commit b970ea1c866f05b37be90b2a22f972d441e78f83 Author: Balakrishnan Balasubramanian Date: Thu Apr 20 16:31:35 2023 -0400 initial version diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..ad2653a --- /dev/null +++ b/LICENSE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright 2022 balki + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/README.md b/README.md new file mode 100644 index 0000000..2eae9dd --- /dev/null +++ b/README.md @@ -0,0 +1,51 @@ +Create http server listening on unix sockets or systemd socket activated fds + +## Quick Usage + +Just replace `http.ListenAndServe` with `anyhttp.ListenAndServe`. + +```diff +- http.ListenAndServe(addr, h) ++ anyhttp.ListenAndServe(addr, h) +``` + +### Address Syntax + +#### Unix socket + +Syntax + + unix/ + +Examples + + unix/relative/path.sock + unix//var/run/app/absolutepath.sock + +#### Systemd Socket activated fd: + +Syntax + + sysd/fdidx/ + sysd/fdname/ + +Examples: + + # First (or only) socket fd passed to app + sysd/fdidx/0 + + # Socket with FileDescriptorName + sysd/fdname/myapp + + # Using default name + sysd/fdname/myapp.socket + +#### TCP port + +If the address is a number less than 65536, it is assumed as a port and passed as `http.ListenAndServe(":",...)` + +Anything else is directly passed to `http.ListenAndServe` as well. Below examples should work + + :http + :8888 + 127.0.0.1:8080 diff --git a/anyhttp.go b/anyhttp.go new file mode 100644 index 0000000..12150cc --- /dev/null +++ b/anyhttp.go @@ -0,0 +1,188 @@ +// Package anyhttp has helpers to serve http from unix sockets and systemd socket activated fds +package anyhttp + +import ( + "errors" + "fmt" + "io/fs" + "net" + "net/http" + "os" + "strconv" + "strings" + "syscall" +) + +type UnixSocketConfig struct { + SocketPath string + SocketMode fs.FileMode + RemoveExisting bool +} + +var DefaultUnixSocketConfig = UnixSocketConfig{ + SocketMode: 0666, + RemoveExisting: true, +} + +func NewUnixSocketConfig(socketPath string) UnixSocketConfig { + usc := DefaultUnixSocketConfig + usc.SocketPath = socketPath + return usc +} + +type SysdConfig struct { + FDIndex *int + FDName *string + CheckPID bool + UnsetEnv bool +} + +var DefaultSysdConfig = SysdConfig{ + CheckPID: true, + UnsetEnv: false, +} + +func NewSysDConfigWithFDIdx(fdIdx int) SysdConfig { + sysc := DefaultSysdConfig + sysc.FDIndex = &fdIdx + return sysc +} + +func NewSysDConfigWithFDName(fdName string) SysdConfig { + sysc := DefaultSysdConfig + sysc.FDName = &fdName + return sysc +} + +func (u *UnixSocketConfig) GetListener() (net.Listener, error) { + + if u.RemoveExisting { + if err := os.Remove(u.SocketPath); err != nil && !errors.Is(err, fs.ErrNotExist) { + return nil, err + } + } + + l, err := net.Listen("unix", u.SocketPath) + if err != nil { + return nil, err + } + + if err = os.Chmod(u.SocketPath, u.SocketMode); err != nil { + return nil, err + } + + return l, nil +} + +const StartFD = 3 + +func makeFdListener(fd int, name string) (net.Listener, error) { + fdFile := os.NewFile(uintptr(fd), name) + l, err := net.FileListener(fdFile) + if err != nil { + return nil, err + } + syscall.CloseOnExec(fd) + return l, nil +} + +func (s *SysdConfig) GetListener() (net.Listener, error) { + + if s.UnsetEnv { + defer UnsetSystemdListenVars() + } + + if s.CheckPID { + pid, err := strconv.Atoi(os.Getenv("LISTEN_PID")) + if err != nil { + return nil, err + } + if pid != os.Getpid() { + return nil, fmt.Errorf("fd not for you") + } + } + + numFds, err := strconv.Atoi(os.Getenv("LISTEN_FDS")) + if err != nil { + return nil, err + } + + fdNames := strings.Split(os.Getenv("LISTEN_FDNAMES"), ":") + + if s.FDIndex != nil { + idx := *s.FDIndex + if idx < 0 || idx >= numFds { + return nil, fmt.Errorf("invalid fd") + } + fd := StartFD + idx + if idx < len(fdNames) { + return makeFdListener(fd, fdNames[idx]) + } else { + return makeFdListener(fd, fmt.Sprintf("sysdfd_%d", fd)) + } + } + + if s.FDName != nil { + for idx, name := range fdNames { + if name == *s.FDName { + fd := StartFD + idx + return makeFdListener(fd, name) + } + } + return nil, fmt.Errorf("fdName not found: %q", *s.FDName) + } + + return nil, fmt.Errorf("neither FDIndex nor FDName set") +} + +// GetListener gets a unix or systemd socket listener +func GetListener(addr string) (net.Listener, error) { + if strings.HasPrefix(addr, "unix/") { + usc := NewUnixSocketConfig(strings.TrimPrefix(addr, "unix/")) + return usc.GetListener() + } + + if strings.HasPrefix(addr, "sysd/fdidx/") { + idx, err := strconv.Atoi(strings.TrimPrefix(addr, "sysd/fdidx/")) + if err != nil { + return nil, err + } + sysdc := NewSysDConfigWithFDIdx(idx) + return sysdc.GetListener() + } + + if strings.HasPrefix(addr, "sysd/fdname/") { + sysdc := NewSysDConfigWithFDName(strings.TrimPrefix(addr, "sysd/fdname/")) + return sysdc.GetListener() + } + + return nil, nil +} + +func ListenAndServe(addr string, h http.Handler) error { + + listener, err := GetListener(addr) + if err != nil { + return err + } + + if listener != nil { + return http.Serve(listener, h) + } + + if port, err := strconv.Atoi(addr); err == nil { + if port > 0 && port < 65536 { + + return http.ListenAndServe(fmt.Sprintf(":%v", port), h) + } + return fmt.Errorf("invalid port: %v", port) + } + + return http.ListenAndServe(addr, h) +} + +func UnsetSystemdListenVars() { + os.Unsetenv("LISTEN_PID") + os.Unsetenv("LISTEN_FDS") + os.Unsetenv("LISTEN_FDNAMES") +} diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..783c742 --- /dev/null +++ b/go.mod @@ -0,0 +1,3 @@ +module go.balki.me/anyhttp + +go 1.20