From cc7991d97715ab6ad19da54476a0c633e7bc1880 Mon Sep 17 00:00:00 2001 From: Tomas Dohnalek Date: Wed, 13 Apr 2022 07:21:50 +0200 Subject: [PATCH] Make Query requests idempotent (#1022) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * Make Query requests idempotent Address #1020. Signed-off-by: Tomáš Dohnálek * Use empty header Signed-off-by: Tomáš Dohnálek * Document issue with original documentation Signed-off-by: Tomáš Dohnálek --- api/prometheus/v1/api.go | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/api/prometheus/v1/api.go b/api/prometheus/v1/api.go index 0be68fa..5ed0912 100644 --- a/api/prometheus/v1/api.go +++ b/api/prometheus/v1/api.go @@ -1139,6 +1139,14 @@ func (h *apiClientImpl) DoGetFallback(ctx context.Context, u *url.URL, args url. return nil, nil, nil, err } req.Header.Set("Content-Type", "application/x-www-form-urlencoded") + // Following comment originates from https://pkg.go.dev/net/http#Transport + // Transport only retries a request upon encountering a network error if the request is + // idempotent and either has no body or has its Request.GetBody defined. HTTP requests + // are considered idempotent if they have HTTP methods GET, HEAD, OPTIONS, or TRACE; or + // if their Header map contains an "Idempotency-Key" or "X-Idempotency-Key" entry. If the + // idempotency key value is a zero-length slice, the request is treated as idempotent but + // the header is not sent on the wire. + req.Header["Idempotency-Key"] = nil resp, body, warnings, err := h.Do(ctx, req) if resp != nil && (resp.StatusCode == http.StatusMethodNotAllowed || resp.StatusCode == http.StatusNotImplemented) {