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// Copyright 2019 Google LLC
//
// 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
//
// https://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 config implements structures to store Nixery's configuration at
// runtime as well as the logic for instantiating this configuration from the
// environment.
package config
import (
"io/ioutil"
"os"
"cloud.google.com/go/storage"
log "github.com/sirupsen/logrus"
"golang.org/x/oauth2/google"
)
// Configure GCS URL signing in the presence of a service account key
// (toggled if the user has set GOOGLE_APPLICATION_CREDENTIALS).
func signingOptsFromEnv() *storage.SignedURLOptions {
path := os.Getenv("GOOGLE_APPLICATION_CREDENTIALS")
if path == "" {
return nil
}
key, err := ioutil.ReadFile(path)
if err != nil {
log.WithError(err).WithField("file", path).Fatal("failed to read service account key")
}
conf, err := google.JWTConfigFromJSON(key)
if err != nil {
log.WithError(err).WithField("file", path).Fatal("failed to parse service account key")
}
log.WithField("account", conf.Email).Info("GCS URL signing enabled")
return &storage.SignedURLOptions{
Scheme: storage.SigningSchemeV4,
GoogleAccessID: conf.Email,
PrivateKey: conf.PrivateKey,
Method: "GET",
}
}
func getConfig(key, desc, def string) string {
value := os.Getenv(key)
if value == "" && def == "" {
log.WithFields(log.Fields{
"option": key,
"description": desc,
}).Fatal("missing required configuration envvar")
} else if value == "" {
return def
}
return value
}
// Config holds the Nixery configuration options.
type Config struct {
Bucket string // GCS bucket to cache & serve layers
Signing *storage.SignedURLOptions // Signing options to use for GCS URLs
Port string // Port on which to launch HTTP server
Pkgs PkgSource // Source for Nix package set
Timeout string // Timeout for a single Nix builder (seconds)
WebDir string // Directory with static web assets
PopUrl string // URL to the Nix package popularity count
}
func FromEnv() (Config, error) {
pkgs, err := pkgSourceFromEnv()
if err != nil {
return Config{}, err
}
return Config{
Bucket: getConfig("BUCKET", "GCS bucket for layer storage", ""),
Port: getConfig("PORT", "HTTP port", ""),
Pkgs: pkgs,
Signing: signingOptsFromEnv(),
Timeout: getConfig("NIX_TIMEOUT", "Nix builder timeout", "60"),
WebDir: getConfig("WEB_DIR", "Static web file dir", ""),
PopUrl: os.Getenv("NIX_POPULARITY_URL"),
}, nil
}
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