feat: add h2c (HTTP/2 cleartext) support#182
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PhilipSchmid merged 1 commit intomainfrom Apr 8, 2026
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Add --h2c flag and ECHO_APP_H2C env var that wraps the plain HTTP listener with h2c.NewHandler(), enabling HTTP/2 cleartext on the existing HTTP port without requiring a separate listener. - Add H2C bool field to Config struct with viper wiring - Add --h2c pflag in main.go - Promote golang.org/x/net to a direct dependency - Wrap handler with h2c.NewHandler() when cfg.H2C is true - Add TestH2CServer_HTTP2Negotiation to verify ProtoMajor == 2 - Document ECHO_APP_H2C and --h2c in README.md Closes #181 Signed-off-by: Philip Schmid <phisch@cisco.com>
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Summary
Adds HTTP/2 cleartext (h2c) support to the plain HTTP listener via a new
--h2cflag /ECHO_APP_H2Cenvironment variable.When enabled, the HTTP listener is wrapped with
h2c.NewHandler()fromgolang.org/x/net/http2/h2c, allowing it to accept both HTTP/1.1 and HTTP/2 cleartext connections on the same port — no separate listener or TLS required.This is needed for backends behind a Gateway API proxy that uses
appProtocol: kubernetes.io/h2cfor upstream HTTP/2 (e.g. Cilium Gateway API withgatewayAPI.enableAppProtocol).Changes
internal/config/config.go: addH2C boolfield, default, and viper bindingcmd/echo-app/main.go: add--h2cpflaginternal/server/http_server.go: wrap handler withh2c.NewHandler()whencfg.H2Cis truego.mod: promotegolang.org/x/netfrom indirect to direct dependencyinternal/server/http_server_test.go: addTestH2CServer_HTTP2Negotiation— starts an h2c server and verifiesresp.ProtoMajor == 2using anhttp2.TransportwithAllowHTTP: trueREADME.md: documentECHO_APP_H2Cenv var and--h2cflagCloses #181