diff options
Diffstat (limited to 'vendor/github.com/hashicorp/go-retryablehttp')
4 files changed, 907 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/LICENSE b/vendor/github.com/hashicorp/go-retryablehttp/LICENSE new file mode 100644 index 0000000..e87a115 --- /dev/null +++ b/vendor/github.com/hashicorp/go-retryablehttp/LICENSE @@ -0,0 +1,363 @@ +Mozilla Public License, version 2.0 + +1. Definitions + +1.1. "Contributor" + + means each individual or legal entity that creates, contributes to the + creation of, or owns Covered Software. + +1.2. "Contributor Version" + + means the combination of the Contributions of others (if any) used by a + Contributor and that particular Contributor's Contribution. + +1.3. "Contribution" + + means Covered Software of a particular Contributor. + +1.4. "Covered Software" + + means Source Code Form to which the initial Contributor has attached the + notice in Exhibit A, the Executable Form of such Source Code Form, and + Modifications of such Source Code Form, in each case including portions + thereof. + +1.5. "Incompatible With Secondary Licenses" + means + + a. that the initial Contributor has attached the notice described in + Exhibit B to the Covered Software; or + + b. that the Covered Software was made available under the terms of + version 1.1 or earlier of the License, but not also under the terms of + a Secondary License. + +1.6. "Executable Form" + + means any form of the work other than Source Code Form. + +1.7. "Larger Work" + + means a work that combines Covered Software with other material, in a + separate file or files, that is not Covered Software. + +1.8. "License" + + means this document. + +1.9. "Licensable" + + means having the right to grant, to the maximum extent possible, whether + at the time of the initial grant or subsequently, any and all of the + rights conveyed by this License. + +1.10. "Modifications" + + means any of the following: + + a. any file in Source Code Form that results from an addition to, + deletion from, or modification of the contents of Covered Software; or + + b. any new file in Source Code Form that contains any Covered Software. + +1.11. "Patent Claims" of a Contributor + + means any patent claim(s), including without limitation, method, + process, and apparatus claims, in any patent Licensable by such + Contributor that would be infringed, but for the grant of the License, + by the making, using, selling, offering for sale, having made, import, + or transfer of either its Contributions or its Contributor Version. + +1.12. "Secondary License" + + means either the GNU General Public License, Version 2.0, the GNU Lesser + General Public License, Version 2.1, the GNU Affero General Public + License, Version 3.0, or any later versions of those licenses. + +1.13. "Source Code Form" + + means the form of the work preferred for making modifications. + +1.14. "You" (or "Your") + + means an individual or a legal entity exercising rights under this + License. For legal entities, "You" includes any entity that controls, is + controlled by, or is under common control with You. For purposes of this + definition, "control" means (a) the power, direct or indirect, to cause + the direction or management of such entity, whether by contract or + otherwise, or (b) ownership of more than fifty percent (50%) of the + outstanding shares or beneficial ownership of such entity. + + +2. License Grants and Conditions + +2.1. Grants + + Each Contributor hereby grants You a world-wide, royalty-free, + non-exclusive license: + + a. under intellectual property rights (other than patent or trademark) + Licensable by such Contributor to use, reproduce, make available, + modify, display, perform, distribute, and otherwise exploit its + Contributions, either on an unmodified basis, with Modifications, or + as part of a Larger Work; and + + b. under Patent Claims of such Contributor to make, use, sell, offer for + sale, have made, import, and otherwise transfer either its + Contributions or its Contributor Version. + +2.2. Effective Date + + The licenses granted in Section 2.1 with respect to any Contribution + become effective for each Contribution on the date the Contributor first + distributes such Contribution. + +2.3. Limitations on Grant Scope + + The licenses granted in this Section 2 are the only rights granted under + this License. No additional rights or licenses will be implied from the + distribution or licensing of Covered Software under this License. + Notwithstanding Section 2.1(b) above, no patent license is granted by a + Contributor: + + a. for any code that a Contributor has removed from Covered Software; or + + b. for infringements caused by: (i) Your and any other third party's + modifications of Covered Software, or (ii) the combination of its + Contributions with other software (except as part of its Contributor + Version); or + + c. under Patent Claims infringed by Covered Software in the absence of + its Contributions. + + This License does not grant any rights in the trademarks, service marks, + or logos of any Contributor (except as may be necessary to comply with + the notice requirements in Section 3.4). + +2.4. Subsequent Licenses + + No Contributor makes additional grants as a result of Your choice to + distribute the Covered Software under a subsequent version of this + License (see Section 10.2) or under the terms of a Secondary License (if + permitted under the terms of Section 3.3). + +2.5. Representation + + Each Contributor represents that the Contributor believes its + Contributions are its original creation(s) or it has sufficient rights to + grant the rights to its Contributions conveyed by this License. + +2.6. Fair Use + + This License is not intended to limit any rights You have under + applicable copyright doctrines of fair use, fair dealing, or other + equivalents. + +2.7. Conditions + + Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in + Section 2.1. + + +3. Responsibilities + +3.1. Distribution of Source Form + + All distribution of Covered Software in Source Code Form, including any + Modifications that You create or to which You contribute, must be under + the terms of this License. You must inform recipients that the Source + Code Form of the Covered Software is governed by the terms of this + License, and how they can obtain a copy of this License. You may not + attempt to alter or restrict the recipients' rights in the Source Code + Form. + +3.2. Distribution of Executable Form + + If You distribute Covered Software in Executable Form then: + + a. such Covered Software must also be made available in Source Code Form, + as described in Section 3.1, and You must inform recipients of the + Executable Form how they can obtain a copy of such Source Code Form by + reasonable means in a timely manner, at a charge no more than the cost + of distribution to the recipient; and + + b. You may distribute such Executable Form under the terms of this + License, or sublicense it under different terms, provided that the + license for the Executable Form does not attempt to limit or alter the + recipients' rights in the Source Code Form under this License. + +3.3. Distribution of a Larger Work + + You may create and distribute a Larger Work under terms of Your choice, + provided that You also comply with the requirements of this License for + the Covered Software. If the Larger Work is a combination of Covered + Software with a work governed by one or more Secondary Licenses, and the + Covered Software is not Incompatible With Secondary Licenses, this + License permits You to additionally distribute such Covered Software + under the terms of such Secondary License(s), so that the recipient of + the Larger Work may, at their option, further distribute the Covered + Software under the terms of either this License or such Secondary + License(s). + +3.4. Notices + + You may not remove or alter the substance of any license notices + (including copyright notices, patent notices, disclaimers of warranty, or + limitations of liability) contained within the Source Code Form of the + Covered Software, except that You may alter any license notices to the + extent required to remedy known factual inaccuracies. + +3.5. Application of Additional Terms + + You may choose to offer, and to charge a fee for, warranty, support, + indemnity or liability obligations to one or more recipients of Covered + Software. However, You may do so only on Your own behalf, and not on + behalf of any Contributor. You must make it absolutely clear that any + such warranty, support, indemnity, or liability obligation is offered by + You alone, and You hereby agree to indemnify every Contributor for any + liability incurred by such Contributor as a result of warranty, support, + indemnity or liability terms You offer. You may include additional + disclaimers of warranty and limitations of liability specific to any + jurisdiction. + +4. Inability to Comply Due to Statute or Regulation + + If it is impossible for You to comply with any of the terms of this License + with respect to some or all of the Covered Software due to statute, + judicial order, or regulation then You must: (a) comply with the terms of + this License to the maximum extent possible; and (b) describe the + limitations and the code they affect. Such description must be placed in a + text file included with all distributions of the Covered Software under + this License. Except to the extent prohibited by statute or regulation, + such description must be sufficiently detailed for a recipient of ordinary + skill to be able to understand it. + +5. Termination + +5.1. The rights granted under this License will terminate automatically if You + fail to comply with any of its terms. However, if You become compliant, + then the rights granted under this License from a particular Contributor + are reinstated (a) provisionally, unless and until such Contributor + explicitly and finally terminates Your grants, and (b) on an ongoing + basis, if such Contributor fails to notify You of the non-compliance by + some reasonable means prior to 60 days after You have come back into + compliance. Moreover, Your grants from a particular Contributor are + reinstated on an ongoing basis if such Contributor notifies You of the + non-compliance by some reasonable means, this is the first time You have + received notice of non-compliance with this License from such + Contributor, and You become compliant prior to 30 days after Your receipt + of the notice. + +5.2. If You initiate litigation against any entity by asserting a patent + infringement claim (excluding declaratory judgment actions, + counter-claims, and cross-claims) alleging that a Contributor Version + directly or indirectly infringes any patent, then the rights granted to + You by any and all Contributors for the Covered Software under Section + 2.1 of this License shall terminate. + +5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user + license agreements (excluding distributors and resellers) which have been + validly granted by You or Your distributors under this License prior to + termination shall survive termination. + +6. Disclaimer of Warranty + + Covered Software is provided under this License on an "as is" basis, + without warranty of any kind, either expressed, implied, or statutory, + including, without limitation, warranties that the Covered Software is free + of defects, merchantable, fit for a particular purpose or non-infringing. + The entire risk as to the quality and performance of the Covered Software + is with You. Should any Covered Software prove defective in any respect, + You (not any Contributor) assume the cost of any necessary servicing, + repair, or correction. This disclaimer of warranty constitutes an essential + part of this License. No use of any Covered Software is authorized under + this License except under this disclaimer. + +7. Limitation of Liability + + Under no circumstances and under no legal theory, whether tort (including + negligence), contract, or otherwise, shall any Contributor, or anyone who + distributes Covered Software as permitted above, be liable to You for any + direct, indirect, special, incidental, or consequential damages of any + character including, without limitation, damages for lost profits, loss of + goodwill, work stoppage, computer failure or malfunction, or any and all + other commercial damages or losses, even if such party shall have been + informed of the possibility of such damages. This limitation of liability + shall not apply to liability for death or personal injury resulting from + such party's negligence to the extent applicable law prohibits such + limitation. Some jurisdictions do not allow the exclusion or limitation of + incidental or consequential damages, so this exclusion and limitation may + not apply to You. + +8. Litigation + + Any litigation relating to this License may be brought only in the courts + of a jurisdiction where the defendant maintains its principal place of + business and such litigation shall be governed by laws of that + jurisdiction, without reference to its conflict-of-law provisions. Nothing + in this Section shall prevent a party's ability to bring cross-claims or + counter-claims. + +9. Miscellaneous + + This License represents the complete agreement concerning the subject + matter hereof. If any provision of this License is held to be + unenforceable, such provision shall be reformed only to the extent + necessary to make it enforceable. Any law or regulation which provides that + the language of a contract shall be construed against the drafter shall not + be used to construe this License against a Contributor. + + +10. Versions of the License + +10.1. New Versions + + Mozilla Foundation is the license steward. Except as provided in Section + 10.3, no one other than the license steward has the right to modify or + publish new versions of this License. Each version will be given a + distinguishing version number. + +10.2. Effect of New Versions + + You may distribute the Covered Software under the terms of the version + of the License under which You originally received the Covered Software, + or under the terms of any subsequent version published by the license + steward. + +10.3. Modified Versions + + If you create software not governed by this License, and you want to + create a new license for such software, you may create and use a + modified version of this License if you rename the license and remove + any references to the name of the license steward (except to note that + such modified license differs from this License). + +10.4. Distributing Source Code Form that is Incompatible With Secondary + Licenses If You choose to distribute Source Code Form that is + Incompatible With Secondary Licenses under the terms of this version of + the License, the notice described in Exhibit B of this License must be + attached. + +Exhibit A - Source Code Form License Notice + + This Source Code Form is subject to the + terms of the Mozilla Public License, v. + 2.0. If a copy of the MPL was not + distributed with this file, You can + obtain one at + http://mozilla.org/MPL/2.0/. + +If it is not possible or desirable to put the notice in a particular file, +then You may include the notice in a location (such as a LICENSE file in a +relevant directory) where a recipient would be likely to look for such a +notice. + +You may add additional accurate notices of copyright ownership. + +Exhibit B - "Incompatible With Secondary Licenses" Notice + + This Source Code Form is "Incompatible + With Secondary Licenses", as defined by + the Mozilla Public License, v. 2.0. + diff --git a/vendor/github.com/hashicorp/go-retryablehttp/Makefile b/vendor/github.com/hashicorp/go-retryablehttp/Makefile new file mode 100644 index 0000000..da17640 --- /dev/null +++ b/vendor/github.com/hashicorp/go-retryablehttp/Makefile @@ -0,0 +1,11 @@ +default: test + +test: + go vet ./... + go test -race ./... + +updatedeps: + go get -f -t -u ./... + go get -f -u ./... + +.PHONY: default test updatedeps diff --git a/vendor/github.com/hashicorp/go-retryablehttp/README.md b/vendor/github.com/hashicorp/go-retryablehttp/README.md new file mode 100644 index 0000000..ccdc7e8 --- /dev/null +++ b/vendor/github.com/hashicorp/go-retryablehttp/README.md @@ -0,0 +1,46 @@ +go-retryablehttp +================ + +[][travis] +[][godocs] + +[travis]: http://travis-ci.org/hashicorp/go-retryablehttp +[godocs]: http://godoc.org/github.com/hashicorp/go-retryablehttp + +The `retryablehttp` package provides a familiar HTTP client interface with +automatic retries and exponential backoff. It is a thin wrapper over the +standard `net/http` client library and exposes nearly the same public API. This +makes `retryablehttp` very easy to drop into existing programs. + +`retryablehttp` performs automatic retries under certain conditions. Mainly, if +an error is returned by the client (connection errors, etc.), or if a 500-range +response code is received (except 501), then a retry is invoked after a wait +period. Otherwise, the response is returned and left to the caller to +interpret. + +The main difference from `net/http` is that requests which take a request body +(POST/PUT et. al) can have the body provided in a number of ways (some more or +less efficient) that allow "rewinding" the request body if the initial request +fails so that the full request can be attempted again. See the +[godoc](http://godoc.org/github.com/hashicorp/go-retryablehttp) for more +details. + +Example Use +=========== + +Using this library should look almost identical to what you would do with +`net/http`. The most simple example of a GET request is shown below: + +```go +resp, err := retryablehttp.Get("/foo") +if err != nil { + panic(err) +} +``` + +The returned response object is an `*http.Response`, the same thing you would +usually get from `net/http`. Had the request failed one or more times, the above +call would block and retry with exponential backoff. + +For more usage and examples see the +[godoc](http://godoc.org/github.com/hashicorp/go-retryablehttp). diff --git a/vendor/github.com/hashicorp/go-retryablehttp/client.go b/vendor/github.com/hashicorp/go-retryablehttp/client.go new file mode 100644 index 0000000..c016939 --- /dev/null +++ b/vendor/github.com/hashicorp/go-retryablehttp/client.go @@ -0,0 +1,487 @@ +// The retryablehttp package provides a familiar HTTP client interface with +// automatic retries and exponential backoff. It is a thin wrapper over the +// standard net/http client library and exposes nearly the same public API. +// This makes retryablehttp very easy to drop into existing programs. +// +// retryablehttp performs automatic retries under certain conditions. Mainly, if +// an error is returned by the client (connection errors etc), or if a 500-range +// response is received, then a retry is invoked. Otherwise, the response is +// returned and left to the caller to interpret. +// +// Requests which take a request body should provide a non-nil function +// parameter. The best choice is to provide either a function satisfying +// ReaderFunc which provides multiple io.Readers in an efficient manner, a +// *bytes.Buffer (the underlying raw byte slice will be used) or a raw byte +// slice. As it is a reference type, and we will wrap it as needed by readers, +// we can efficiently re-use the request body without needing to copy it. If an +// io.Reader (such as a *bytes.Reader) is provided, the full body will be read +// prior to the first request, and will be efficiently re-used for any retries. +// ReadSeeker can be used, but some users have observed occasional data races +// between the net/http library and the Seek functionality of some +// implementations of ReadSeeker, so should be avoided if possible. +package retryablehttp + +import ( + "bytes" + "fmt" + "io" + "io/ioutil" + "log" + "math" + "math/rand" + "net/http" + "net/url" + "os" + "strings" + "time" + + "github.com/hashicorp/go-cleanhttp" +) + +var ( + // Default retry configuration + defaultRetryWaitMin = 1 * time.Second + defaultRetryWaitMax = 30 * time.Second + defaultRetryMax = 4 + + // defaultClient is used for performing requests without explicitly making + // a new client. It is purposely private to avoid modifications. + defaultClient = NewClient() + + // We need to consume response bodies to maintain http connections, but + // limit the size we consume to respReadLimit. + respReadLimit = int64(4096) +) + +// ReaderFunc is the type of function that can be given natively to NewRequest +type ReaderFunc func() (io.Reader, error) + +// LenReader is an interface implemented by many in-memory io.Reader's. Used +// for automatically sending the right Content-Length header when possible. +type LenReader interface { + Len() int +} + +// Request wraps the metadata needed to create HTTP requests. +type Request struct { + // body is a seekable reader over the request body payload. This is + // used to rewind the request data in between retries. + body ReaderFunc + + // Embed an HTTP request directly. This makes a *Request act exactly + // like an *http.Request so that all meta methods are supported. + *http.Request +} + +// NewRequest creates a new wrapped request. +func NewRequest(method, url string, rawBody interface{}) (*Request, error) { + var err error + var body ReaderFunc + var contentLength int64 + + if rawBody != nil { + switch rawBody.(type) { + // If they gave us a function already, great! Use it. + case ReaderFunc: + body = rawBody.(ReaderFunc) + tmp, err := body() + if err != nil { + return nil, err + } + if lr, ok := tmp.(LenReader); ok { + contentLength = int64(lr.Len()) + } + if c, ok := tmp.(io.Closer); ok { + c.Close() + } + + case func() (io.Reader, error): + body = rawBody.(func() (io.Reader, error)) + tmp, err := body() + if err != nil { + return nil, err + } + if lr, ok := tmp.(LenReader); ok { + contentLength = int64(lr.Len()) + } + if c, ok := tmp.(io.Closer); ok { + c.Close() + } + + // If a regular byte slice, we can read it over and over via new + // readers + case []byte: + buf := rawBody.([]byte) + body = func() (io.Reader, error) { + return bytes.NewReader(buf), nil + } + contentLength = int64(len(buf)) + + // If a bytes.Buffer we can read the underlying byte slice over and + // over + case *bytes.Buffer: + buf := rawBody.(*bytes.Buffer) + body = func() (io.Reader, error) { + return bytes.NewReader(buf.Bytes()), nil + } + contentLength = int64(buf.Len()) + + // We prioritize *bytes.Reader here because we don't really want to + // deal with it seeking so want it to match here instead of the + // io.ReadSeeker case. + case *bytes.Reader: + buf, err := ioutil.ReadAll(rawBody.(*bytes.Reader)) + if err != nil { + return nil, err + } + body = func() (io.Reader, error) { + return bytes.NewReader(buf), nil + } + contentLength = int64(len(buf)) + + // Compat case + case io.ReadSeeker: + raw := rawBody.(io.ReadSeeker) + body = func() (io.Reader, error) { + raw.Seek(0, 0) + return ioutil.NopCloser(raw), nil + } + if lr, ok := raw.(LenReader); ok { + contentLength = int64(lr.Len()) + } + + // Read all in so we can reset + case io.Reader: + buf, err := ioutil.ReadAll(rawBody.(io.Reader)) + if err != nil { + return nil, err + } + body = func() (io.Reader, error) { + return bytes.NewReader(buf), nil + } + contentLength = int64(len(buf)) + + default: + return nil, fmt.Errorf("cannot handle type %T", rawBody) + } + } + + httpReq, err := http.NewRequest(method, url, nil) + if err != nil { + return nil, err + } + httpReq.ContentLength = contentLength + + return &Request{body, httpReq}, nil +} + +// RequestLogHook allows a function to run before each retry. The HTTP +// request which will be made, and the retry number (0 for the initial +// request) are available to users. The internal logger is exposed to +// consumers. +type RequestLogHook func(*log.Logger, *http.Request, int) + +// ResponseLogHook is like RequestLogHook, but allows running a function +// on each HTTP response. This function will be invoked at the end of +// every HTTP request executed, regardless of whether a subsequent retry +// needs to be performed or not. If the response body is read or closed +// from this method, this will affect the response returned from Do(). +type ResponseLogHook func(*log.Logger, *http.Response) + +// CheckRetry specifies a policy for handling retries. It is called +// following each request with the response and error values returned by +// the http.Client. If CheckRetry returns false, the Client stops retrying +// and returns the response to the caller. If CheckRetry returns an error, +// that error value is returned in lieu of the error from the request. The +// Client will close any response body when retrying, but if the retry is +// aborted it is up to the CheckResponse callback to properly close any +// response body before returning. +type CheckRetry func(resp *http.Response, err error) (bool, error) + +// Backoff specifies a policy for how long to wait between retries. +// It is called after a failing request to determine the amount of time +// that should pass before trying again. +type Backoff func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration + +// ErrorHandler is called if retries are expired, containing the last status +// from the http library. If not specified, default behavior for the library is +// to close the body and return an error indicating how many tries were +// attempted. If overriding this, be sure to close the body if needed. +type ErrorHandler func(resp *http.Response, err error, numTries int) (*http.Response, error) + +// Client is used to make HTTP requests. It adds additional functionality +// like automatic retries to tolerate minor outages. +type Client struct { + HTTPClient *http.Client // Internal HTTP client. + Logger *log.Logger // Customer logger instance. + + RetryWaitMin time.Duration // Minimum time to wait + RetryWaitMax time.Duration // Maximum time to wait + RetryMax int // Maximum number of retries + + // RequestLogHook allows a user-supplied function to be called + // before each retry. + RequestLogHook RequestLogHook + + // ResponseLogHook allows a user-supplied function to be called + // with the response from each HTTP request executed. + ResponseLogHook ResponseLogHook + + // CheckRetry specifies the policy for handling retries, and is called + // after each request. The default policy is DefaultRetryPolicy. + CheckRetry CheckRetry + + // Backoff specifies the policy for how long to wait between retries + Backoff Backoff + + // ErrorHandler specifies the custom error handler to use, if any + ErrorHandler ErrorHandler +} + +// NewClient creates a new Client with default settings. +func NewClient() *Client { + return &Client{ + HTTPClient: cleanhttp.DefaultClient(), + Logger: log.New(os.Stderr, "", log.LstdFlags), + RetryWaitMin: defaultRetryWaitMin, + RetryWaitMax: defaultRetryWaitMax, + RetryMax: defaultRetryMax, + CheckRetry: DefaultRetryPolicy, + Backoff: DefaultBackoff, + } +} + +// DefaultRetryPolicy provides a default callback for Client.CheckRetry, which +// will retry on connection errors and server errors. +func DefaultRetryPolicy(resp *http.Response, err error) (bool, error) { + if err != nil { + return true, err + } + // Check the response code. We retry on 500-range responses to allow + // the server time to recover, as 500's are typically not permanent + // errors and may relate to outages on the server side. This will catch + // invalid response codes as well, like 0 and 999. + if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != 501) { + return true, nil + } + + return false, nil +} + +// DefaultBackoff provides a default callback for Client.Backoff which +// will perform exponential backoff based on the attempt number and limited +// by the provided minimum and maximum durations. +func DefaultBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration { + mult := math.Pow(2, float64(attemptNum)) * float64(min) + sleep := time.Duration(mult) + if float64(sleep) != mult || sleep > max { + sleep = max + } + return sleep +} + +// LinearJitterBackoff provides a callback for Client.Backoff which will +// perform linear backoff based on the attempt number and with jitter to +// prevent a thundering herd. +// +// min and max here are *not* absolute values. The number to be multipled by +// the attempt number will be chosen at random from between them, thus they are +// bounding the jitter. +// +// For instance: +// * To get strictly linear backoff of one second increasing each retry, set +// both to one second (1s, 2s, 3s, 4s, ...) +// * To get a small amount of jitter centered around one second increasing each +// retry, set to around one second, such as a min of 800ms and max of 1200ms +// (892ms, 2102ms, 2945ms, 4312ms, ...) +// * To get extreme jitter, set to a very wide spread, such as a min of 100ms +// and a max of 20s (15382ms, 292ms, 51321ms, 35234ms, ...) +func LinearJitterBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration { + // attemptNum always starts at zero but we want to start at 1 for multiplication + attemptNum++ + + if max <= min { + // Unclear what to do here, or they are the same, so return min * + // attemptNum + return min * time.Duration(attemptNum) + } + + // Seed rand; doing this every time is fine + rand := rand.New(rand.NewSource(int64(time.Now().Nanosecond()))) + + // Pick a random number that lies somewhere between the min and max and + // multiply by the attemptNum. attemptNum starts at zero so we always + // increment here. We first get a random percentage, then apply that to the + // difference between min and max, and add to min. + jitter := rand.Float64() * float64(max-min) + jitterMin := int64(jitter) + int64(min) + return time.Duration(jitterMin * int64(attemptNum)) +} + +// PassthroughErrorHandler is an ErrorHandler that directly passes through the +// values from the net/http library for the final request. The body is not +// closed. +func PassthroughErrorHandler(resp *http.Response, err error, _ int) (*http.Response, error) { + return resp, err +} + +// Do wraps calling an HTTP method with retries. +func (c *Client) Do(req *Request) (*http.Response, error) { + if c.Logger != nil { + c.Logger.Printf("[DEBUG] %s %s", req.Method, req.URL) + } + + var resp *http.Response + var err error + + for i := 0; ; i++ { + var code int // HTTP response code + + // Always rewind the request body when non-nil. + if req.body != nil { + body, err := req.body() + if err != nil { + return resp, err + } + if c, ok := body.(io.ReadCloser); ok { + req.Request.Body = c + } else { + req.Request.Body = ioutil.NopCloser(body) + } + } + + if c.RequestLogHook != nil { + c.RequestLogHook(c.Logger, req.Request, i) + } + + // Attempt the request + resp, err = c.HTTPClient.Do(req.Request) + if resp != nil { + code = resp.StatusCode + } + + // Check if we should continue with retries. + checkOK, checkErr := c.CheckRetry(resp, err) + + if err != nil { + if c.Logger != nil { + c.Logger.Printf("[ERR] %s %s request failed: %v", req.Method, req.URL, err) + } + } else { + // Call this here to maintain the behavior of logging all requests, + // even if CheckRetry signals to stop. + if c.ResponseLogHook != nil { + // Call the response logger function if provided. + c.ResponseLogHook(c.Logger, resp) + } + } + + // Now decide if we should continue. + if !checkOK { + if checkErr != nil { + err = checkErr + } + return resp, err + } + + // We do this before drainBody beause there's no need for the I/O if + // we're breaking out + remain := c.RetryMax - i + if remain <= 0 { + break + } + + // We're going to retry, consume any response to reuse the connection. + if err == nil && resp != nil { + c.drainBody(resp.Body) + } + + wait := c.Backoff(c.RetryWaitMin, c.RetryWaitMax, i, resp) + desc := fmt.Sprintf("%s %s", req.Method, req.URL) + if code > 0 { + desc = fmt.Sprintf("%s (status: %d)", desc, code) + } + if c.Logger != nil { + c.Logger.Printf("[DEBUG] %s: retrying in %s (%d left)", desc, wait, remain) + } + time.Sleep(wait) + } + + if c.ErrorHandler != nil { + return c.ErrorHandler(resp, err, c.RetryMax+1) + } + + // By default, we close the response body and return an error without + // returning the response + if resp != nil { + resp.Body.Close() + } + return nil, fmt.Errorf("%s %s giving up after %d attempts", + req.Method, req.URL, c.RetryMax+1) +} + +// Try to read the response body so we can reuse this connection. +func (c *Client) drainBody(body io.ReadCloser) { + defer body.Close() + _, err := io.Copy(ioutil.Discard, io.LimitReader(body, respReadLimit)) + if err != nil { + if c.Logger != nil { + c.Logger.Printf("[ERR] error reading response body: %v", err) + } + } +} + +// Get is a shortcut for doing a GET request without making a new client. +func Get(url string) (*http.Response, error) { + return defaultClient.Get(url) +} + +// Get is a convenience helper for doing simple GET requests. +func (c *Client) Get(url string) (*http.Response, error) { + req, err := NewRequest("GET", url, nil) + if err != nil { + return nil, err + } + return c.Do(req) +} + +// Head is a shortcut for doing a HEAD request without making a new client. +func Head(url string) (*http.Response, error) { + return defaultClient.Head(url) +} + +// Head is a convenience method for doing simple HEAD requests. +func (c *Client) Head(url string) (*http.Response, error) { + req, err := NewRequest("HEAD", url, nil) + if err != nil { + return nil, err + } + return c.Do(req) +} + +// Post is a shortcut for doing a POST request without making a new client. +func Post(url, bodyType string, body interface{}) (*http.Response, error) { + return defaultClient.Post(url, bodyType, body) +} + +// Post is a convenience method for doing simple POST requests. +func (c *Client) Post(url, bodyType string, body interface{}) (*http.Response, error) { + req, err := NewRequest("POST", url, body) + if err != nil { + return nil, err + } + req.Header.Set("Content-Type", bodyType) + return c.Do(req) +} + +// PostForm is a shortcut to perform a POST with form data without creating +// a new client. +func PostForm(url string, data url.Values) (*http.Response, error) { + return defaultClient.PostForm(url, data) +} + +// PostForm is a convenience method for doing simple POST operations using +// pre-filled url.Values form data. +func (c *Client) PostForm(url string, data url.Values) (*http.Response, error) { + return c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode())) +} |