| 1 | var AWS = require('./core');
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| 2 | require('./http');
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| 3 | var inherit = AWS.util.inherit;
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| 4 |
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| 5 | /**
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| 6 | * Represents a metadata service available on EC2 instances. Using the
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| 7 | * {request} method, you can receieve metadata about any available resource
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| 8 | * on the metadata service.
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| 9 | *
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| 10 | * You can disable the use of the IMDS by setting the AWS_EC2_METADATA_DISABLED
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| 11 | * environment variable to a truthy value.
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| 12 | *
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| 13 | * @!attribute [r] httpOptions
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| 14 | * @return [map] a map of options to pass to the underlying HTTP request:
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| 15 | *
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| 16 | * * **timeout** (Number) — a timeout value in milliseconds to wait
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| 17 | * before aborting the connection. Set to 0 for no timeout.
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| 18 | *
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| 19 | * @!macro nobrowser
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| 20 | */
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| 21 | AWS.MetadataService = inherit({
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| 22 | /**
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| 23 | * @return [String] the hostname of the instance metadata service
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| 24 | */
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| 25 | host: '169.254.169.254',
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| 26 |
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| 27 | /**
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| 28 | * @!ignore
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| 29 | */
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| 30 |
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| 31 | /**
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| 32 | * Default HTTP options. By default, the metadata service is set to not
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| 33 | * timeout on long requests. This means that on non-EC2 machines, this
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| 34 | * request will never return. If you are calling this operation from an
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| 35 | * environment that may not always run on EC2, set a `timeout` value so
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| 36 | * the SDK will abort the request after a given number of milliseconds.
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| 37 | */
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| 38 | httpOptions: { timeout: 0 },
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| 39 |
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| 40 | /**
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| 41 | * Creates a new MetadataService object with a given set of options.
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| 42 | *
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| 43 | * @option options host [String] the hostname of the instance metadata
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| 44 | * service
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| 45 | * @option options httpOptions [map] a map of options to pass to the
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| 46 | * underlying HTTP request:
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| 47 | *
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| 48 | * * **timeout** (Number) — a timeout value in milliseconds to wait
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| 49 | * before aborting the connection. Set to 0 for no timeout.
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| 50 | * @option options maxRetries [Integer] the maximum number of retries to
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| 51 | * perform for timeout errors
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| 52 | * @option options retryDelayOptions [map] A set of options to configure the
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| 53 | * retry delay on retryable errors. See AWS.Config for details.
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| 54 | */
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| 55 | constructor: function MetadataService(options) {
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| 56 | AWS.util.update(this, options);
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| 57 | },
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| 58 |
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| 59 | /**
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| 60 | * Sends a request to the instance metadata service for a given resource.
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| 61 | *
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| 62 | * @param path [String] the path of the resource to get
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| 63 | * @callback callback function(err, data)
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| 64 | * Called when a response is available from the service.
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| 65 | * @param err [Error, null] if an error occurred, this value will be set
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| 66 | * @param data [String, null] if the request was successful, the body of
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| 67 | * the response
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| 68 | */
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| 69 | request: function request(path, callback) {
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| 70 | if (process.env[AWS.util.imdsDisabledEnv]) {
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| 71 | callback(new Error('EC2 Instance Metadata Service access disabled'));
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| 72 | return;
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| 73 | }
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| 74 |
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| 75 | path = path || '/';
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| 76 | var httpRequest = new AWS.HttpRequest('http://' + this.host + path);
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| 77 | httpRequest.method = 'GET';
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| 78 | AWS.util.handleRequestWithRetries(httpRequest, this, callback);
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| 79 | },
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| 80 |
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| 81 | /**
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| 82 | * @api private
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| 83 | */
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| 84 | loadCredentialsCallbacks: [],
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| 85 |
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| 86 | /**
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| 87 | * Loads a set of credentials stored in the instance metadata service
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| 88 | *
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| 89 | * @api private
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| 90 | * @callback callback function(err, credentials)
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| 91 | * Called when credentials are loaded from the resource
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| 92 | * @param err [Error] if an error occurred, this value will be set
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| 93 | * @param credentials [Object] the raw JSON object containing all
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| 94 | * metadata from the credentials resource
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| 95 | */
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| 96 | loadCredentials: function loadCredentials(callback) {
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| 97 | var self = this;
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| 98 | var basePath = '/latest/meta-data/iam/security-credentials/';
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| 99 | self.loadCredentialsCallbacks.push(callback);
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| 100 | if (self.loadCredentialsCallbacks.length > 1) { return; }
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| 101 |
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| 102 | function callbacks(err, creds) {
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| 103 | var cb;
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| 104 | while ((cb = self.loadCredentialsCallbacks.shift()) !== undefined) {
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| 105 | cb(err, creds);
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| 106 | }
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| 107 | }
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| 108 |
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| 109 | self.request(basePath, function (err, roleName) {
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| 110 | if (err) callbacks(err);
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| 111 | else {
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| 112 | roleName = roleName.split('\n')[0]; // grab first (and only) role
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| 113 | self.request(basePath + roleName, function (credErr, credData) {
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| 114 | if (credErr) callbacks(credErr);
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| 115 | else {
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| 116 | try {
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| 117 | var credentials = JSON.parse(credData);
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| 118 | callbacks(null, credentials);
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| 119 | } catch (parseError) {
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| 120 | callbacks(parseError);
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| 121 | }
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| 122 | }
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| 123 | });
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| 124 | }
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| 125 | });
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| 126 | }
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| 127 | });
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| 128 |
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| 129 | /**
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| 130 | * @api private
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| 131 | */
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| 132 | module.exports = AWS.MetadataService;
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