where is the code about objects mapping?

The strategies and background is subtle, but you could find the codes in: L416~L427

https://github.com/openstack/swift/blob/master/swift/obj/diskfile.py#L416

It's now whole, but an enough hint for you

If you're interested in the theory about this, try to read this blog: http://julien.danjou.info/blog/2012/openstack-swift-consistency-analysis

or swiftstack‘s book http://swiftstack.com/book/

Thanks, Kun Huang.
When I input "account:user, container, object", I want to get the address of one of the replicas in swift.
Such as when I input "test:tester, container_test1, ppt.pdf", I hope to get "/mnt/sdb1/1/node/sdb1/objects/497/382/7c5f513fe9483ed4d2646c059a79d382/1383891714.41626.data".
If there is a method without modifying the source code of swift, could you tell me how can I do that? It is perfect to obtain the address without modifying the source code.
If it is essential to modify the source code to get the address, could you give me some advices?

It's easy, and you don't need change source codes. Just try "swift-get-codes", following its help message and you could find physical address of an object, a container or an account.

Thanks, Kun Huang.
As an Administrator, I want to have an interface to obtain the physical address of an object.
 Perhaps I need many objects addresses on time.

I want to achieve such a function that objects not being accessed for a long long time move from swift to other places. So I need to obtain the physical address of an object easy and fast. And it is better not disturbing the running swift. It is perfect to obtain the address without modifying the source code.

I think that your above advices can help me. Could you explain it with more details?

Thanks, , Kun Huang. You are so kind.
 But when I have a try, I meet this
swift@qwn-G31M-S2C:~$ swift-get-nodes -a /etc/swift/account.ring.gz test
Traceback (most recent call last):
  File "/usr/local/bin/swift-get-nodes", line 7, in <module>
    execfile(__file__)
  File "/home/swift/swift/bin/swift-get-nodes", line 22, in <module>
    from swift.common.utils import hash_path
ImportError: cannot import name hash_path

I installed swift SAIO, and its version is swift 1.6.0.1

I find this is a bug. And Swift 1.10.0 has resolved it.

Can I upgrade my swift SAIO instead of re install it?

If this is the first time you try swift, please use the newest codes. That error seems a very old bug.

Thanks, , Kun Huang. You are so kind. Your advices almost resolve my problems.
But there is one thing left. I want to get the object's full path, including the last "******.data".
"swift-get-nodes" method tells me the path, not including the object's *.data file name.

Such as when I used "swift-get-nodes", I got "/mnt/sdb1/1/node/sdb1/objects/497/382/7c5f513fe9483ed4d2646c059a79d382/". But I also need the last "1383891714.41626.data". I hope I can get "/mnt/sdb1/1/node/sdb1/objects/497/382/7c5f513fe9483ed4d2646c059a79d382/1383891714.41626.data"

Thank you very much.

swift@cloud1:~$ swift -A http://127.0.0.1:8080/auth/v1.0 -U test:tester -K testing list test1
cert.key
proxy-server.conf
swift@cloud1:~$ swift-get-nodes -a /etc/swift/object.ring.gz test test1 cert.key

Account test
Container test1
Object cert.key

Partition 34233
Hash 216e50dc72887cf0c7982b0edd5b63b6

Server:Port Device 192.168.1.3:6010 sdb1
Server:Port Device 192.168.1.5:6010 sdb1
Server:Port Device 192.168.1.4:6010 sdb1

curl -I -XHEAD "http://192.168.1.3:6010/sdb1/34233/test/test1/cert.key"
curl -I -XHEAD "http://192.168.1.5:6010/sdb1/34233/test/test1/cert.key"
curl -I -XHEAD "http://192.168.1.4:6010/sdb1/34233/test/test1/cert.key"

Use your own device location of servers:
such as "export DEVICE=/srv/node"
ssh 192.168.1.3 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/34233/3b6/216e50dc72887cf0c7982b0edd5b63b6/"
ssh 192.168.1.5 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/34233/3b6/216e50dc72887cf0c7982b0edd5b63b6/"
ssh 192.168.1.4 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/34233/3b6/216e50dc72887cf0c7982b0edd5b63b6/"
swift@cloud1:~$

See the last part of your output, and you can find that is ssh command:

ssh <address> "<command>"

That is used to run <command> in target address. And what is output of ls? That is what you need now.

So try paste&copy and run that ssh command: )

I meet another strange problem.

I use ssh to connect 192.168.1.3. And I can find the path "/srv/node/sdb1/objects". But I can not find the path /srv/node/sdb1/objects/34233. There is no such a path named 34233.

It is really confused me.

swift@cloud1:~$ ssh 192.168.1.3 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/34233/3b6/216e50dc72887cf0c7982b0edd5b63b6/"

swift@192.168.1.3's password:
ls: 初始化月份字符串出错
ls: 无法访问/srv/node/sdb1/objects/34233/3b6/216e50dc72887cf0c7982b0edd5b63b6/: 没有那个文件或目录

notice this:

Use your own device location of servers:
such as "export DEVICE=/srv/node"

If you installed your cluster by SAIO document, I think you should export your own environment variable DEVICE by your own config files.

Thanks, Kun Huang.
I used both swift installed in 4 DELL servers and Swift SAIO for testing.
I can upload and download.
but when I used "swift-get-nodes", the Partition returned is not a folder in the storage node.

my DEVICE is set "/srv/node". There are many folders in “/srv/node/sdb1/objects/”, but there is not a folder named "61178". What's wrong?

There are some output of swift in 4 DELL servers, not of SAIO.

103748 126837 149607 173774 199160 224454 245960 35322 59406 81540
103759 126936 150199 173928 199274 224706 246115 35640 59883 81645
104006 127348 150388 174134 199316 224827 246328 35849 60625 82238
104023 127379 150421 174314 199607 22492 246504 35853 61046 8236
104036 12739 150443 174445 199656 224949 247236 3593 61104 82599
104155 127440 150555 174603 199993 22504 247474 36058 61285 829
104330 127876 150775 174775 200217 225222 248137 36533 61321 82982
104503 1279 151115 174919 200408 225251 249085 36593 6133 8299
10460 127971 152044 174941 200664 225523 249204 36968 61354 83013
104800 12821 152185 174971 200776 225548 249277 3722 61411 83035
104976 128482 152222 175017 201129 225639 249300 37808 61812 83806
104999 128577 152835 175140 201141 22576 24942 38130 62058 83874
105016 128778 153060 175340 201340 225873 249644 38514 62190 83956
105082 128972 153126 175360 201619 225888 249910 38592 62233 84005
105114 129266 153247 175482 201692 226246 249933 38613 62235 84290
105560 129368 153340 175781 201952 226464 250062 38616 62547 84448
105587 129420 153406 175810 202096 226583 2502 38885 62577 84471
105712 129613 153427 176219 202921 226675 250392 3896 62667 8464
105918 129644 153446 176406 203144 226927 250484 38968 62739 84936

swift@cloud1:~/openstack$ swift -A http://127.0.0.1:8080/auth/v1.0 -U test:tester -K testing list cont1
boto-2.6.0.tar.gz
swift@cloud1:~/openstack$ cd
swift@cloud1:~$ swift-get-nodes -a /etc/swift/object.ring.gz test cont1 boto-2.6.0.tar.gz

Account test
Container cont1
Object boto-2.6.0.tar.gz

Partition 61178
Hash 3bbe955693bec810b7cfa75b9e8eb1af

Server:Port Device 192.168.1.4:6010 sdb1
Server:Port Device 192.168.1.3:6010 sdb1
Server:Port Device 192.168.1.5:6010 sdb1

curl -I -XHEAD "http://192.168.1.4:6010/sdb1/61178/test/cont1/boto-2.6.0.tar.gz"
curl -I -XHEAD "http://192.168.1.3:6010/sdb1/61178/test/cont1/boto-2.6.0.tar.gz"
curl -I -XHEAD "http://192.168.1.5:6010/sdb1/61178/test/cont1/boto-2.6.0.tar.gz"

Use your own device location of servers:
such as "export DEVICE=/srv/node"
ssh 192.168.1.4 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/61178/1af/3bbe955693bec810b7cfa75b9e8eb1af/"
ssh 192.168.1.3 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/61178/1af/3bbe955693bec810b7cfa75b9e8eb1af/"
ssh 192.168.1.5 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/61178/1af/3bbe955693bec810b7cfa75b9e8eb1af/"

swift@cloud1:~$ ssh 192.168.1.3 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/61178/1af/3bbe955693bec810b7cfa75b9e8eb1af/"
swift@192.168.1.3's password:
ls: 初始化月份字符串出错
ls: 无法访问/srv/node/sdb1/objects/61178/1af/3bbe955693bec810b7cfa75b9e8eb1af/: 没有那个文件或目录
swift@cloud1:~$ ls
openstack
swift@cloud1:~$ swift -A http://127.0.0.1:8080/auth/v1.0 -U test:tester -K testing download cont1 boto-2.6.0.tar.gz
boto-2.6.0.tar.gz [headers 0.039s, total 0.087s, 7.358 MB/s]
swift@cloud1:~$ ls
boto-2.6.0.tar.gz openstack

In SAIO, I upload 3 objects. And there are 3 folders in 4 nodes. But there is no such a folder
“Partition 72
Hash 12365c8a2807d62b0759a4f3bc727d76” which is "swift-get-nodes" returned for me.

My SAIO is just installed the newest one.

swift@qwn-G31M-S2C:/mnt/sdb1/2/node/sdb2$ cd objects
swift@qwn-G31M-S2C:/mnt/sdb1/2/node/sdb2/objects$ ls -f
. .. 336 577
swift@qwn-G31M-S2C:/mnt/sdb1/2/node/sdb2/objects$ cd /mnt/sdb1/3/node/sdb3/objects
swift@qwn-G31M-S2C:/mnt/sdb1/3/node/sdb3/objects$ ls -f
. .. 336 497 577
swift@qwn-G31M-S2C:/mnt/sdb1/3/node/sdb3/objects$ cd /mnt/sdb1/4/node/sdb4/objects
swift@qwn-G31M-S2C:/mnt/sdb1/4/node/sdb4/objects$ ls -f
. .. 336 497 577
swift@qwn-G31M-S2C:/mnt/sdb1/4/node/sdb4/objects$ cd /mnt/sdb1/1/node/sdb1/objects
swift@qwn-G31M-S2C:/mnt/sdb1/1/node/sdb1/objects$ ls -f
. .. 497

swift@qwn-G31M-S2C:~$ swift -A http://127.0.0.1:8080/auth/v1.0 -U test:tester -K testing list container_test1
PPT2.pdf
etc/swift/proxy-server.conf
home/swift/PPT.pdf
swift@qwn-G31M-S2C:~$ swift-get-nodes -a /etc/swift/object.ring.gz test container_test1 PPT2.pdf

Account test
Container container_test1
Object PPT2.pdf

Partition 72
Hash 12365c8a2807d62b0759a4f3bc727d76

Server:Port Device 127.0.0.1:6030 sdb3
Server:Port Device 127.0.0.1:6010 sdb1
Server:Port Device 127.0.0.1:6020 sdb2
Server:Port Device 127.0.0.1:6040 sdb4 [Handoff]

curl -I -XHEAD "http://127.0.0.1:6030/sdb3/72/test/container_test1/PPT2.pdf"
curl -I -XHEAD "http://127.0.0.1:6010/sdb1/72/test/container_test1/PPT2.pdf"
curl -I -XHEAD "http://127.0.0.1:6020/sdb2/72/test/container_test1/PPT2.pdf"
curl -I -XHEAD "http://127.0.0.1:6040/sdb4/72/test/container_test1/PPT2.pdf" # [Handoff]

Use your own device location of servers:
such as "export DEVICE=/srv/node"
ssh 127.0.0.1 "ls -lah ${DEVICE:-/srv/node}/sdb3/objects/72/d76/12365c8a2807d62b0759a4f3bc727d76/"
ssh 127.0.0.1 "ls -lah ${DEVICE:-/srv/node}/sdb1/objects/72/d76/12365c8a2807d62b0759a4f3bc727d76/"
ssh 127.0.0.1 "ls -lah ${DEVICE:-/srv/node}/sdb2/objects/72/d76/12365c8a2807d62b0759a4f3bc727d76/"
ssh 127.0.0.1 "ls -lah ${DEVICE:-/srv/node}/sdb4/objects/72/d76/12365c8a2807d62b0759a4f3bc727d76/" # [Handoff]

Your account "test" actually is "AUTH_test". Try this instead : )

Thanks, Kun Huang.
Your advices are so powerful.

In SAIO, it returned the right folder. and ssh line return the object name I wanted.

swift@qwn-G31M-S2C:/mnt/sdb1/1/node/sdb1/objects$ DEVICE=/mnt/sdb1/2/node
swift@qwn-G31M-S2C:/mnt/sdb1/1/node/sdb1/objects$ ssh 127.0.0.1 "ls -lah ${DEVICE:-/srv/node}/sdb2/objects/577/e45/905d09490feb7978d139ebac97634e45/"
swift@127.0.0.1's password:
总用量 82M
drwxr-xr-x 2 swift swift 34 11月 12 21:28 .
drwxr-xr-x 3 swift swift 45 11月 12 21:28 ..
-rw------- 1 swift swift 82M 11月 12 21:28 1384262912.01738.data

But in the distributed swift in 4 DELL servers, the folder is not right. It is changed to another folder, but it is not exist neither.

The authentication of account and user is tempauth in SAIO, and it is swauth in distributed swift in 4 DELL servers.

Thank you for your warm-hearted help. It really encourage me. And make the testing interesting and fast.

I must try the "swift-get-nodes" line in 4 DELL servers. That will be the system deployed.

Thanks Kun Huang, that solved my question.