Image build timestamp inconsistency

[marian-pritsak]

Description

Image timestamp in show version is different from /host directory:

show version
SONiC Software Version: SONiC.201807.0-dirty-20180925.144022
Distribution: Debian 9.5
Kernel: 4.9.0-7-amd64
Build commit: cfe01f1
Build date: Tue Sep 25 14:40:22 UTC 2018
Built by: marianp@arc-build-server

Docker images:
REPOSITORY TAG IMAGE ID SIZE
docker-fpm-quagga 201807.0-dirty-20180925.144152 536a8c5d1e00 265.5 MB
docker-fpm-quagga latest 536a8c5d1e00 265.5 MB
docker-orchagent-mlnx 201807.0-dirty-20180925.144335 55a7fd731d51 260.7 MB
docker-orchagent-mlnx latest 55a7fd731d51 260.7 MB
docker-teamd 201807.0-dirty-20180925.144239 e47f7d2f9db9 258.7 MB
docker-teamd latest e47f7d2f9db9 258.7 MB
docker-snmp-sv2 201807.0-dirty-20180925.144228 3cbfa46c414d 291.2 MB
docker-snmp-sv2 latest 3cbfa46c414d 291.2 MB
docker-lldp-sv2 201807.0-dirty-20180925.144309 dc512d17d5f9 272 MB
docker-lldp-sv2 latest dc512d17d5f9 272 MB
docker-platform-monitor 201807.0-dirty-20180925.144204 890797d9aa87 283.4 MB
docker-platform-monitor latest 890797d9aa87 283.4 MB
docker-syncd-mlnx 201807.0-dirty-20180925.144327 8e4b54f86670 360.7 MB
docker-syncd-mlnx latest 8e4b54f86670 360.7 MB
docker-database 201807.0-dirty-20180925.144250 d3681404e4b4 252.4 MB
docker-database latest d3681404e4b4 252.4 MB
docker-dhcp-relay 201807.0-dirty-20180925.144300 0660bb644274 253.7 MB
docker-dhcp-relay latest 0660bb644274 253.7 MB
docker-router-advertiser 201807.0-dirty-20180925.144215 3d4efc9d477a 250 MB
docker-router-advertiser latest 3d4efc9d477a 250 MB

ls /host/
disk-img grub image-201807.0-dirty-20180925.144644 lost+found machine.conf

Steps to reproduce the issue:

Describe the results you received:
Image under /host has different timestamp in a name from image version, and rc.local cannot find firsttime file, resulting in initialization sequence failure

Describe the results you expected:
Image directory under /host should have the same timestamp in a name as image version

Additional information you deem important (e.g. issue happens only occasionally):

**Output of `show version`:**

SONiC Software Version: SONiC.201807.0-dirty-20180925.**144022**
Distribution: Debian 9.5
Kernel: 4.9.0-7-amd64
Build commit: cfe01f1
Build date: Tue Sep 25 14:40:22 UTC 2018
Built by: marianp@arc-build-server

Docker images:
REPOSITORY                 TAG                              IMAGE ID            SIZE
docker-fpm-quagga          201807.0-dirty-20180925.144152   536a8c5d1e00        265.5 MB
docker-fpm-quagga          latest                           536a8c5d1e00        265.5 MB
docker-orchagent-mlnx      201807.0-dirty-20180925.144335   55a7fd731d51        260.7 MB
docker-orchagent-mlnx      latest                           55a7fd731d51        260.7 MB
docker-teamd               201807.0-dirty-20180925.144239   e47f7d2f9db9        258.7 MB
docker-teamd               latest                           e47f7d2f9db9        258.7 MB
docker-snmp-sv2            201807.0-dirty-20180925.144228   3cbfa46c414d        291.2 MB
docker-snmp-sv2            latest                           3cbfa46c414d        291.2 MB
docker-lldp-sv2            201807.0-dirty-20180925.144309   dc512d17d5f9        272 MB
docker-lldp-sv2            latest                           dc512d17d5f9        272 MB
docker-platform-monitor    201807.0-dirty-20180925.144204   890797d9aa87        283.4 MB
docker-platform-monitor    latest                           890797d9aa87        283.4 MB
docker-syncd-mlnx          201807.0-dirty-20180925.144327   8e4b54f86670        360.7 MB
docker-syncd-mlnx          latest                           8e4b54f86670        360.7 MB
docker-database            201807.0-dirty-20180925.144250   d3681404e4b4        252.4 MB
docker-database            latest                           d3681404e4b4        252.4 MB
docker-dhcp-relay          201807.0-dirty-20180925.144300   0660bb644274        253.7 MB
docker-dhcp-relay          latest                           0660bb644274        253.7 MB
docker-router-advertiser   201807.0-dirty-20180925.144215   3d4efc9d477a        250 MB
docker-router-advertiser   latest                           3d4efc9d477a        250 MB

[marian-pritsak]

Suggest to cache date in a temporary file upon first call of https://github.com/Azure/sonic-buildimage/blob/0e85986088a97135dc4472d49c1f2fa8bc264318/functions.sh#L53 so that function will always return same value

[fillmorechen0928]

This issue cause the firsttime file could not be found.

[lguohan]

@jipanyang , looks like introduce in this PR. https://github.com/Azure/sonic-buildimage/pull/2058/files

Can you fix?

[jipanyang]

Working on the fix.

[lguohan]

addressed in #2108