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backend

Last updated: 2024-09-17 21:08:34.684268 File source: link on GitLab

backend

Table of Contents

  1. Description

  2. Structure and Organisation

  3. Class Diagram

  4. Functionality

  5. Data Types

  6. Testing

  7. Proposed Functionality/Requirements

  8. References

Specification

Description

The backend sub package contains the actual implementation of the Nunet CLI commands.

Structure and Organisation

Here is quick overview of the contents of this directory:

  • README: Current file which is aimed towards developers who wish to use and modify the cmd functionality.

  • backend: This file defines various interfaces DMS backend service. These interfaces provide abstractions for functionalities like resource management, peer management, network management, logging, and file system access.

  • filesystem: This file implements FileSystem functionality using the standard os package. It provides functions for basic file operations like creating, opening, reading, writing, and deleting files and directories.

  • journal: This file implements a wrapper to go-systemd/sdjournal functionality. It wraps the sdjournal functionality providing access to systemd journal entries like adding filters, retrieving entries, and iterating through them.

  • libp2p: This file implements functionalites to clear incoming chat requests and decode a peer id.

  • network: This file implements a method to get network connections data.

  • resources: This file implements a method to get total capacity of the machine.

  • utils: This file implements utitlity functions for backend functionality.

  • wallet: This file contains methods to get wallet address for the user.

  • websocket: This file implements a WebSocket Client for establishing and managing WebSocket connections. It provides functions to initialize the connection, send/receive messages, and handle pings for maintaining the connection.

Class Diagram

The class diagram for the backend package is shown below.

Source file

backend Class diagram

Rendered from source file

!$rootUrlGitlab = "https://gitlab.com/nunet/device-management-service/-/raw/main"
!$packageRelativePath = "/cmd/backend"
!$packageUrlGitlab = $rootUrlGitlab + $packageRelativePath

!include $packageUrlGitlab/specs/class_diagram.puml

Functionality

ResourceManager interface

ResourceManager interface consists of following methods:

GetTotalProvisioned

  • signature: GetTotalProvisioned() *types.Provisioned

  • input: None

  • output: types.onboarding.Provisioned

GetTotalProvisioned returns the total capacity of the machine.

PeerManager interface

PeerManager interface abstracts libp2p functionality. It consists of following methods:

ClearIncomingChatRequests

  • signature: ClearIncomingChatRequests() error

  • input: None

  • output (error): error message

ClearIncomingChatRequests deletes all the incoming chat requests.

Decode

  • signature: Decode(s string) (peer.ID, error)

  • input: peerID string

  • output: decoded ID of type string

  • output (error): error message

Decode receives an encoded peerID string and returns the decoded ID.

WalletManager interface

WalletManager interface consists of following methods:

GetCardanoAddressAndMnemonic

  • signature: GetCardanoAddressAndMnemonic() (*types.BlockchainAddressPrivKey, error)

  • input: None

  • output: types.onboarding.BlockchainAddressPrivKey

  • output (error): error message

GetCardanoAddressAndMnemonic generates wallet on Cardano blockchain.

GetEthereumAddressAndPrivateKey

  • signature: GetEthereumAddressAndPrivateKey() (*types.BlockchainAddressPrivKey, error)

  • input: None

  • output: types.onboarding.BlockchainAddressPrivKey

  • output (error): error message

GetEthereumAddressAndPrivateKey generates wallet on Ethereum blockchain.

NetworkManager interface

NetworkManager interface abstracts connection on ports. It consists of following methods:

GetConnections

  • signature: GetConnections(kind string) ([]gonet.ConnectionStat, error)

  • input: type of connection

  • output: list of Connection Stats

  • output (error): error message

GetConnections returns the list of network connections opened on the machine.

Utility interface

Utility interface abstracts helper functions. It consists of following methods:

IsOnboarded

  • signature: IsOnboarded() (bool, error)

  • input: None

  • output: bool value showing whether the machine is onboarded or not.

  • output (error): error message

IsOnboarded checks whether machine is onboarded to Nunet.

ReadMetadataFile

  • signature: ReadMetadataFile() (*types.Metadata, error)

  • input: None

  • output: types.onboarding.Metadata

  • output (error): error message

ReadMetadataFile reads metadata file from the machine.

ResponseBody

  • signature: ResponseBody(c *gin.Context, method, endpoint, query string, body []byte) ([]byte, error)

  • input #1 : Context object

  • input #2 : HTTP method

  • input #3 : Endpoint URL

  • input #4 : Query parameters string

  • input #5 : Payload

  • output: byte value of the API Response

  • output (error): error message

ResponseBody executes an internal call to the DMS API endpoint and returns the response.

WebSocketClient interface

WebSocketClient interface provides functionality to chat commands. It consists of following methods:

Initialize

  • signature: Initialize(url string) error

  • input: target url

  • output: none

  • output (error): error message

Initialize initiates the dialing procedure to connect to the provided endpoint URL.

Close

  • signature: Close() error

  • input: none

  • output: none

  • output (error): error message

Close closes the active WebSocket connection.

ReadMessage

  • signature: ReadMessage(ctx context.Context, w io.Writer) error

  • input #1: Context object

  • input #1: io writer

  • output: none

  • output (error): error message

ReadMessage reads the incoming messages over a websocket connection.

WriteMessage

  • signature: WriteMessage(ctx context.Context, r io.Reader) error

  • input #1: Context object

  • input #1: io reader

  • output: none

  • output (error): error message

WriteMessage sends a message over a websocket connection.

Ping

  • signature: Ping(ctx context.Context, w io.Writer) error

  • input #1: Context object

  • input #1: io writer

  • output: none

  • output (error): error message

Ping sends WebSocket pings at 30 second intervals until the context is canceled or an error prevents sending the ping message.

Logger interface

Logger interface abstracts systemd journal entries. It consists of following methods:

AddMatch

  • signature: AddMatch(match string) error

  • input: filter pattern string

  • output: none

  • output (error): error message

AddMatch utilizes the input pattern string to filter the Systemd journal.

Close

  • signature: Close() error

  • input: none

  • output: none

  • output (error): error message

Close closes an open systemd journal.

GetEntry

  • signature: GetEntry() (*sdjournal.JournalEntry, error)

  • input: none

  • output: systemd journal entry

  • output (error): error message

GetEntry retrieves the next journal entry from the Systemd journal.

Next

  • signature: Next() (uint64, error)

  • input: none

  • output: byte offset for next entry

  • output (error): error message

Next advances the read pointer into the journal by one entry. This prepares the stage for the subsequent GetEntry method call.

FileSystem interface

FileSystem interface abstracts abstracts Afero/os calls. It consists of following methods:

Create

  • signature: Create(name string) (FileHandler, error)

  • input: file name

  • output: file object

  • output (error): error message

Create function creates a new file using the provided name.

MkdirAll

  • signature: MkdirAll(path string, perm os.FileMode) error

  • input #1: directory path

  • input #2: file mode and permission

  • output: none

  • output (error): error message

MkdirAll creates a new directory at the specified path.

OpenFile

  • signature: OpenFile(name string, flag int, perm os.FileMode) (FileHandler, error)

  • input #1: file name including the path

  • input #2: access mode

  • input #2: file permissions

  • output: file object

  • output (error): error message

OpenFile opens the file with the provided name.

ReadFile

  • signature: ReadFile(filename string) ([]byte, error)

  • input: file name

  • output: byte data of the file

  • output (error): error message

ReadFile reads the file with the provided name.

RemoveAll

  • signature: RemoveAll(path string) error

  • input: path

  • output: none

  • output (error): error message

RemoveAll deletes all the data at the provided path.

Walk

  • signature: Walk(root string, walkFn filepath.WalkFunc) error

    • input #1: root directory path

  • input #2: callback function

  • output: none

  • output (error): error message

Walk navigates a file hierarchy, instigating a callback function at each discovery.

FileHandler interface

FileSystem interface abstracts file interfaces shared between os and afero so that both can be used interchangeably. It consists of following methods:

io methods (Go standard library)

  • io.Closer

  • io.Reader

  • io.ReaderAt

  • io.Seeker

  • io.Writer

  • io.WriterAt

Stat

  • signature: Stat() (os.FileInfo, error)

  • input: none

  • output: file information

  • output (error): error message

Stat returns information about the file.

WriteString

  • signature: WriteString(s string) (int, error)

  • input: string to be written

  • output: number of bytes written

  • output (error): error message

WriteString writes the content of the provided string to the file.

Data Types

ConnectionStat: This is a data type defined in Go net package. It consists of network connection data. See here for more details.

type ConnectionStat struct {
	Fd     uint32  `json:"fd"`
	Family uint32  `json:"family"`
	Type   uint32  `json:"type"`
	Laddr  Addr    `json:"localaddr"`
	Raddr  Addr    `json:"remoteaddr"`
	Status string  `json:"status"`
	Uids   []int32 `json:"uids"`
	Pid    int32   `json:"pid"`
}

FileInfo: data type defined in Go fs pacakge. It consists of file information. See here for more details.

type FileInfo interface {
	Name() string       // base name of the file
	Size() int64        // length in bytes for regular files; system-dependent for others
	Mode() FileMode     // file mode bits
	ModTime() time.Time // modification time
	IsDir() bool        // abbreviation for Mode().IsDir()
	Sys() any           // underlying data source (can return nil)
}

Refer to cmd package for all other data types applicable.

Testing

The methods and interfaces in the backend subpacakge can be used to test the functionality of the cmd pacakge commands. Currently no unit test are defined since the implementaton is mostly wrappers around functions that should be tested somewhere else.

Proposed Functionality / Requirements

List of issues

All issues that are related to the design of cmd 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.

References

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