load plugins in order of dependencies.

build

@@ -44,6 +44,8 @@ fi
 for plugPath in ./plugins/*; do
     pushd $plugPath
 
+    echo "Building plugin: $plugPath"
+
     # build plugin
     go build -modfile=go.plug.mod -buildmode=plugin -o "../../bin/plugins/${plugPath##*/}.so"
 

go.mod

@@ -16,9 +16,11 @@ require (
 	github.com/rs/zerolog v1.26.1
 	github.com/spf13/cobra v1.4.0
 	github.com/spf13/viper v1.10.1
+	github.com/stretchr/testify v1.7.1
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fsnotify/fsnotify v1.5.1 // indirect
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
@@ -39,6 +41,7 @@ require (
 	github.com/pion/transport v0.13.0 // indirect
 	github.com/pion/turn/v2 v2.0.8 // indirect
 	github.com/pion/udp v0.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/afero v1.8.0 // indirect
 	github.com/spf13/cast v1.4.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
@@ -51,4 +54,5 @@ require (
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

go.sum

@@ -580,6 +580,7 @@ gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
+gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

internal/plugins/dependency.go

@@ -0,0 +1,130 @@
+package plugins
+
+import (
+	"fmt"
+
+	"github.com/rs/zerolog"
+
+	"gitlab.com/demodesk/neko/server/pkg/types"
+)
+
+type dependency struct {
+	plugin    types.Plugin
+	dependsOn []*dependency
+	invoked   bool
+	logger    zerolog.Logger
+}
+
+type dependiencies struct {
+	deps   map[string]*dependency
+	logger zerolog.Logger
+}
+
+func (d *dependiencies) addPlugin(plugin types.Plugin) error {
+	plug, ok := d.deps[plugin.Name()]
+	if !ok {
+		plug = &dependency{}
+	} else if plug.plugin != nil {
+		return fmt.Errorf("plugin '%s' already added", plugin.Name())
+	}
+
+	plug.plugin = plugin
+	plug.logger = d.logger
+	d.deps[plugin.Name()] = plug
+
+	dplug, ok := plugin.(types.DependablePlugin)
+	if !ok {
+		return nil
+	}
+
+	for _, dep := range dplug.DependsOn() {
+		var dependsOn *dependency
+		dependsOn, ok = d.deps[dep]
+		if !ok {
+			dependsOn = &dependency{}
+		} else if dependsOn.plugin != nil {
+			// if there is a cyclical dependency, break it and return error
+			if tdep := dependsOn.findPlugin(plugin.Name()); tdep != nil {
+				dependsOn.dependsOn = nil
+				delete(d.deps, plugin.Name())
+				return fmt.Errorf("cyclical dependency detected: '%s' <-> '%s'", plugin.Name(), tdep.plugin.Name())
+			}
+		}
+
+		plug.dependsOn = append(plug.dependsOn, dependsOn)
+		d.deps[dep] = dependsOn
+	}
+
+	return nil
+}
+
+func (d *dependiencies) start(pm types.PluginManagers) error {
+	for _, p := range d.deps {
+		if err := p.start(pm); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (d *dependiencies) findPlugin(name string) (*dependency, bool) {
+	for _, p := range d.deps {
+		if found := p.findPlugin(name); found != nil {
+			return found, true
+		}
+	}
+	return nil, false
+}
+
+func (a *dependency) findPlugin(name string) *dependency {
+	if a == nil {
+		return nil
+	}
+
+	if a.plugin.Name() == name {
+		return a
+	}
+
+	for _, p := range a.dependsOn {
+		if found := p.findPlugin(name); found != nil {
+			return found
+		}
+	}
+
+	return nil
+}
+
+func (d *dependiencies) forEach(f func(*dependency) error) error {
+	for _, dp := range d.deps {
+		if err := f(dp); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (d *dependiencies) len() int {
+	return len(d.deps)
+}
+
+func (a *dependency) start(pm types.PluginManagers) error {
+	if a.invoked {
+		return nil
+	}
+
+	a.invoked = true
+
+	for _, do := range a.dependsOn {
+		if err := do.start(pm); err != nil {
+			return err
+		}
+	}
+
+	err := a.plugin.Start(pm)
+	a.logger.Err(err).Str("plugin", a.plugin.Name()).Msg("plugin start")
+	if err != nil {
+		return fmt.Errorf("plugin %s failed to start: %s", a.plugin.Name(), err)
+	}
+
+	return nil
+}

internal/plugins/dependency_test.go

@@ -0,0 +1,629 @@
+package plugins
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"gitlab.com/demodesk/neko/server/pkg/types"
+)
+
+func Test_deps_addPlugin(t *testing.T) {
+	type args struct {
+		p []types.Plugin
+	}
+	tests := []struct {
+		name     string
+		args     args
+		want     map[string]*dependency
+		skipRun  bool
+		wantErr1 bool
+		wantErr2 bool
+	}{
+		{
+			name: "three plugins - no dependencies",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "first"},
+					&dummyPlugin{name: "second"},
+					&dummyPlugin{name: "third"},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"second": {
+					plugin:    &dummyPlugin{name: "second", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"third": {
+					plugin:    &dummyPlugin{name: "third", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+			},
+		}, {
+			name: "three plugins - one dependency",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "third", dep: []string{"second"}},
+					&dummyPlugin{name: "first"},
+					&dummyPlugin{name: "second"},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"second": {
+					plugin:    &dummyPlugin{name: "second", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"second"}, idx: 1},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "second", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+					},
+				},
+			},
+		}, {
+			name: "three plugins - one double dependency",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "third", dep: []string{"first", "second"}},
+					&dummyPlugin{name: "first"},
+					&dummyPlugin{name: "second"},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"second": {
+					plugin:    &dummyPlugin{name: "second", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"first", "second"}, idx: 1},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+						{
+							plugin:    &dummyPlugin{name: "second", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+					},
+				},
+			},
+		}, {
+			name: "three plugins - two dependencies",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "third", dep: []string{"first"}},
+					&dummyPlugin{name: "first"},
+					&dummyPlugin{name: "second", dep: []string{"first"}},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first"},
+					invoked:   false,
+					dependsOn: nil,
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"first"}},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first"},
+							invoked:   false,
+							dependsOn: nil,
+						},
+					},
+				},
+				"second": {
+					plugin:  &dummyPlugin{name: "second", dep: []string{"first"}},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first"},
+							invoked:   false,
+							dependsOn: nil,
+						},
+					},
+				},
+			},
+			skipRun: true,
+		}, {
+			name: "three plugins - three dependencies",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "third", dep: []string{"second"}},
+					&dummyPlugin{name: "first"},
+					&dummyPlugin{name: "second", dep: []string{"first"}},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"second": {
+					plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 1},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+					},
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"second"}, idx: 2},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 1},
+							invoked: true,
+							dependsOn: []*dependency{
+								{
+									plugin:    &dummyPlugin{name: "first", idx: 0},
+									invoked:   true,
+									dependsOn: nil,
+								},
+							},
+						},
+					},
+				},
+			},
+		}, {
+			name: "four plugins - added in reverse order, with dependencies",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "forth", dep: []string{"third"}},
+					&dummyPlugin{name: "third", dep: []string{"second"}},
+					&dummyPlugin{name: "second", dep: []string{"first"}},
+					&dummyPlugin{name: "first"},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first", idx: 0},
+					invoked:   false,
+					dependsOn: nil,
+				},
+				"second": {
+					plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 0},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first", idx: 0},
+							invoked:   false,
+							dependsOn: nil,
+						},
+					},
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"second"}, idx: 0},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 0},
+							invoked: false,
+							dependsOn: []*dependency{
+								{
+									plugin:    &dummyPlugin{name: "first", idx: 0},
+									invoked:   false,
+									dependsOn: nil,
+								},
+							},
+						},
+					},
+				},
+				"forth": {
+					plugin:  &dummyPlugin{name: "forth", dep: []string{"third"}, idx: 0},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "third", dep: []string{"second"}, idx: 0},
+							invoked: false,
+							dependsOn: []*dependency{
+								{
+									plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 0},
+									invoked: false,
+									dependsOn: []*dependency{
+										{
+											plugin:    &dummyPlugin{name: "first", idx: 0},
+											invoked:   false,
+											dependsOn: nil,
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+			skipRun: true,
+		}, {
+			name: "four plugins - two double dependencies",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "forth", dep: []string{"first", "third"}},
+					&dummyPlugin{name: "third", dep: []string{"first", "second"}},
+					&dummyPlugin{name: "second"},
+					&dummyPlugin{name: "first"},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:    &dummyPlugin{name: "first", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"second": {
+					plugin:    &dummyPlugin{name: "second", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"first", "second"}, idx: 1},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+						{
+							plugin:    &dummyPlugin{name: "second", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+					},
+				},
+				"forth": {
+					plugin:  &dummyPlugin{name: "forth", dep: []string{"first", "third"}, idx: 2},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+						{
+							plugin:  &dummyPlugin{name: "third", dep: []string{"first", "second"}, idx: 1},
+							invoked: true,
+							dependsOn: []*dependency{
+								{
+									plugin:    &dummyPlugin{name: "first", idx: 0},
+									invoked:   true,
+									dependsOn: nil,
+								},
+								{
+									plugin:    &dummyPlugin{name: "second", idx: 0},
+									invoked:   true,
+									dependsOn: nil,
+								},
+							},
+						},
+					},
+				},
+			},
+		}, {
+			// So, when we have plugin A in the list and want to add plugin C we can't determine the proper order without
+			// resolving their direct dependiencies first:
+			//
+			// Can be C->D->A->B if D depends on A
+			//
+			// So to do it properly I would imagine tht we need to resolve all direct dependiencies first and build multiple lists:
+			//
+			// i.e. A->B->C D F->G
+			//
+			// and then join these lists in any order.
+			name: "add indirect dependency CDAB",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "A", dep: []string{"B"}},
+					&dummyPlugin{name: "C", dep: []string{"D"}},
+					&dummyPlugin{name: "B"},
+					&dummyPlugin{name: "D", dep: []string{"A"}},
+				},
+			},
+			want: map[string]*dependency{
+				"B": {
+					plugin:    &dummyPlugin{name: "B", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"A": {
+					plugin:  &dummyPlugin{name: "A", dep: []string{"B"}, idx: 1},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "B", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+					},
+				},
+				"D": {
+					plugin:  &dummyPlugin{name: "D", dep: []string{"A"}, idx: 2},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "A", dep: []string{"B"}, idx: 1},
+							invoked: true,
+							dependsOn: []*dependency{
+								{
+									plugin:    &dummyPlugin{name: "B", idx: 0},
+									invoked:   true,
+									dependsOn: nil,
+								},
+							},
+						},
+					},
+				},
+				"C": {
+					plugin:  &dummyPlugin{name: "C", dep: []string{"D"}, idx: 3},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "D", dep: []string{"A"}, idx: 2},
+							invoked: true,
+							dependsOn: []*dependency{
+								{
+									plugin:  &dummyPlugin{name: "A", dep: []string{"B"}, idx: 1},
+									invoked: true,
+									dependsOn: []*dependency{
+										{
+											plugin:    &dummyPlugin{name: "B", idx: 0},
+											invoked:   true,
+											dependsOn: nil,
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		}, {
+			// So, when we have plugin A in the list and want to add plugin C we can't determine the proper order without
+			// resolving their direct dependiencies first:
+			//
+			// Can be A->B->C->D (in this test) if B depends on C
+			//
+			// So to do it properly I would imagine tht we need to resolve all direct dependiencies first and build multiple lists:
+			//
+			// i.e. A->B->C D F->G
+			//
+			// and then join these lists in any order.
+			name: "add indirect dependency ABCD",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "C", dep: []string{"D"}},
+					&dummyPlugin{name: "D"},
+					&dummyPlugin{name: "B", dep: []string{"C"}},
+					&dummyPlugin{name: "A", dep: []string{"B"}},
+				},
+			},
+			want: map[string]*dependency{
+				"D": {
+					plugin:    &dummyPlugin{name: "D", idx: 0},
+					invoked:   true,
+					dependsOn: nil,
+				},
+				"C": {
+					plugin:  &dummyPlugin{name: "C", dep: []string{"D"}, idx: 1},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "D", idx: 0},
+							invoked:   true,
+							dependsOn: nil,
+						},
+					},
+				},
+				"B": {
+					plugin:  &dummyPlugin{name: "B", dep: []string{"C"}, idx: 2},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "C", dep: []string{"D"}, idx: 1},
+							invoked: true,
+							dependsOn: []*dependency{
+								{
+									plugin:    &dummyPlugin{name: "D", idx: 0},
+									invoked:   true,
+									dependsOn: nil,
+								},
+							},
+						},
+					},
+				},
+				"A": {
+					plugin:  &dummyPlugin{name: "A", dep: []string{"B"}, idx: 3},
+					invoked: true,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "B", dep: []string{"C"}, idx: 2},
+							invoked: true,
+							dependsOn: []*dependency{
+								{
+									plugin:  &dummyPlugin{name: "C", dep: []string{"D"}, idx: 1},
+									invoked: true,
+									dependsOn: []*dependency{
+										{
+											plugin:    &dummyPlugin{name: "D", idx: 0},
+											invoked:   true,
+											dependsOn: nil,
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		}, {
+			name: "add duplicate plugin",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "first"},
+					&dummyPlugin{name: "first"},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {plugin: &dummyPlugin{name: "first", idx: 0}, invoked: true},
+			},
+			wantErr1: true,
+		}, {
+			name: "cyclical dependency",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "first", dep: []string{"second"}},
+					&dummyPlugin{name: "second", dep: []string{"first"}},
+				},
+			},
+			want: map[string]*dependency{
+				"first": {
+					plugin:  &dummyPlugin{name: "first", dep: []string{"second"}, idx: 1},
+					invoked: true,
+				},
+			},
+			wantErr1: true,
+		}, {
+			name: "four plugins - cyclical transitive dependencies in reverse order",
+			args: args{
+				p: []types.Plugin{
+					&dummyPlugin{name: "forth", dep: []string{"third"}},
+					&dummyPlugin{name: "third", dep: []string{"second"}},
+					&dummyPlugin{name: "second", dep: []string{"first"}},
+					&dummyPlugin{name: "first", dep: []string{"forth"}},
+				},
+			},
+			want: map[string]*dependency{
+				"second": {
+					plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 0},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:    &dummyPlugin{name: "first", dep: []string{"forth"}, idx: 0},
+							invoked:   false,
+							dependsOn: nil,
+						},
+					},
+				},
+				"third": {
+					plugin:  &dummyPlugin{name: "third", dep: []string{"second"}, idx: 0},
+					invoked: false,
+					dependsOn: []*dependency{
+						{
+							plugin:  &dummyPlugin{name: "second", dep: []string{"first"}, idx: 0},
+							invoked: false,
+							dependsOn: []*dependency{
+								{
+									plugin:    &dummyPlugin{name: "first", dep: []string{"forth"}, idx: 0},
+									invoked:   false,
+									dependsOn: nil,
+								},
+							},
+						},
+					},
+				},
+				"forth": {
+					plugin:    &dummyPlugin{name: "forth", dep: []string{"third"}, idx: 0},
+					invoked:   false,
+					dependsOn: nil,
+				},
+			},
+			wantErr1: true,
+			skipRun:  true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			d := &dependiencies{deps: make(map[string]*dependency)}
+
+			var (
+				err     error
+				counter int
+			)
+			for _, p := range tt.args.p {
+				if !tt.skipRun {
+					p.(*dummyPlugin).counter = &counter
+				}
+				if err = d.addPlugin(p); err != nil {
+					break
+				}
+			}
+			if err != nil != tt.wantErr1 {
+				t.Errorf("dependiencies.addPlugin() error = %v, wantErr1 %v", err, tt.wantErr1)
+				return
+			}
+
+			if !tt.skipRun {
+				if err := d.start(types.PluginManagers{}); (err != nil) != tt.wantErr2 {
+					t.Errorf("dependiencies.start() error = %v, wantErr1 %v", err, tt.wantErr2)
+				}
+			}
+
+			assert.Equal(t, tt.want, d.deps)
+		})
+	}
+}
+
+type dummyPlugin struct {
+	name    string
+	dep     []string
+	idx     int
+	counter *int
+}
+
+func (d dummyPlugin) Name() string {
+	return d.name
+}
+
+func (d dummyPlugin) DependsOn() []string {
+	return d.dep
+}
+
+func (d dummyPlugin) Config() types.PluginConfig {
+	return nil
+}
+
+func (d *dummyPlugin) Start(types.PluginManagers) error {
+	if len(d.dep) > 0 {
+		*d.counter++
+		d.idx = *d.counter
+	}
+	d.counter = nil
+	return nil
+}
+
+func (d dummyPlugin) Shutdown() error {
+	return nil
+}

internal/plugins/manager.go

@@ -16,18 +16,22 @@ import (
 
 type ManagerCtx struct {
 	logger  zerolog.Logger
-	plugins map[string]types.Plugin
+	plugins dependiencies
 }
 
 func New(config *config.Plugins) *ManagerCtx {
 	manager := &ManagerCtx{
-		logger:  log.With().Str("module", "plugins").Logger(),
+		logger: log.With().Str("module", "plugins").Logger(),
-		plugins: map[string]types.Plugin{},
+		plugins: dependiencies{
+			deps: make(map[string]*dependency),
+		},
 	}
 
+	manager.plugins.logger = manager.logger
+
 	if config.Enabled {
 		err := manager.loadDir(config.Dir)
-		manager.logger.Err(err).Msgf("loading finished, total %d plugins", len(manager.plugins))
+		manager.logger.Err(err).Msgf("loading finished, total %d plugins", manager.plugins.len())
 	}
 
 	return manager
@@ -45,7 +49,6 @@ func (manager *ManagerCtx) loadDir(dir string) error {
 
 		err = manager.load(path)
 		manager.logger.Err(err).Str("plugin", path).Msg("loading a plugin")
-
 		return nil
 	})
 }
@@ -66,27 +69,28 @@ func (manager *ManagerCtx) load(path string) error {
 		return fmt.Errorf("not a valid plugin")
 	}
 
-	_, ok = manager.plugins[p.Name()]
+	if err = manager.plugins.addPlugin(p); err != nil {
-	if ok {
+		return fmt.Errorf("failed to add plugin '%s': %w", p.Name(), err)
-		return fmt.Errorf("plugin '%s' already exists", p.Name())
 	}
 
-	manager.plugins[p.Name()] = p
+	manager.logger.Info().Msgf("loaded plugin '%s', total %d plugins", p.Name(), manager.plugins.len())
 	return nil
 }
 
 func (manager *ManagerCtx) InitConfigs(cmd *cobra.Command) {
-	for path, plug := range manager.plugins {
+	_ = manager.plugins.forEach(func(plug *dependency) error {
-		if err := plug.Config().Init(cmd); err != nil {
+		if err := plug.plugin.Config().Init(cmd); err != nil {
-			log.Err(err).Str("plugin", path).Msg("unable to initialize configuration")
+			log.Err(err).Str("plugin", plug.plugin.Name()).Msg("unable to initialize configuration")
 		}
-	}
+		return nil
+	})
 }
 
 func (manager *ManagerCtx) SetConfigs() {
-	for _, plug := range manager.plugins {
+	_ = manager.plugins.forEach(func(plug *dependency) error {
-		plug.Config().Set()
+		plug.plugin.Config().Set()
-	}
+		return nil
+	})
 }
 
 func (manager *ManagerCtx) Start(
@@ -94,34 +98,30 @@ func (manager *ManagerCtx) Start(
 	webSocketManager types.WebSocketManager,
 	apiManager types.ApiManager,
 ) {
-	for path, plug := range manager.plugins {
+	_ = manager.plugins.start(types.PluginManagers{
-		err := plug.Start(types.PluginManagers{
+		SessionManager:        sessionManager,
-			SessionManager:        sessionManager,
+		WebSocketManager:      webSocketManager,
-			WebSocketManager:      webSocketManager,
+		ApiManager:            apiManager,
-			ApiManager:            apiManager,
+		LoadServiceFromPlugin: manager.LookupService,
-			LoadServiceFromPlugin: manager.LookupService,
+	})
-		})
-
-		manager.logger.Err(err).Str("plugin", path).Msg("plugin start")
-	}
 }
 
 func (manager *ManagerCtx) Shutdown() error {
-	for path, plug := range manager.plugins {
+	_ = manager.plugins.forEach(func(plug *dependency) error {
-		err := plug.Shutdown()
+		err := plug.plugin.Shutdown()
-		manager.logger.Err(err).Str("plugin", path).Msg("plugin shutdown")
+		manager.logger.Err(err).Str("plugin", plug.plugin.Name()).Msg("plugin shutdown")
-	}
+		return nil
-
+	})
 	return nil
 }
 
 func (manager *ManagerCtx) LookupService(pluginName string) (any, error) {
-	plug, ok := manager.plugins[pluginName]
+	plug, ok := manager.plugins.findPlugin(pluginName)
 	if !ok {
 		return nil, fmt.Errorf("plugin '%s' not found", pluginName)
 	}
 
-	expPlug, ok := plug.(types.ExposablePlugin)
+	expPlug, ok := plug.plugin.(types.ExposablePlugin)
 	if !ok {
 		return nil, fmt.Errorf("plugin '%s' is not exposable", pluginName)
 	}

pkg/types/plugins.go

@@ -13,6 +13,11 @@ type Plugin interface {
 	Shutdown() error
 }
 
+type DependablePlugin interface {
+	Plugin
+	DependsOn() []string
+}
+
 type ExposablePlugin interface {
 	Plugin
 	ExposeService() any