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bae9f6d2 JC |
1 | package getter |
2 | ||
3 | import ( | |
4 | "encoding/xml" | |
5 | "fmt" | |
6 | "io" | |
7 | "io/ioutil" | |
8 | "net/http" | |
9 | "net/url" | |
10 | "os" | |
11 | "path/filepath" | |
12 | "strings" | |
13 | ) | |
14 | ||
15 | // HttpGetter is a Getter implementation that will download from an HTTP | |
16 | // endpoint. | |
17 | // | |
18 | // For file downloads, HTTP is used directly. | |
19 | // | |
20 | // The protocol for downloading a directory from an HTTP endpoing is as follows: | |
21 | // | |
22 | // An HTTP GET request is made to the URL with the additional GET parameter | |
23 | // "terraform-get=1". This lets you handle that scenario specially if you | |
24 | // wish. The response must be a 2xx. | |
25 | // | |
26 | // First, a header is looked for "X-Terraform-Get" which should contain | |
27 | // a source URL to download. | |
28 | // | |
29 | // If the header is not present, then a meta tag is searched for named | |
30 | // "terraform-get" and the content should be a source URL. | |
31 | // | |
32 | // The source URL, whether from the header or meta tag, must be a fully | |
33 | // formed URL. The shorthand syntax of "github.com/foo/bar" or relative | |
34 | // paths are not allowed. | |
35 | type HttpGetter struct { | |
36 | // Netrc, if true, will lookup and use auth information found | |
37 | // in the user's netrc file if available. | |
38 | Netrc bool | |
39 | } | |
40 | ||
41 | func (g *HttpGetter) ClientMode(u *url.URL) (ClientMode, error) { | |
42 | if strings.HasSuffix(u.Path, "/") { | |
43 | return ClientModeDir, nil | |
44 | } | |
45 | return ClientModeFile, nil | |
46 | } | |
47 | ||
48 | func (g *HttpGetter) Get(dst string, u *url.URL) error { | |
49 | // Copy the URL so we can modify it | |
50 | var newU url.URL = *u | |
51 | u = &newU | |
52 | ||
53 | if g.Netrc { | |
54 | // Add auth from netrc if we can | |
55 | if err := addAuthFromNetrc(u); err != nil { | |
56 | return err | |
57 | } | |
58 | } | |
59 | ||
60 | // Add terraform-get to the parameter. | |
61 | q := u.Query() | |
62 | q.Add("terraform-get", "1") | |
63 | u.RawQuery = q.Encode() | |
64 | ||
65 | // Get the URL | |
66 | resp, err := http.Get(u.String()) | |
67 | if err != nil { | |
68 | return err | |
69 | } | |
70 | defer resp.Body.Close() | |
71 | if resp.StatusCode < 200 || resp.StatusCode >= 300 { | |
72 | return fmt.Errorf("bad response code: %d", resp.StatusCode) | |
73 | } | |
74 | ||
75 | // Extract the source URL | |
76 | var source string | |
77 | if v := resp.Header.Get("X-Terraform-Get"); v != "" { | |
78 | source = v | |
79 | } else { | |
80 | source, err = g.parseMeta(resp.Body) | |
81 | if err != nil { | |
82 | return err | |
83 | } | |
84 | } | |
85 | if source == "" { | |
86 | return fmt.Errorf("no source URL was returned") | |
87 | } | |
88 | ||
89 | // If there is a subdir component, then we download the root separately | |
90 | // into a temporary directory, then copy over the proper subdir. | |
91 | source, subDir := SourceDirSubdir(source) | |
92 | if subDir == "" { | |
93 | return Get(dst, source) | |
94 | } | |
95 | ||
96 | // We have a subdir, time to jump some hoops | |
97 | return g.getSubdir(dst, source, subDir) | |
98 | } | |
99 | ||
100 | func (g *HttpGetter) GetFile(dst string, u *url.URL) error { | |
101 | resp, err := http.Get(u.String()) | |
102 | if err != nil { | |
103 | return err | |
104 | } | |
105 | defer resp.Body.Close() | |
106 | if resp.StatusCode != 200 { | |
107 | return fmt.Errorf("bad response code: %d", resp.StatusCode) | |
108 | } | |
109 | ||
110 | // Create all the parent directories | |
111 | if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil { | |
112 | return err | |
113 | } | |
114 | ||
115 | f, err := os.Create(dst) | |
116 | if err != nil { | |
117 | return err | |
118 | } | |
119 | defer f.Close() | |
120 | ||
121 | _, err = io.Copy(f, resp.Body) | |
122 | return err | |
123 | } | |
124 | ||
125 | // getSubdir downloads the source into the destination, but with | |
126 | // the proper subdir. | |
127 | func (g *HttpGetter) getSubdir(dst, source, subDir string) error { | |
128 | // Create a temporary directory to store the full source | |
129 | td, err := ioutil.TempDir("", "tf") | |
130 | if err != nil { | |
131 | return err | |
132 | } | |
133 | defer os.RemoveAll(td) | |
134 | ||
135 | // Download that into the given directory | |
136 | if err := Get(td, source); err != nil { | |
137 | return err | |
138 | } | |
139 | ||
140 | // Make sure the subdir path actually exists | |
141 | sourcePath := filepath.Join(td, subDir) | |
142 | if _, err := os.Stat(sourcePath); err != nil { | |
143 | return fmt.Errorf( | |
144 | "Error downloading %s: %s", source, err) | |
145 | } | |
146 | ||
147 | // Copy the subdirectory into our actual destination. | |
148 | if err := os.RemoveAll(dst); err != nil { | |
149 | return err | |
150 | } | |
151 | ||
152 | // Make the final destination | |
153 | if err := os.MkdirAll(dst, 0755); err != nil { | |
154 | return err | |
155 | } | |
156 | ||
157 | return copyDir(dst, sourcePath, false) | |
158 | } | |
159 | ||
160 | // parseMeta looks for the first meta tag in the given reader that | |
161 | // will give us the source URL. | |
162 | func (g *HttpGetter) parseMeta(r io.Reader) (string, error) { | |
163 | d := xml.NewDecoder(r) | |
164 | d.CharsetReader = charsetReader | |
165 | d.Strict = false | |
166 | var err error | |
167 | var t xml.Token | |
168 | for { | |
169 | t, err = d.Token() | |
170 | if err != nil { | |
171 | if err == io.EOF { | |
172 | err = nil | |
173 | } | |
174 | return "", err | |
175 | } | |
176 | if e, ok := t.(xml.StartElement); ok && strings.EqualFold(e.Name.Local, "body") { | |
177 | return "", nil | |
178 | } | |
179 | if e, ok := t.(xml.EndElement); ok && strings.EqualFold(e.Name.Local, "head") { | |
180 | return "", nil | |
181 | } | |
182 | e, ok := t.(xml.StartElement) | |
183 | if !ok || !strings.EqualFold(e.Name.Local, "meta") { | |
184 | continue | |
185 | } | |
186 | if attrValue(e.Attr, "name") != "terraform-get" { | |
187 | continue | |
188 | } | |
189 | if f := attrValue(e.Attr, "content"); f != "" { | |
190 | return f, nil | |
191 | } | |
192 | } | |
193 | } | |
194 | ||
195 | // attrValue returns the attribute value for the case-insensitive key | |
196 | // `name', or the empty string if nothing is found. | |
197 | func attrValue(attrs []xml.Attr, name string) string { | |
198 | for _, a := range attrs { | |
199 | if strings.EqualFold(a.Name.Local, name) { | |
200 | return a.Value | |
201 | } | |
202 | } | |
203 | return "" | |
204 | } | |
205 | ||
206 | // charsetReader returns a reader for the given charset. Currently | |
207 | // it only supports UTF-8 and ASCII. Otherwise, it returns a meaningful | |
208 | // error which is printed by go get, so the user can find why the package | |
209 | // wasn't downloaded if the encoding is not supported. Note that, in | |
210 | // order to reduce potential errors, ASCII is treated as UTF-8 (i.e. characters | |
211 | // greater than 0x7f are not rejected). | |
212 | func charsetReader(charset string, input io.Reader) (io.Reader, error) { | |
213 | switch strings.ToLower(charset) { | |
214 | case "ascii": | |
215 | return input, nil | |
216 | default: | |
217 | return nil, fmt.Errorf("can't decode XML document using charset %q", charset) | |
218 | } | |
219 | } |