1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
// 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 (
"fmt"
"io/ioutil"
"log"
"os"
"cloud.google.com/go/storage"
)
// pkgSource represents the source from which the Nix package set used
// by Nixery is imported. Users configure the source by setting one of
// the supported environment variables.
type PkgSource struct {
srcType string
args string
}
// Convert the package source into the representation required by Nix.
func (p *PkgSource) Render(tag string) string {
// The 'git' source requires a tag to be present.
if p.srcType == "git" {
if tag == "latest" || tag == "" {
tag = "master"
}
return fmt.Sprintf("git!%s!%s", p.args, tag)
}
return fmt.Sprintf("%s!%s", p.srcType, p.args)
}
// Retrieve a package source from the environment. If no source is
// specified, the Nix code will default to a recent NixOS channel.
func pkgSourceFromEnv() *PkgSource {
if channel := os.Getenv("NIXERY_CHANNEL"); channel != "" {
log.Printf("Using Nix package set from Nix channel %q\n", channel)
return &PkgSource{
srcType: "nixpkgs",
args: channel,
}
}
if git := os.Getenv("NIXERY_PKGS_REPO"); git != "" {
log.Printf("Using Nix package set from git repository at %q\n", git)
return &PkgSource{
srcType: "git",
args: git,
}
}
if path := os.Getenv("NIXERY_PKGS_PATH"); path != "" {
log.Printf("Using Nix package set from path %q\n", path)
return &PkgSource{
srcType: "path",
args: path,
}
}
return nil
}
// Load (optional) GCS bucket signing data from the GCS_SIGNING_KEY and
// GCS_SIGNING_ACCOUNT envvars.
func signingOptsFromEnv() *storage.SignedURLOptions {
path := os.Getenv("GCS_SIGNING_KEY")
id := os.Getenv("GCS_SIGNING_ACCOUNT")
if path == "" || id == "" {
log.Println("GCS URL signing disabled")
return nil
}
log.Printf("GCS URL signing enabled with account %q\n", id)
k, err := ioutil.ReadFile(path)
if err != nil {
log.Fatalf("Failed to read GCS signing key: %s\n", err)
}
return &storage.SignedURLOptions{
GoogleAccessID: id,
PrivateKey: k,
Method: "GET",
}
}
func getConfig(key, desc string) string {
value := os.Getenv(key)
if value == "" {
log.Fatalln(desc + " must be specified")
}
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
WebDir string
}
func FromEnv() *Config {
return &Config{
Bucket: getConfig("BUCKET", "GCS bucket for layer storage"),
Port: getConfig("PORT", "HTTP port"),
Pkgs: pkgSourceFromEnv(),
Signing: signingOptsFromEnv(),
WebDir: getConfig("WEB_DIR", "Static web file dir"),
}
}
|
