Rename engine to backend (#2950)

rename based on https://woodpecker-ci.org/docs/usage/terminiology

---------

Co-authored-by: 6543 <6543@obermui.de>

agent/runner.go

@@ -37,16 +37,16 @@ type Runner struct {
 	filter   rpc.Filter
 	hostname string
 	counter  *State
-	engine   *backend.Engine
+	backend  *backend.Backend
 }
 
-func NewRunner(workEngine rpc.Peer, f rpc.Filter, h string, state *State, backend *backend.Engine) Runner {
+func NewRunner(workEngine rpc.Peer, f rpc.Filter, h string, state *State, backend *backend.Backend) Runner {
 	return Runner{
 		client:   workEngine,
 		filter:   f,
 		hostname: h,
 		counter:  state,
-		engine:   backend,
+		backend:  backend,
 	}
 }
 
@@ -144,7 +144,7 @@ func (r *Runner) Run(runnerCtx context.Context) error {
 		pipeline.WithTaskUUID(fmt.Sprint(work.ID)),
 		pipeline.WithLogger(r.createLogger(logger, &uploads, work)),
 		pipeline.WithTracer(r.createTracer(ctxmeta, logger, work)),
-		pipeline.WithEngine(*r.engine),
+		pipeline.WithBackend(*r.backend),
 		pipeline.WithDescription(map[string]string{
 			"ID":       work.ID,
 			"Repo":     repoName,

cli/exec/exec.go

@@ -215,12 +215,12 @@ func execWithAxis(c *cli.Context, file, repoPath string, axis matrix.Axis) error
 	backendCtx := context.WithValue(c.Context, backendTypes.CliContext, c)
 	backend.Init(backendCtx)
 
-	engine, err := backend.FindEngine(backendCtx, c.String("backend-engine"))
+	backendEngine, err := backend.FindBackend(backendCtx, c.String("backend-engine"))
 	if err != nil {
 		return err
 	}
 
-	if _, err = engine.Load(backendCtx); err != nil {
+	if _, err = backendEngine.Load(backendCtx); err != nil {
 		return err
 	}
 
@@ -234,7 +234,7 @@ func execWithAxis(c *cli.Context, file, repoPath string, axis matrix.Axis) error
 		pipeline.WithContext(ctx),
 		pipeline.WithTracer(pipeline.DefaultTracer),
 		pipeline.WithLogger(defaultLogger),
-		pipeline.WithEngine(engine),
+		pipeline.WithBackend(backendEngine),
 		pipeline.WithDescription(map[string]string{
 			"CLI": "exec",
 		}),

cmd/agent/agent.go

@@ -156,22 +156,22 @@ func run(c *cli.Context) error {
 	parallel := c.Int("max-workflows")
 	wg.Add(parallel)
 
-	// new engine
-	engine, err := backend.FindEngine(backendCtx, c.String("backend-engine"))
+	// new backend
+	backendEngine, err := backend.FindBackend(backendCtx, c.String("backend-engine"))
 	if err != nil {
 		log.Error().Err(err).Msgf("cannot find backend engine '%s'", c.String("backend-engine"))
 		return err
 	}
 
-	// load engine (e.g. init api client)
-	engInfo, err := engine.Load(backendCtx)
+	// load backend (e.g. init api client)
+	engInfo, err := backendEngine.Load(backendCtx)
 	if err != nil {
 		log.Error().Err(err).Msg("cannot load backend engine")
 		return err
 	}
-	log.Debug().Msgf("loaded %s backend engine", engine.Name())
+	log.Debug().Msgf("loaded %s backend engine", backendEngine.Name())
 
-	agentConfig.AgentID, err = client.RegisterAgent(ctx, engInfo.Platform, engine.Name(), version.String(), parallel)
+	agentConfig.AgentID, err = client.RegisterAgent(ctx, engInfo.Platform, backendEngine.Name(), version.String(), parallel)
 	if err != nil {
 		return err
 	}
@@ -185,7 +185,7 @@ func run(c *cli.Context) error {
 	labels := map[string]string{
 		"hostname": hostname,
 		"platform": engInfo.Platform,
-		"backend":  engine.Name(),
+		"backend":  backendEngine.Name(),
 		"repo":     "*", // allow all repos by default
 	}
 
@@ -221,7 +221,7 @@ func run(c *cli.Context) error {
 		go func() {
 			defer wg.Done()
 
-			r := agent.NewRunner(client, filter, hostname, counter, &engine)
+			r := agent.NewRunner(client, filter, hostname, counter, &backendEngine)
 			log.Debug().Msgf("created new runner %d", i)
 
 			for {
@@ -241,7 +241,7 @@ func run(c *cli.Context) error {
 
 	log.Info().Msgf(
 		"Starting Woodpecker agent with version '%s' and backend '%s' using platform '%s' running up to %d pipelines in parallel",
-		version.String(), engine.Name(), engInfo.Platform, parallel)
+		version.String(), backendEngine.Name(), engInfo.Platform, parallel)
 
 	wg.Wait()
 	return nil

cmd/agent/flags.go

@@ -94,7 +94,7 @@ var flags = []cli.Flag{
 	&cli.StringFlag{
 		EnvVars: []string{"WOODPECKER_BACKEND"},
 		Name:    "backend-engine",
-		Usage:   "backend engine to run pipelines on",
+		Usage:   "backend to run pipelines on",
 		Value:   "auto-detect",
 	},
 }

pipeline/backend/backend.go

@@ -25,26 +25,26 @@ import (
 )
 
 var (
-	enginesByName map[string]types.Engine
-	engines       []types.Engine
+	backendsByName map[string]types.Backend
+	backends       []types.Backend
 )
 
 func Init(ctx context.Context) {
-	engines = []types.Engine{
+	backends = []types.Backend{
 		docker.New(),
 		local.New(),
 		kubernetes.New(ctx),
 	}
 
-	enginesByName = make(map[string]types.Engine)
-	for _, engine := range engines {
-		enginesByName[engine.Name()] = engine
+	backendsByName = make(map[string]types.Backend)
+	for _, engine := range backends {
+		backendsByName[engine.Name()] = engine
 	}
 }
 
-func FindEngine(ctx context.Context, engineName string) (types.Engine, error) {
-	if engineName == "auto-detect" {
-		for _, engine := range engines {
+func FindBackend(ctx context.Context, backendName string) (types.Backend, error) {
+	if backendName == "auto-detect" {
+		for _, engine := range backends {
 			if engine.IsAvailable(ctx) {
 				return engine, nil
 			}
@@ -53,9 +53,9 @@ func FindEngine(ctx context.Context, engineName string) (types.Engine, error) {
 		return nil, fmt.Errorf("can't detect an available backend engine")
 	}
 
-	engine, ok := enginesByName[engineName]
+	engine, ok := backendsByName[backendName]
 	if !ok {
-		return nil, fmt.Errorf("backend engine '%s' not found", engineName)
+		return nil, fmt.Errorf("backend engine '%s' not found", backendName)
 	}
 
 	return engine, nil

pipeline/backend/docker/docker.go

@@ -51,8 +51,8 @@ const (
 	volumeDriver        = "local"
 )
 
-// New returns a new Docker Engine.
-func New() backend.Engine {
+// New returns a new Docker Backend.
+func New() backend.Backend {
 	return &docker{
 		client: nil,
 	}
@@ -93,8 +93,8 @@ func httpClientOfOpts(dockerCertPath string, verifyTLS bool) *http.Client {
 	}
 }
 
-// Load new client for Docker Engine using environment variables.
-func (e *docker) Load(ctx context.Context) (*backend.EngineInfo, error) {
+// Load new client for Docker Backend using environment variables.
+func (e *docker) Load(ctx context.Context) (*backend.BackendInfo, error) {
 	c, ok := ctx.Value(backend.CliContext).(*cli.Context)
 	if !ok {
 		return nil, backend.ErrNoCliContextFound
@@ -142,7 +142,7 @@ func (e *docker) Load(ctx context.Context) (*backend.EngineInfo, error) {
 		e.volumes = append(e.volumes, strings.Join(parts, ":"))
 	}
 
-	return &backend.EngineInfo{
+	return &backend.BackendInfo{
 		Platform: e.info.OSType + "/" + normalizeArchType(e.info.Architecture),
 	}, nil
 }

pipeline/backend/kubernetes/kubernetes.go

@@ -24,9 +24,10 @@ import (
 	"time"
 
 	"github.com/rs/zerolog/log"
-	"go.woodpecker-ci.org/woodpecker/v2/pipeline/backend/types"
 	"gopkg.in/yaml.v3"
 
+	"go.woodpecker-ci.org/woodpecker/v2/pipeline/backend/types"
+
 	"github.com/urfave/cli/v2"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
@@ -101,8 +102,8 @@ func configFromCliContext(ctx context.Context) (*Config, error) {
 	return nil, types.ErrNoCliContextFound
 }
 
-// New returns a new Kubernetes Engine.
-func New(ctx context.Context) types.Engine {
+// New returns a new Kubernetes Backend.
+func New(ctx context.Context) types.Backend {
 	return &kube{
 		ctx: ctx,
 	}
@@ -117,7 +118,7 @@ func (e *kube) IsAvailable(context.Context) bool {
 	return len(host) > 0
 }
 
-func (e *kube) Load(context.Context) (*types.EngineInfo, error) {
+func (e *kube) Load(context.Context) (*types.BackendInfo, error) {
 	config, err := configFromCliContext(e.ctx)
 	if err != nil {
 		return nil, err
@@ -140,7 +141,7 @@ func (e *kube) Load(context.Context) (*types.EngineInfo, error) {
 
 	// TODO(2693): use info resp of kubeClient to define platform var
 	e.goos = runtime.GOOS
-	return &types.EngineInfo{
+	return &types.BackendInfo{
 		Platform: runtime.GOOS + "/" + runtime.GOARCH,
 	}, nil
 }

pipeline/backend/local/local.go

@@ -50,8 +50,8 @@ type local struct {
 	os, arch        string
 }
 
-// New returns a new local Engine.
-func New() types.Engine {
+// New returns a new local Backend.
+func New() types.Backend {
 	return &local{
 		os:   runtime.GOOS,
 		arch: runtime.GOARCH,
@@ -66,7 +66,7 @@ func (e *local) IsAvailable(context.Context) bool {
 	return true
 }
 
-func (e *local) Load(ctx context.Context) (*types.EngineInfo, error) {
+func (e *local) Load(ctx context.Context) (*types.BackendInfo, error) {
 	c, ok := ctx.Value(types.CliContext).(*cli.Context)
 	if ok {
 		e.tempDir = c.String("backend-local-temp-dir")
@@ -74,7 +74,7 @@ func (e *local) Load(ctx context.Context) (*types.EngineInfo, error) {
 
 	e.loadClone()
 
-	return &types.EngineInfo{
+	return &types.BackendInfo{
 		Platform: e.os + "/" + e.arch,
 	}, nil
 }

pipeline/backend/types/backend.go

@@ -14,6 +14,48 @@
 
 package types
 
+import (
+	"context"
+	"io"
+)
+
+// Backend defines a container orchestration backend and is used
+// to create and manage container resources.
+type Backend interface {
+	// Name returns the name of the backend.
+	Name() string
+
+	// IsAvailable check if the backend is available.
+	IsAvailable(ctx context.Context) bool
+
+	// Load loads the backend engine.
+	Load(ctx context.Context) (*BackendInfo, error)
+
+	// SetupWorkflow sets up the workflow environment.
+	SetupWorkflow(ctx context.Context, conf *Config, taskUUID string) error
+
+	// StartStep starts the workflow step.
+	StartStep(ctx context.Context, step *Step, taskUUID string) error
+
+	// WaitStep waits for the workflow step to complete and returns
+	// the completion results.
+	WaitStep(ctx context.Context, step *Step, taskUUID string) (*State, error)
+
+	// TailStep tails the workflow step logs.
+	TailStep(ctx context.Context, step *Step, taskUUID string) (io.ReadCloser, error)
+
+	// DestroyStep destroys the workflow step.
+	DestroyStep(ctx context.Context, step *Step, taskUUID string) error
+
+	// DestroyWorkflow destroys the workflow environment.
+	DestroyWorkflow(ctx context.Context, conf *Config, taskUUID string) error
+}
+
+// BackendInfo represents the reported information of a loaded backend
+type BackendInfo struct {
+	Platform string
+}
+
 // BackendOptions defines advanced options for specific backends
 type BackendOptions struct {
 	Kubernetes KubernetesBackendOptions `json:"kubernetes,omitempty"`

pipeline/backend/types/engine.go

@@ -1,57 +0,0 @@
-// Copyright 2023 Woodpecker Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package types
-
-import (
-	"context"
-	"io"
-)
-
-// Engine defines a container orchestration backend and is used
-// to create and manage container resources.
-type Engine interface {
-	// Name returns the name of the backend.
-	Name() string
-
-	// IsAvailable check if the backend is available.
-	IsAvailable(ctx context.Context) bool
-
-	// Load loads the backend engine.
-	Load(ctx context.Context) (*EngineInfo, error)
-
-	// SetupWorkflow sets up the workflow environment.
-	SetupWorkflow(ctx context.Context, conf *Config, taskUUID string) error
-
-	// StartStep starts the workflow step.
-	StartStep(ctx context.Context, step *Step, taskUUID string) error
-
-	// WaitStep waits for the workflow step to complete and returns
-	// the completion results.
-	WaitStep(ctx context.Context, step *Step, taskUUID string) (*State, error)
-
-	// TailStep tails the workflow step logs.
-	TailStep(ctx context.Context, step *Step, taskUUID string) (io.ReadCloser, error)
-
-	// DestroyStep destroys the workflow step.
-	DestroyStep(ctx context.Context, step *Step, taskUUID string) error
-
-	// DestroyWorkflow destroys the workflow environment.
-	DestroyWorkflow(ctx context.Context, conf *Config, taskUUID string) error
-}
-
-// EngineInfo represents the reported information of a loaded engine
-type EngineInfo struct {
-	Platform string
-}

pipeline/option.go

@@ -23,10 +23,10 @@ import (
 // Option configures a runtime option.
 type Option func(*Runtime)
 
-// WithEngine returns an option configured with a runtime engine.
-func WithEngine(engine backend.Engine) Option {
+// WithBackend returns an option configured with a runtime engine.
+func WithBackend(backend backend.Backend) Option {
 	return func(r *Runtime) {
-		r.engine = engine
+		r.engine = backend
 	}
 }
 

pipeline/pipeline.go

@@ -55,7 +55,7 @@ type (
 type Runtime struct {
 	err     error
 	spec    *backend.Config
-	engine  backend.Engine
+	engine  backend.Backend
 	started int64
 
 	ctx    context.Context