linode.go raw
1 // Package linode implements a DNS provider for solving the DNS-01 challenge using Linode DNS and Linode's APIv4
2 package linode
3
4 import (
5 "context"
6 "encoding/json"
7 "errors"
8 "fmt"
9 "net/http"
10 "time"
11
12 "github.com/go-acme/lego/v4/challenge"
13 "github.com/go-acme/lego/v4/challenge/dns01"
14 "github.com/go-acme/lego/v4/platform/config/env"
15 "github.com/go-acme/lego/v4/providers/dns/internal/clientdebug"
16 "github.com/go-acme/lego/v4/providers/dns/internal/useragent"
17 "github.com/linode/linodego"
18 "golang.org/x/oauth2"
19 )
20
21 // Environment variables names.
22 const (
23 envNamespace = "LINODE_"
24
25 EnvToken = envNamespace + "TOKEN"
26
27 EnvTTL = envNamespace + "TTL"
28 EnvPropagationTimeout = envNamespace + "PROPAGATION_TIMEOUT"
29 EnvPollingInterval = envNamespace + "POLLING_INTERVAL"
30 EnvHTTPTimeout = envNamespace + "HTTP_TIMEOUT"
31 )
32
33 const (
34 minTTL = 300
35 dnsUpdateFreqMins = 15
36 dnsUpdateFudgeSecs = 120
37 )
38
39 var _ challenge.ProviderTimeout = (*DNSProvider)(nil)
40
41 // Config is used to configure the creation of the DNSProvider.
42 type Config struct {
43 Token string
44 PropagationTimeout time.Duration
45 PollingInterval time.Duration
46 TTL int
47 HTTPTimeout time.Duration
48 }
49
50 // NewDefaultConfig returns a default configuration for the DNSProvider.
51 func NewDefaultConfig() *Config {
52 return &Config{
53 TTL: env.GetOrDefaultInt(EnvTTL, minTTL),
54 PropagationTimeout: env.GetOrDefaultSecond(EnvPropagationTimeout, 120*time.Second),
55 PollingInterval: env.GetOrDefaultSecond(EnvPollingInterval, 15*time.Second),
56 HTTPTimeout: env.GetOrDefaultSecond(EnvHTTPTimeout, 30*time.Second),
57 }
58 }
59
60 type hostedZoneInfo struct {
61 domainID int
62 resourceName string
63 }
64
65 // DNSProvider implements the challenge.Provider interface.
66 type DNSProvider struct {
67 config *Config
68 client *linodego.Client
69 }
70
71 // NewDNSProvider returns a DNSProvider instance configured for Linode.
72 // Credentials must be passed in the environment variable: LINODE_TOKEN.
73 func NewDNSProvider() (*DNSProvider, error) {
74 values, err := env.Get(EnvToken)
75 if err != nil {
76 return nil, fmt.Errorf("linode: %w", err)
77 }
78
79 config := NewDefaultConfig()
80 config.Token = values[EnvToken]
81
82 return NewDNSProviderConfig(config)
83 }
84
85 // NewDNSProviderConfig return a DNSProvider instance configured for Linode.
86 func NewDNSProviderConfig(config *Config) (*DNSProvider, error) {
87 if config == nil {
88 return nil, errors.New("linode: the configuration of the DNS provider is nil")
89 }
90
91 if config.Token == "" {
92 return nil, errors.New("linode: Linode Access Token missing")
93 }
94
95 if config.TTL < minTTL {
96 return nil, fmt.Errorf("linode: invalid TTL, TTL (%d) must be greater than %d", config.TTL, minTTL)
97 }
98
99 oauth2Client := &http.Client{
100 Timeout: config.HTTPTimeout,
101 Transport: &oauth2.Transport{
102 Source: oauth2.StaticTokenSource(&oauth2.Token{AccessToken: config.Token}),
103 },
104 }
105
106 client := linodego.NewClient(clientdebug.Wrap(oauth2Client))
107 client.SetUserAgent(useragent.Get())
108
109 return &DNSProvider{config: config, client: &client}, nil
110 }
111
112 // Timeout returns the timeout and interval to use when checking for DNS propagation.
113 // Adjusting here to cope with spikes in propagation times.
114 func (d *DNSProvider) Timeout() (time.Duration, time.Duration) {
115 timeout := d.config.PropagationTimeout
116 if d.config.PropagationTimeout <= 0 {
117 // Since Linode only updates their zone files every X minutes, we need
118 // to figure out how many minutes we have to wait until we hit the next
119 // interval of X. We then wait another couple of minutes, just to be
120 // safe. Hopefully at some point during all of this, the record will
121 // have propagated throughout Linode's network.
122 minsRemaining := dnsUpdateFreqMins - (time.Now().Minute() % dnsUpdateFreqMins)
123
124 timeout = (time.Duration(minsRemaining) * time.Minute) +
125 (minTTL * time.Second) +
126 (dnsUpdateFudgeSecs * time.Second)
127 }
128
129 return timeout, d.config.PollingInterval
130 }
131
132 // Present creates a TXT record using the specified parameters.
133 func (d *DNSProvider) Present(domain, token, keyAuth string) error {
134 ctx := context.Background()
135
136 info := dns01.GetChallengeInfo(domain, keyAuth)
137
138 zone, err := d.getHostedZoneInfo(ctx, info.EffectiveFQDN)
139 if err != nil {
140 return err
141 }
142
143 createOpts := linodego.DomainRecordCreateOptions{
144 Name: dns01.UnFqdn(info.EffectiveFQDN),
145 Target: info.Value,
146 TTLSec: d.config.TTL,
147 Type: linodego.RecordTypeTXT,
148 }
149
150 _, err = d.client.CreateDomainRecord(ctx, zone.domainID, createOpts)
151
152 return err
153 }
154
155 // CleanUp removes the TXT record matching the specified parameters.
156 func (d *DNSProvider) CleanUp(domain, token, keyAuth string) error {
157 ctx := context.Background()
158
159 info := dns01.GetChallengeInfo(domain, keyAuth)
160
161 zone, err := d.getHostedZoneInfo(ctx, info.EffectiveFQDN)
162 if err != nil {
163 return err
164 }
165
166 // Get all TXT records for the specified domain.
167 listOpts := linodego.NewListOptions(0, `{"type":"TXT"}`)
168
169 resources, err := d.client.ListDomainRecords(ctx, zone.domainID, listOpts)
170 if err != nil {
171 return err
172 }
173
174 // Remove the specified resource, if it exists.
175 for _, resource := range resources {
176 if (resource.Name == dns01.UnFqdn(info.EffectiveFQDN) || resource.Name == zone.resourceName) &&
177 resource.Target == info.Value {
178 if err := d.client.DeleteDomainRecord(ctx, zone.domainID, resource.ID); err != nil {
179 return err
180 }
181 }
182 }
183
184 return nil
185 }
186
187 func (d *DNSProvider) getHostedZoneInfo(ctx context.Context, fqdn string) (*hostedZoneInfo, error) {
188 // Lookup the zone that handles the specified FQDN.
189 authZone, err := dns01.FindZoneByFqdn(fqdn)
190 if err != nil {
191 return nil, fmt.Errorf("could not find zone: %w", err)
192 }
193
194 // Query the authority zone.
195 filter, err := json.Marshal(map[string]string{"domain": dns01.UnFqdn(authZone)})
196 if err != nil {
197 return nil, fmt.Errorf("failed to create JSON filter: %w", err)
198 }
199
200 listOpts := linodego.NewListOptions(0, string(filter))
201
202 domains, err := d.client.ListDomains(ctx, listOpts)
203 if err != nil {
204 return nil, err
205 }
206
207 if len(domains) == 0 {
208 return nil, errors.New("domain not found")
209 }
210
211 subDomain, err := dns01.ExtractSubDomain(fqdn, authZone)
212 if err != nil {
213 return nil, err
214 }
215
216 return &hostedZoneInfo{
217 domainID: domains[0].ID,
218 resourceName: subDomain,
219 }, nil
220 }
221