refactor(database): move user logic into separate package

[jbrockopp]

Based off of #574

This change continues the refactor effort initially introduced in the above PR.

This adds a new user package to the github.com/go-vela/server/database package.

This contains a UserService interface declaring all functions necessary for user based interactions with the database:

server/database/user/service.go

Lines 11 to 45 in b2350a9

	// UserService represents the Vela interface for user
	// functions with the supported Database backends.
	//
	// nolint: revive // ignore name stutter
	type UserService interface {
	// User Data Definition Language Functions
	//
	// https://en.wikipedia.org/wiki/Data_definition_language
	// CreateUserIndexes defines a function that creates the indexes for the users table.
	CreateUserIndexes() error
	// CreateUserTable defines a function that creates the users table.
	CreateUserTable(string) error
	// User Data Manipulation Language Functions
	//
	// https://en.wikipedia.org/wiki/Data_manipulation_language
	// CountUsers defines a function that gets the count of all users.
	CountUsers() (int64, error)
	// CreateUser defines a function that creates a new user.
	CreateUser(*library.User) error
	// DeleteUser defines a function that deletes an existing user.
	DeleteUser(*library.User) error
	// GetUser defines a function that gets a user by ID.
	GetUser(int64) (*library.User, error)
	// GetUserForName defines a function that gets a user by name.
	GetUserForName(string) (*library.User, error)
	// ListUsers defines a function that gets a list of all users.
	ListUsers() ([]*library.User, error)
	// ListLiteUsers defines a function that gets a lite list of users.
	ListLiteUsers(int, int) ([]*library.User, int64, error)
	// UpdateUser defines a function that updates an existing user.
	UpdateUser(*library.User) error
	}

This package also contains the engine which implements the above service interface:

server/database/user/user.go

Lines 25 to 39 in b2350a9

	// engine represents the user functionality that implements the UserService interface.
	engine struct {
	// engine configuration settings used in user functions
	config *config
	// gorm.io/gorm database client used in user functions
	//
	// https://pkg.go.dev/gorm.io/gorm#DB
	client *gorm.DB
	// sirupsen/logrus logger used in user functions
	//
	// https://pkg.go.dev/github.com/sirupsen/logrus#Entry
	logger *logrus.Entry
	}

This engine contains no raw SQL queries for integrating with the users table.

Instead, we leverage our DB library's (https://gorm.io/) agnostic abstraction for integrating with that table.

[codecov]

Codecov Report

Merging #663 (9445022) into master (4c3147f) will increase coverage by 0.20%.
The diff coverage is 78.66%.

@@            Coverage Diff             @@
##           master     #663      +/-   ##
==========================================
+ Coverage   54.94%   55.14%   +0.20%     
==========================================
  Files         195      201       +6     
  Lines       15962    15882      -80     
==========================================
- Hits         8770     8758      -12     
+ Misses       6818     6748      -70     
- Partials      374      376       +2     

Impacted Files	Coverage Δ
api/authenticate.go	0.00% <0.00%> (ø)
api/metrics.go	0.00% <0.00%> (ø)
api/user.go	0.00% <0.00%> (ø)
database/user/user.go	51.72% <51.72%> (ø)
database/sqlite/sqlite.go	60.75% <66.66%> (+1.43%)	⬆️
database/postgres/postgres.go	60.33% <72.72%> (+1.75%)	⬆️
database/user/create.go	76.00% <76.00%> (ø)
database/user/update.go	76.00% <76.00%> (ø)
database/user/list_lite.go	76.31% <76.31%> (ø)
database/user/list.go	78.04% <78.04%> (ø)
... and 12 more

[cognifloyd]

Maybe point out in the docstrings ListUsers and ListLiteUsers differ (what makes it "Lite").
It looks like Lite just slips decrypting fields, right? Anything else?

Other than that, it looks good to me.

[jbrockopp]

@cognifloyd the ListLiteUsers() function only returns the id and name fields (Select):

server/database/user/list_lite.go

Lines 38 to 44 in a3798c3

	err = e.client.
	Table(constants.TableUser).
	Select("id", "name").
	Limit(perPage).
	Offset(offset).
	Find(&u).
	Error

This function is called when someone sends a GET request to the /api/v1/users endpoint.

The ListUsers() function returns everything:

server/database/user/list.go

Lines 34 to 37 in a3798c3

	err = e.client.
	Table(constants.TableUser).
	Find(&u).
	Error

This function is called when someone sends a GET request to the /api/v1/admin/users endpoint.

NOTE: The ListUsers() function can only be used by platform admins.

Do you have thoughts on what kind of changes you'd like to see regarding the function comments?

[cognifloyd]

Maybe something like this?

[kneal]

LGTM 🐬

[ecrupper]

LGTM - really like this new pattern