Sync gitea app path for git hooks and authorized keys when starting (#17335)

Gitea writes its own AppPath into git hook scripts. If Gitea's AppPath changes, then the git push will fail.

This PR:

* Introduce an AppState module, it can persist app states into database
* During GlobalInit, Gitea will check if the current AppPath is the same as last one. If they don't match, Gitea will sync git hooks.
* Refactor some code to make them more clear.
* Also, "Detect if gitea binary's name changed" #11341 is related, we call models.RewriteAllPublicKeys to update ssh authorized_keys file

4 files changed, 141 insertions, 0 deletions

diff --git a/modules/appstate/appstate.go b/modules/appstate/appstate.go
new file mode 100644
index 0000000000..f65f5367e2
--- /dev/null
+++ b/modules/appstate/appstate.go
@@ -0,0 +1,25 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package appstate
+
+// StateStore is the interface to get/set app state items
+type StateStore interface {
+	Get(item StateItem) error
+	Set(item StateItem) error
+}
+
+// StateItem provides the name for a state item. the name will be used to generate filenames, etc
+type StateItem interface {
+	Name() string
+}
+
+// AppState contains the state items for the app
+var AppState StateStore
+
+// Init initialize AppState interface
+func Init() error {
+	AppState = &DBStore{}
+	return nil
+}
diff --git a/modules/appstate/appstate_test.go b/modules/appstate/appstate_test.go
new file mode 100644
index 0000000000..d8ab0a45fd
--- /dev/null
+++ b/modules/appstate/appstate_test.go
@@ -0,0 +1,64 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package appstate
+
+import (
+	"path/filepath"
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMain(m *testing.M) {
+	db.MainTest(m, filepath.Join("..", ".."), "")
+}
+
+type testItem1 struct {
+	Val1 string
+	Val2 int
+}
+
+func (*testItem1) Name() string {
+	return "test-item1"
+}
+
+type testItem2 struct {
+	K string
+}
+
+func (*testItem2) Name() string {
+	return "test-item2"
+}
+
+func TestAppStateDB(t *testing.T) {
+	assert.NoError(t, db.PrepareTestDatabase())
+
+	as := &DBStore{}
+
+	item1 := new(testItem1)
+	assert.NoError(t, as.Get(item1))
+	assert.Equal(t, "", item1.Val1)
+	assert.EqualValues(t, 0, item1.Val2)
+
+	item1 = new(testItem1)
+	item1.Val1 = "a"
+	item1.Val2 = 2
+	assert.NoError(t, as.Set(item1))
+
+	item2 := new(testItem2)
+	item2.K = "V"
+	assert.NoError(t, as.Set(item2))
+
+	item1 = new(testItem1)
+	assert.NoError(t, as.Get(item1))
+	assert.Equal(t, "a", item1.Val1)
+	assert.EqualValues(t, 2, item1.Val2)
+
+	item2 = new(testItem2)
+	assert.NoError(t, as.Get(item2))
+	assert.Equal(t, "V", item2.K)
+}
diff --git a/modules/appstate/db.go b/modules/appstate/db.go
new file mode 100644
index 0000000000..a594b01d85
--- /dev/null
+++ b/modules/appstate/db.go
@@ -0,0 +1,37 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package appstate
+
+import (
+	"code.gitea.io/gitea/models/appstate"
+	"code.gitea.io/gitea/modules/json"
+
+	"github.com/yuin/goldmark/util"
+)
+
+// DBStore can be used to store app state items in local filesystem
+type DBStore struct {
+}
+
+// Get reads the state item
+func (f *DBStore) Get(item StateItem) error {
+	content, err := appstate.GetAppStateContent(item.Name())
+	if err != nil {
+		return err
+	}
+	if content == "" {
+		return nil
+	}
+	return json.Unmarshal(util.StringToReadOnlyBytes(content), item)
+}
+
+// Set saves the state item
+func (f *DBStore) Set(item StateItem) error {
+	b, err := json.Marshal(item)
+	if err != nil {
+		return err
+	}
+	return appstate.SaveAppStateContent(item.Name(), util.BytesToReadOnlyString(b))
+}
diff --git a/modules/appstate/item_runtime.go b/modules/appstate/item_runtime.go
new file mode 100644
index 0000000000..7fdc53f642
--- /dev/null
+++ b/modules/appstate/item_runtime.go
@@ -0,0 +1,15 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package appstate
+
+// RuntimeState contains app state for runtime, and we can save remote version for update checker here in future
+type RuntimeState struct {
+	LastAppPath string `json:"last_app_path"`
+}
+
+// Name returns the item name
+func (a RuntimeState) Name() string {
+	return "runtime-state"
+}