98 lines
3.5 KiB
Diff
98 lines
3.5 KiB
Diff
From 3babc7a5b767fb60ca877213d9201568205e983f Mon Sep 17 00:00:00 2001
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From: Jonathan Lebon <jonathan@jlebon.com>
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Date: Thu, 8 Feb 2024 11:02:27 -0500
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Subject: [PATCH] azure: retry HTTP requests on codes 404, 410, and 429
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For some reason, the Azure IMDS server expects clients to retry their
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HTTP requests even on codes that usually would be considered final.
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The documented one is 410[[1]], but let's just match the set from
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cloud-init, which also includes 404 and 429[[2]].
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Closes: #1806
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[1]: https://learn.microsoft.com/en-us/azure/virtual-machines/instance-metadata-service?tabs=linux#errors-and-debugging
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[2]: https://github.com/canonical/cloud-init/commit/c1a2047cf291
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travier: Edited to cleanly backport on top of 2.17.0
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---
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internal/providers/azure/azure.go | 11 ++++++++++-
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internal/resource/http.go | 17 ++++++++++++++++-
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internal/resource/url.go | 4 ++++
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3 files changed, 30 insertions(+), 2 deletions(-)
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diff --git a/internal/providers/azure/azure.go b/internal/providers/azure/azure.go
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index d3115f2b..caddcff5 100644
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--- a/internal/providers/azure/azure.go
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+++ b/internal/providers/azure/azure.go
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@@ -112,7 +112,16 @@ func fetchFromIMDS(f *resource.Fetcher) ([]byte, error) {
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headers := make(http.Header)
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headers.Set("Metadata", "true")
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- data, err := f.FetchToBuffer(imdsUserdataURL, resource.FetchOptions{Headers: headers})
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+ // Azure IMDS expects some codes <500 to still be retried...
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+ // Here, we match the cloud-init set.
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+ // https://github.com/canonical/cloud-init/commit/c1a2047cf291
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+ // https://github.com/coreos/ignition/issues/1806
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+ retryCodes := []int{
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+ 404, // not found
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+ 410, // gone
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+ 429, // rate-limited
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+ }
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+ data, err := f.FetchToBuffer(imdsUserdataURL, resource.FetchOptions{Headers: headers, RetryCodes: retryCodes})
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if err != nil {
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return nil, fmt.Errorf("fetching to buffer: %w", err)
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}
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diff --git a/internal/resource/http.go b/internal/resource/http.go
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index 0d8edace..872ce253 100644
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--- a/internal/resource/http.go
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+++ b/internal/resource/http.go
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@@ -263,6 +263,21 @@ func (f *Fetcher) newHttpClient() error {
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return nil
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}
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+func shouldRetryHttp(statusCode int, opts FetchOptions) bool {
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+ // we always retry 500+
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+ if statusCode >= 500 {
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+ return true
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+ }
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+
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+ for _, retryCode := range opts.RetryCodes {
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+ if statusCode == retryCode {
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+ return true
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+ }
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+ }
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+
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+ return false
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+}
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+
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// httpReaderWithHeader performs an HTTP request on the provided URL with the
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// provided request header & method and returns the response body Reader, HTTP
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// status code, a cancel function for the result's context, and error (if any).
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@@ -298,7 +313,7 @@ func (c HttpClient) httpReaderWithHeader(opts FetchOptions, url string) (io.Read
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if err == nil {
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c.logger.Info("%s result: %s", opts.HTTPVerb, http.StatusText(resp.StatusCode))
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- if resp.StatusCode < 500 {
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+ if !shouldRetryHttp(resp.StatusCode, opts) {
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return resp.Body, resp.StatusCode, cancelFn, nil
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}
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resp.Body.Close()
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diff --git a/internal/resource/url.go b/internal/resource/url.go
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index 58e0b9fc..3d16cc59 100644
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--- a/internal/resource/url.go
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+++ b/internal/resource/url.go
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@@ -125,6 +125,10 @@ type FetchOptions struct {
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// HTTPVerb is an HTTP request method to indicate the desired action to
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// be performed for a given resource.
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HTTPVerb string
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+
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+ // List of HTTP codes to retry that usually would be considered as complete.
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+ // Status codes >= 500 are always retried.
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+ RetryCodes []int
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}
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// FetchToBuffer will fetch the given url into a temporary file, and then read
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--
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2.43.0
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