bridge.go

  1// Package core contains the target-agnostic code to define and run a bridge
  2package core
  3
  4import (
  5	"fmt"
  6	"reflect"
  7	"regexp"
  8	"sort"
  9	"strings"
 10	"time"
 11
 12	"github.com/MichaelMure/git-bug/cache"
 13	"github.com/MichaelMure/git-bug/repository"
 14	"github.com/pkg/errors"
 15)
 16
 17var ErrImportNotSupported = errors.New("import is not supported")
 18var ErrExportNotSupported = errors.New("export is not supported")
 19
 20const bridgeConfigKeyPrefix = "git-bug.bridge"
 21
 22var bridgeImpl map[string]reflect.Type
 23
 24// Bridge is a wrapper around a BridgeImpl that will bind low-level
 25// implementation with utility code to provide high-level functions.
 26type Bridge struct {
 27	Name     string
 28	repo     *cache.RepoCache
 29	impl     BridgeImpl
 30	importer Importer
 31	exporter Exporter
 32	conf     Configuration
 33	initDone bool
 34}
 35
 36// Register will register a new BridgeImpl
 37func Register(impl BridgeImpl) {
 38	if bridgeImpl == nil {
 39		bridgeImpl = make(map[string]reflect.Type)
 40	}
 41	bridgeImpl[impl.Target()] = reflect.TypeOf(impl)
 42}
 43
 44// Targets return all known bridge implementation target
 45func Targets() []string {
 46	var result []string
 47
 48	for key := range bridgeImpl {
 49		result = append(result, key)
 50	}
 51
 52	sort.Strings(result)
 53
 54	return result
 55}
 56
 57// Instantiate a new Bridge for a repo, from the given target and name
 58func NewBridge(repo *cache.RepoCache, target string, name string) (*Bridge, error) {
 59	implType, ok := bridgeImpl[target]
 60	if !ok {
 61		return nil, fmt.Errorf("unknown bridge target %v", target)
 62	}
 63
 64	impl := reflect.New(implType).Elem().Interface().(BridgeImpl)
 65
 66	bridge := &Bridge{
 67		Name: name,
 68		repo: repo,
 69		impl: impl,
 70	}
 71
 72	return bridge, nil
 73}
 74
 75// Instantiate a new bridge for a repo, from the combined target and name contained
 76// in the full name
 77func NewBridgeFromFullName(repo *cache.RepoCache, fullName string) (*Bridge, error) {
 78	target, name, err := splitFullName(fullName)
 79	if err != nil {
 80		return nil, err
 81	}
 82
 83	return NewBridge(repo, target, name)
 84}
 85
 86// Attempt to retrieve a default bridge for the given repo. If zero or multiple
 87// bridge exist, it fails.
 88func DefaultBridge(repo *cache.RepoCache) (*Bridge, error) {
 89	bridges, err := ConfiguredBridges(repo)
 90	if err != nil {
 91		return nil, err
 92	}
 93
 94	if len(bridges) == 0 {
 95		return nil, fmt.Errorf("no configured bridge")
 96	}
 97
 98	if len(bridges) > 1 {
 99		return nil, fmt.Errorf("multiple bridge are configured, you need to select one explicitely")
100	}
101
102	target, name, err := splitFullName(bridges[0])
103	if err != nil {
104		return nil, err
105	}
106
107	return NewBridge(repo, target, name)
108}
109
110func splitFullName(fullName string) (string, string, error) {
111	split := strings.Split(fullName, ".")
112
113	if len(split) != 2 {
114		return "", "", fmt.Errorf("bad bridge fullname: %s", fullName)
115	}
116
117	return split[0], split[1], nil
118}
119
120// ConfiguredBridges return the list of bridge that are configured for the given
121// repo
122func ConfiguredBridges(repo repository.RepoCommon) ([]string, error) {
123	configs, err := repo.ReadConfigs(bridgeConfigKeyPrefix + ".")
124	if err != nil {
125		return nil, errors.Wrap(err, "can't read configured bridges")
126	}
127
128	re, err := regexp.Compile(bridgeConfigKeyPrefix + `.([^.]+\.[^.]+)`)
129	if err != nil {
130		panic(err)
131	}
132
133	set := make(map[string]interface{})
134
135	for key := range configs {
136		res := re.FindStringSubmatch(key)
137
138		if res == nil {
139			continue
140		}
141
142		set[res[1]] = nil
143	}
144
145	result := make([]string, len(set))
146
147	i := 0
148	for key := range set {
149		result[i] = key
150		i++
151	}
152
153	return result, nil
154}
155
156// Remove a configured bridge
157func RemoveBridge(repo repository.RepoCommon, fullName string) error {
158	re, err := regexp.Compile(`^[^.]+\.[^.]+$`)
159	if err != nil {
160		panic(err)
161	}
162
163	if !re.MatchString(fullName) {
164		return fmt.Errorf("bad bridge fullname: %s", fullName)
165	}
166
167	keyPrefix := fmt.Sprintf("git-bug.bridge.%s", fullName)
168	return repo.RmConfigs(keyPrefix)
169}
170
171// Configure run the target specific configuration process
172func (b *Bridge) Configure() error {
173	conf, err := b.impl.Configure(b.repo)
174	if err != nil {
175		return err
176	}
177
178	b.conf = conf
179
180	return b.storeConfig(conf)
181}
182
183func (b *Bridge) storeConfig(conf Configuration) error {
184	for key, val := range conf {
185		storeKey := fmt.Sprintf("git-bug.bridge.%s.%s.%s", b.impl.Target(), b.Name, key)
186
187		err := b.repo.StoreConfig(storeKey, val)
188		if err != nil {
189			return errors.Wrap(err, "error while storing bridge configuration")
190		}
191	}
192
193	return nil
194}
195
196func (b *Bridge) ensureConfig() error {
197	if b.conf == nil {
198		conf, err := b.loadConfig()
199		if err != nil {
200			return err
201		}
202		b.conf = conf
203	}
204
205	return nil
206}
207
208func (b *Bridge) loadConfig() (Configuration, error) {
209	keyPrefix := fmt.Sprintf("git-bug.bridge.%s.%s.", b.impl.Target(), b.Name)
210
211	pairs, err := b.repo.ReadConfigs(keyPrefix)
212	if err != nil {
213		return nil, errors.Wrap(err, "error while reading bridge configuration")
214	}
215
216	result := make(Configuration, len(pairs))
217	for key, value := range pairs {
218		key := strings.TrimPrefix(key, keyPrefix)
219		result[key] = value
220	}
221
222	err = b.impl.ValidateConfig(result)
223	if err != nil {
224		return nil, errors.Wrap(err, "invalid configuration")
225	}
226
227	return result, nil
228}
229
230func (b *Bridge) getImporter() Importer {
231	if b.importer == nil {
232		b.importer = b.impl.NewImporter()
233	}
234
235	return b.importer
236}
237
238func (b *Bridge) getExporter() Exporter {
239	if b.exporter == nil {
240		b.exporter = b.impl.NewExporter()
241	}
242
243	return b.exporter
244}
245
246func (b *Bridge) ensureInit() error {
247	if b.initDone {
248		return nil
249	}
250
251	importer := b.getImporter()
252	if importer != nil {
253		err := importer.Init(b.conf)
254		if err != nil {
255			return err
256		}
257	}
258
259	exporter := b.getExporter()
260	if exporter != nil {
261		err := exporter.Init(b.conf)
262		if err != nil {
263			return err
264		}
265	}
266
267	b.initDone = true
268
269	return nil
270}
271
272func (b *Bridge) ImportAll(since time.Time) error {
273	importer := b.getImporter()
274	if importer == nil {
275		return ErrImportNotSupported
276	}
277
278	err := b.ensureConfig()
279	if err != nil {
280		return err
281	}
282
283	err = b.ensureInit()
284	if err != nil {
285		return err
286	}
287
288	return importer.ImportAll(b.repo, since)
289}
290
291func (b *Bridge) ExportAll(since time.Time) error {
292	exporter := b.getExporter()
293	if exporter == nil {
294		return ErrExportNotSupported
295	}
296
297	err := b.ensureConfig()
298	if err != nil {
299		return err
300	}
301
302	err = b.ensureInit()
303	if err != nil {
304		return err
305	}
306
307	return exporter.ExportAll(b.repo, since)
308}