forked from OpenFeign/feign
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathErrorDecoder.java
More file actions
153 lines (138 loc) · 5.48 KB
/
ErrorDecoder.java
File metadata and controls
153 lines (138 loc) · 5.48 KB
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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/*
* Copyright 2013 Netflix, Inc.
*
* 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
*
* http://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 feign.codec;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.Map;
import feign.FeignException;
import feign.Response;
import feign.RetryableException;
import static feign.FeignException.errorStatus;
import static feign.Util.RETRY_AFTER;
import static feign.Util.checkNotNull;
import static java.util.Locale.US;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
/**
* Allows you to massage an exception into a application-specific one. Converting out to a throttle
* exception are examples of this in use.
*
* <p/>Ex:
* <pre>
* class IllegalArgumentExceptionOn404Decoder implements ErrorDecoder {
*
* @Override
* public Exception decode(String methodKey, Response response) {
* if (response.status() == 400)
* throw new IllegalArgumentException("bad zone name");
* return new ErrorDecoder.Default().decode(methodKey, response);
* }
*
* }
* </pre>
*
* <p/><b>Error handling</b>
*
* <p/>Responses where {@link Response#status()} is not in the 2xx
* range are classified as errors, addressed by the {@link ErrorDecoder}. That said, certain RPC
* apis return errors defined in the {@link Response#body()} even on a 200 status. For example, in
* the DynECT api, a job still running condition is returned with a 200 status, encoded in json.
* When scenarios like this occur, you should raise an application-specific exception (which may be
* {@link feign.RetryableException retryable}).
*
* <p/><b>Not Found Semantics</b>
* <p/> It is commonly the case that 404 (Not Found) status has semantic value in HTTP apis. While
* the default behavior is to raise exeception, users can alternatively enable 404 processing via
* {@link feign.Feign.Builder#decode404()}.
*/
public interface ErrorDecoder {
/**
* Implement this method in order to decode an HTTP {@link Response} when {@link
* Response#status()} is not in the 2xx range. Please raise application-specific exceptions where
* possible. If your exception is retryable, wrap or subclass {@link RetryableException}
*
* @param methodKey {@link feign.Feign#configKey} of the java method that invoked the request.
* ex. {@code IAM#getUser()}
* @param response HTTP response where {@link Response#status() status} is greater than or equal
* to {@code 300}.
* @return Exception IOException, if there was a network error reading the response or an
* application-specific exception decoded by the implementation. If the throwable is retryable, it
* should be wrapped, or a subtype of {@link RetryableException}
*/
public Exception decode(String methodKey, Response response);
public static class Default implements ErrorDecoder {
private final RetryAfterDecoder retryAfterDecoder = new RetryAfterDecoder();
@Override
public Exception decode(String methodKey, Response response) {
FeignException exception = errorStatus(methodKey, response);
Date retryAfter = retryAfterDecoder.apply(firstOrNull(response.headers(), RETRY_AFTER));
if (retryAfter != null) {
return new RetryableException(exception.getMessage(), exception, retryAfter);
}
return exception;
}
private <T> T firstOrNull(Map<String, Collection<T>> map, String key) {
if (map.containsKey(key) && !map.get(key).isEmpty()) {
return map.get(key).iterator().next();
}
return null;
}
}
/**
* Decodes a {@link feign.Util#RETRY_AFTER} header into an absolute date, if possible. <br> See <a
* href="https://tools.ietf.org/html/rfc2616#section-14.37">Retry-After format</a>
*/
static class RetryAfterDecoder {
static final DateFormat
RFC822_FORMAT =
new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss 'GMT'", US);
private final DateFormat rfc822Format;
RetryAfterDecoder() {
this(RFC822_FORMAT);
}
RetryAfterDecoder(DateFormat rfc822Format) {
this.rfc822Format = checkNotNull(rfc822Format, "rfc822Format");
}
protected long currentTimeMillis() {
return System.currentTimeMillis();
}
/**
* returns a date that corresponds to the first time a request can be retried.
*
* @param retryAfter String in <a href="https://tools.ietf.org/html/rfc2616#section-14.37"
* >Retry-After format</a>
*/
public Date apply(String retryAfter) {
if (retryAfter == null) {
return null;
}
if (retryAfter.matches("^[0-9]+$")) {
long deltaMillis = SECONDS.toMillis(Long.parseLong(retryAfter));
return new Date(currentTimeMillis() + deltaMillis);
}
synchronized (rfc822Format) {
try {
return rfc822Format.parse(retryAfter);
} catch (ParseException ignored) {
return null;
}
}
}
}
}