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https://github.com/kemko/nomad.git
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d28af58cbb
First of all, we should not send the unix time, but the monotonic time. Second of all, RELOADING= and MONOTONIC_USEC fields should be sent in *single* message not two separate messages. From the man page of [systemd.service](https://www.freedesktop.org/software/systemd/man/latest/systemd.service.html#Type=) > notification message via sd_notify(3) that contains the "RELOADING=1" field in > combination with "MONOTONIC_USEC=" set to the current monotonic time (i.e. > CLOCK_MONOTONIC in clock_gettime(2)) in μs, formatted as decimal string. [sd_notify](https://www.freedesktop.org/software/systemd/man/latest/sd_notify.html) now has code samples of the protocol to clarify. Without these changes, if you'd set Type=notify-reload on the agen'ts systemd unit, systemd would kill the service due to the service not responding to reload correctly.
50 lines
1.2 KiB
Go
50 lines
1.2 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: BUSL-1.1
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//go:build linux
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package agent
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import (
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"fmt"
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"io"
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"net"
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"os"
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"time"
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"golang.org/x/sys/unix"
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)
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const sdNotifySocketEnvVar = "NOTIFY_SOCKET"
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// openNotify opens the systemd notify socket only if the expected env var has
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// been set, because the systemd unit file is Type=notify or Type=notify-reload
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// (systemd 253+). It then unsets the env var in the agent process so that child
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// processes can't accidentally inherit it. This function returns (nil, nil) if
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// the env var isn't set.
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func openNotify() (io.WriteCloser, error) {
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socketPath := os.Getenv(sdNotifySocketEnvVar)
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if socketPath == "" {
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return nil, nil
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}
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defer os.Unsetenv(sdNotifySocketEnvVar)
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conn, err := net.DialTimeout("unixgram", socketPath, time.Second)
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return conn, err
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}
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// sdNotify sends the message on the systemd notify socket, and gracefully
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// handles a nil socket
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func sdNotify(w io.Writer, msg string) {
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if w == nil || msg == "" {
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return
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}
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w.Write([]byte(msg))
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}
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func sdNotifyReloading(w io.Writer) {
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var ts unix.Timespec
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unix.ClockGettime(unix.CLOCK_MONOTONIC, &ts)
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sdNotify(w, fmt.Sprintf("RELOADING=1\nMONOTONIC_USEC=%d", ts.Nano()/1000))
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}
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