repositories

Last updated: 2025-10-30 01:15:02.763770 File source: link on GitLab

db

Specification

Description

The db package contains the configuration and functionality of database used by the DMS

Structure and Organisation

Here is quick overview of the contents of this pacakge:

Files

README: Current file which is aimed towards developers who wish to use and modify the database functionality.
generic_repository: This file defines the interface defining the main methods for db pacakge. It is designed using generic types and can be adapted to specific data type as needed.
generic_entity_repository: This file contains the interface for those databases which will hold only a single record.
deployment: This file specifies a database interface having types.DeploymentRequestFlat data type.
elk_stats: This file specifies a database interface having types.RequestTracker data type.
errors: This file specifies the different types of errors.
firecracker: This file specifies a database interface having types.VirtualMachine data type.
machine: This file defines database interfaces of various data types.
utils: This file contains some utility functions with respect to database operations.
utils_test: This file contains unit tests for functions defined in utils.go file.

Subpackages

clover: This folder contains CloverDB database implementation.

Class Diagram

The class diagram for the db package is shown below.

Source file

db Class diagram

Rendered from source file

!$rootUrlGitlab = "https://gitlab.com/nunet/device-management-service/-/raw/main"
!$packageRelativePath = "/db/repositories"
!$packageUrlGitlab = $rootUrlGitlab + $packageRelativePath
 
!include $packageUrlGitlab/specs/class_diagram.puml

Functionality

There are two types of interfaces defined to cover database operations:

GenericRepository
GenericEntityRepository

These interfaces are described below.

GenericRepository Interface

GenericRepository interface defines basic CRUD operations and standard querying methods. It is defined with generic data types. This allows it to be used for any data type.

interface definition: type GenericRepository[T ModelType] interface

The methods of GenericRepository are as follows:

Create

signature: Create(ctx context.Context, data T) -> (T, error)
input #1: Go context
input #2: Data to be added to the database. It should be of type used to initialize the repository
output (success): Data type used to initialize the repository
output (error): error message

Create function adds a new record to the database.

Get

signature: Get(ctx context.Context, id interface{}) -> (T, error)
input #1: Go context
input #2: Identifier of the record. Can be any data type
output (success): Data with the identifier provided. It is of type used to initialize the repository
output (error): error message

Get function retrieves a record from the database by its identifier.

Update

signature: Update(ctx context.Context, id interface{}, data T) -> (T, error)
input #1: Go context
input #2: Identifier of the record. Can be any data type
input #3: New data of type used to initialize the repository
output (success): Updated record of type used to initialize the repository
output (error): error message

Update function modifies an existing record in the database using its identifier.

Delete

signature: Delete(ctx context.Context, id interface{}) -> error
input #1: Go context
input #2: Identifier of the record. Can be any data type
output (success): None
output (error): error message

Delete function deletes an existing record in the database using its identifier.

Find

signature: Find(ctx context.Context, query Query[T]) -> (T, error)
input #1: Go context
input #2: Query of type db.query
output (success): Result of query having the data type used to initialize the repository
output (error): error message

Find function retrieves a single record from the database based on a query.

FindAll

signature: FindAll(ctx context.Context, query Query[T]) -> ([]T, error)
input #1: Go context
input #2: Query of type db.query
output (success): Lists of records based on query result. The data type of each record will be what was used to initialize the repository
output (error): error message

FindAll function retrieves multiple records from the database based on a query.

GetQuery

signature: GetQuery() -> Query[T]
input: None
output: Query of type db.query

GetQuery function returns an empty query instance for the repository's type.

GenericEntityRepository Interface

GenericEntityRepository defines basic CRUD operations for repositories handling a single record. It is defined with generic data types. This allows it to be used for any data type.

interface definition: type GenericEntityRepository[T ModelType] interface

The methods of GenericEntityRepository are as follows:

Save

signature: Save(ctx context.Context, data T) -> (T, error)
input #1: Go context
input #2: Data to be saved of type used to initialize the database
output (success): Updated record of type used to initialize the repository
output (error): error message

Save function adds or updates a single record in the repository

Get

signature: Get(ctx context.Context) -> (T, error)
input: Go context
output (success): Record of type used to initialize the repository
output (error): error message

Get function retrieves the single record from the database.

Clear

signature: Clear(ctx context.Context) -> error
input: Go context
output (success): None
output (error): error

Clear function removes the record and its history from the repository.

History

signature: History(ctx context.Context, qiery Query[T]) -> ([]T, error)
input #1: Go context
input #2: query of type db.query
output (success):List of records of repository's type
output (error): error

History function retrieves previous records from the repository which satisfy the query conditions.

GetQuery

signature: GetQuery() -> Query[T]
input: None
output: New query of type db.query

GetQuery function returns an empty query instance for the repository's type.

Data Types

db.Query: This contains parameters related to a query that is passed to the database.

type Query[T any] struct {
	Instance   T                // Instance is an optional object of type T used to build conditions from its fields.
	Conditions []db.QueryCondition // Conditions represent the conditions applied to the query.
	SortBy     string           // SortBy specifies the field by which the query results should be sorted.
	Limit      int              // Limit specifies the maximum number of results to return.
	Offset     int              // Offset specifies the number of results to skip before starting to return data.
}

db.QueryCondition: This contains parameters defining a query condition.

type QueryCondition struct {
	Field    string      // Field specifies the database or struct field to which the condition applies.
	Operator string      // Operator defines the comparison operator (e.g., "=", ">", "<").
	Value    interface{} // Value is the expected value for the given field.
}

Testing

The unit tests for utility functions are defined in utils_test.go. Refer to *_test.go files for unit tests of various implementations covered in subpackages.

Proposed Functionality / Requirements

List of issues

All issues that are related to the implementation of db package can be found below. These include any proposals for modifications to the package or new functionality needed to cover the requirements of other packages.

db package implementation

References

Previousclover Nextdms

Last updated 22 hours ago

db

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