hooks

README

edgex-snap-hooks

Snap hooks library used by EdgeX Foundry Go service snaps.
It provides utilites to implement snap hooks, including some wrappers for the snapctl commands.

Usage

Download or upgrade to the latest version:

go get github.com/canonical/edgex-snap-hooks/v3

Please refer to go get docs for details.

The jakarta branch is split from master as of v2.1.3. It would only receive patch updates but no minor or major releases. The jakarta-only tags follow v2.1.X+jakarta scheme, where X is greater than 3.

Example

package main

import (
	"fmt"
	"os"

	hooks "github.com/canonical/edgex-snap-hooks/v3"
)

func main() {
	var err error

	if err = hooks.Init(false, "edgex-device-example"); err != nil {
		fmt.Printf("initialization failure: %s", err)
		os.Exit(1)
	}

	// copy file from $SNAP to $SNAP_DATA
	if err = hooks.CopyFile(hooks.Snap+"/config.json", hooks.SnapData+"config.json"); err != nil {
		hooks.Error(err.Error())
		os.Exit(1)
	}
  
	// read env var override configuration
	cli := hooks.NewSnapCtl()
	envJSON, err := cli.Config(hooks.EnvConfig)
	if err != nil {
		hooks.Error(fmt.Sprintf("Reading config 'env' failed: %v", err))
		os.Exit(1)
	}
	hooks.Debug(fmt.Sprintf("envJSON: %s", envJSON))
}

Testing

The tests need to run in a snap environment:

Build and install:

snapcraft
sudo snap install --dangerous ./edgex-snap-hooks_test_amd64.snap

The tests files are read relative to project source inside the snap. The edgex-snap-hooks.test command runs go test -v --cover internally and accepts all other go test arguments.

Run all tests:

make test

Run top-level tests:

sudo edgex-snap-hooks.test

Run tests in one package, e.g. snapctl:

sudo edgex-snap-hooks.test ./snapctl

Run one unit test, e.g. TestGet:

sudo edgex-snap-hooks.test ./snapctl -run TestGet

Development

make try

You can now edit the files locally, copy them to prime directory, and re-run the tests without rebuilding the project. E.g.:

make sync
sudo edgex-snap-hooks.test ./snapctl

Documentation

Index

• func CopyDir(srcPath string, dstPath string) error
• func CopyFile(srcPath, destPath string) error
• func CopyFileReplace(srcPath, destPath string, rStrings map[string]string) error

Functions

func CopyDir

func CopyDir(srcPath string, dstPath string) error

CopyDir copies a whole directory recursively snippet from https://blog.depa.do/post/copy-files-and-directories-in-go

func CopyFile

func CopyFile(srcPath, destPath string) error

CopyFile copies a file within the snap

func CopyFileReplace

func CopyFileReplace(srcPath, destPath string, rStrings map[string]string) error

CopyFileReplace copies a file within the snap and replaces strings using the string/replace values in the rStrings parameter.