

Github is used to deploy binaries/libraries because of it's ease of access by other developers.

Releasing

Releasing of the binaries can be done via Travis CI.

1. On Github, navigate to the tokens settings page (by clicking on your profile picture, selecting Settings, selecting Developer settings on the left navigation menu, then Personal Access Tokens again on the left navigation menu)
2. Click on Generate new token, give the token an appropriate name and check the checkbox on public_repo within the repo header
3. Copy the generated token
4. Navigate to travis-ci.org and access the cooresponding repository there. Click on the More options button on the top right of the repository page and select Settings
5. Scroll down to the section on Environment Variables and enter in a new NAME with RELEASE_TOKEN and the VALUE field cooresponding to the generated personal access token, and hit Add

On Gitlab

Gitlab is used to run tests and ensure that builds run correctly.

Version Bumping

1. Run make .ssh
2. Copy the contents of the file generated at ./.ssh/id_rsa.base64 into an environment variable named DEPLOY_KEY in Settings > CI/CD > Variables
3. Navigate to the Deploy Keys section of the Settings > Repository > Deploy Keys and paste in the contents of the file generated at ./.ssh/id_rsa.pub with the Write access allowed checkbox enabled

• DEPLOY_KEY: generate this by running make .ssh and copying the contents of the file generated at ./.ssh/id_rsa.base64

DockerHub Publishing

1. Login to https://hub.docker.com, or if you're using your own private one, log into yours
2. Navigate to your security settings at the /settings/security endpoint
3. Click on Create Access Token, type in a name for the new token, and click on Create
4. Copy the generated token that will be displayed on the screen
5. Enter the following varialbes into the CI/CD Variables page at Settings > CI/CD > Variables in your Gitlab repository:

• DOCKER_REGISTRY_URL: The hostname of the Docker registry (defaults to docker.io if not specified)
• DOCKER_REGISTRY_USERNAME: The username you used to login to the Docker registry
• DOCKER_REGISTRY_PASSWORD: The generated access token

---

Licensing

Code in this package is licensed under the MIT license (click to see full text))