From 3601b96600807214d74b9c77c614fa03bfae30a8 Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Sun, 28 Jun 2020 11:06:46 -0400 Subject: Allow empty host port in --publish flag I didn't believe that this was actually legal, but it looks like it is. And, unlike our previous understanding (host port being empty means just use container port), empty host port actually carries the same meaning as `--expose` + `--publish-all` (that is, assign a random host port to the given container port). This requires a significant rework of our port handling code to handle this new case. I don't foresee this being commonly used, so I optimized having a fixed port number as fast path, which this random assignment code running after the main port handling code only if necessary. Fixes #6806 Signed-off-by: Matthew Heon --- cmd/podman/common/util.go | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) (limited to 'cmd') diff --git a/cmd/podman/common/util.go b/cmd/podman/common/util.go index ce323a4ba..6c8c22147 100644 --- a/cmd/podman/common/util.go +++ b/cmd/podman/common/util.go @@ -184,22 +184,24 @@ func parseSplitPort(hostIP, hostPort *string, ctrPort string, protocol *string) } if hostPort != nil { if *hostPort == "" { - return newPort, errors.Errorf("must provide a non-empty container host port to publish") - } - hostStart, hostLen, err := parseAndValidateRange(*hostPort) - if err != nil { - return newPort, errors.Wrapf(err, "error parsing host port") - } - if hostLen != ctrLen { - return newPort, errors.Errorf("host and container port ranges have different lengths: %d vs %d", hostLen, ctrLen) + // Set 0 as a placeholder. The server side of Specgen + // will find a random, open, unused port to use. + newPort.HostPort = 0 + } else { + hostStart, hostLen, err := parseAndValidateRange(*hostPort) + if err != nil { + return newPort, errors.Wrapf(err, "error parsing host port") + } + if hostLen != ctrLen { + return newPort, errors.Errorf("host and container port ranges have different lengths: %d vs %d", hostLen, ctrLen) + } + newPort.HostPort = hostStart } - newPort.HostPort = hostStart + } else { + newPort.HostPort = newPort.ContainerPort } hport := newPort.HostPort - if hport == 0 { - hport = newPort.ContainerPort - } logrus.Debugf("Adding port mapping from %d to %d length %d protocol %q", hport, newPort.ContainerPort, newPort.Range, newPort.Protocol) return newPort, nil -- cgit v1.2.3-54-g00ecf