/
product.go
80 lines (67 loc) · 2.16 KB
/
product.go
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// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
package app
import (
"fmt"
"strings"
)
type Product interface {
Start() error
Stop() error
}
type ProductManifest struct {
Initializer func(*Server, map[ServiceKey]interface{}) (Product, error)
Dependencies map[ServiceKey]struct{}
}
var products = make(map[string]ProductManifest)
func RegisterProduct(name string, m ProductManifest) {
products[name] = m
}
func (s *Server) initializeProducts(
productMap map[string]ProductManifest,
serviceMap map[ServiceKey]interface{},
) error {
// create a product map to consume
pmap := make(map[string]struct{})
for name := range productMap {
pmap[name] = struct{}{}
}
// We figure out the initialization order by trial and error fashion hence maxTry
// is the maximum possible trials of initialization attempts. The order is not
// determined elsewhere therefore we do a on the fly sorting here. Which means the
// initialization order will be resolved during the loop.
maxTry := len(pmap) * len(pmap)
for len(pmap) > 0 && maxTry != 0 {
initLoop:
for product := range pmap {
manifest := productMap[product]
// we have dependencies defined. Here we check if the serviceMap
// has all the dependencies registered. If not, we continue to the
// loop to let other products initialize and register their services
// if they have any.
for key := range manifest.Dependencies {
if _, ok := serviceMap[key]; !ok {
maxTry--
continue initLoop
}
}
// some products can register themselves/their services
initializer := manifest.Initializer
prod, err := initializer(s, serviceMap)
if err != nil {
return fmt.Errorf("error initializing product %q: %w", product, err)
}
s.products[product] = prod
// we remove this product from the map to not try to initialize it again
delete(pmap, product)
}
}
if maxTry == 0 && len(pmap) != 0 {
var products string
for p := range pmap {
products = strings.Join([]string{products, fmt.Sprintf("%q", p)}, " ")
}
return fmt.Errorf("could not initialize product(s) due to circular dependency: %s", products)
}
return nil
}