Function getPortMappingsOnMac

dgraphtest/dgraph.go:428–456

getPortMappingsOnMac parses `docker ps` output to get accurate macOS mappings because docker inspect does not know about port mappings at all.

(containerID, privatePort string)

// getPortMappingsOnMac parses `docker ps` output to get accurate macOS mappings
// because docker inspect does not know about port mappings at all.
func getPortMappingsOnMac(containerID, privatePort string) (string, error) {
	out, err := exec.Command("docker", "ps", "--format", "{{.ID}} {{.Ports}}").Output()
	if err != nil {
		return "", fmt.Errorf("docker ps failed: %w", err)
	}

	for line := range strings.SplitSeq(string(out), "\n") {
		fields := strings.Fields(line)
		if len(fields) < 2 || !strings.HasPrefix(containerID, fields[0]) {
			continue
		}

		// Example: "0.0.0.0:55069->8080/tcp," => "55069"
		for _, part := range fields[1:] {
			if strings.Contains(part, privatePort+"/tcp") {
				// A port entry like "8080/tcp" has no colon because the port
				// wasn't published to the host; skip it rather than panic on
				// an out-of-range index.
				colonParts := strings.Split(part, ":")
				if len(colonParts) < 2 {
					continue
				}
				return strings.Split(colonParts[1], "->")[0], nil
			}
		}
	}

	return "", fmt.Errorf("no mapping found for private port [%v] for container [%v]", privatePort, containerID)
}

func mountBinary(c *LocalCluster) (mount.Mount, error) {
	// We shouldn't need to call setupBinary here, we already call it in LocalCluster.setupBeforeCluster