Rootless libpod.conf should fill in an appropriate tmp_dir

[llchan]

/kind bug

Description

When a libpod.conf is specified via --config, an omitted tmp_dir does not fall back to the default ($XDG_RUNTIME_DIR/libpod/tmp) like it does when --config is not specified. It remains at the empty string, which leads to a fairly obvious but not very user-friendly error downstream.

Steps to reproduce the issue:

1. Copy the default libpod.conf (which has tmp_dir commented out)

2. podman --config libpod.conf info

Describe the results you received:

DEBU[0000] Using tmp dir                                
DEBU[0000] Set libpod namespace to ""                   
DEBU[0000] [graphdriver] trying provided driver "vfs"   
ERRO[0000] could not get runtime: error creating tmpdir : mkdir : no such file or directory 

Describe the results you expected:

DEBU[0000] Using tmp dir /run/user/XXXXX/libpod/tmp     
DEBU[0000] Set libpod namespace to ""                   
DEBU[0000] [graphdriver] trying provided driver "vfs"

Output of podman version:

RemoteAPI Version:  1
Go Version:         go1.11
Git Commit:         eb6243226a08254f15657c3728bb4dd8949ee6cd
Built:              Thu Feb 21 17:13:21 2019
OS/Arch:            linux/amd64

[llchan]

This diff fixes things (awaiting approval to submit PRs, but pasting this here since it's small and harmless):

diff --git a/libpod/runtime.go b/libpod/runtime.go
index 94dbf37d..a8bb4b9f 100644
--- a/libpod/runtime.go
+++ b/libpod/runtime.go
@@ -472,6 +472,12 @@ func NewRuntimeFromConfig(configPath string, options ...RuntimeOption) (runtime
    runtime.config.OCIRuntime = defaultRuntimeConfig.OCIRuntime
    runtime.config.StorageConfig = storage.StoreOptions{}

+   tmpDir, err := getDefaultTmpDir()
+   if err != nil {
+       return nil, err
+   }
+   runtime.config.TmpDir = tmpDir
+
    // Check to see if the given configuration file exists
    if _, err := os.Stat(configPath); err != nil {
        return nil, errors.Wrapf(err, "error checking existence of configuration file %s", configPath)

On a more general note, is there a reason why we don't initialize with defaultRuntimeConfig, and let the user-supplied config overwrite (i.e. more similar to what NewRuntime does)?

[giuseppe]

the patch LGTM

[rhatdan]

Could someone open this as a PR?

[rhatdan]

This seems to be working for me in current podman?

$ podman --log-level debug --config ~/.config/containers/libpod.conf info  2>&1 | grep -i "Using tmp"
time="2019-02-23T06:11:43-05:00" level=debug msg="Using tmp dir /run/user/3267/libpod/tmp" 
$ grep tmp ~/.config/containers/libpod.conf

[llchan]

@rhatdan maybe you need to remove your existing db config?

[giuseppe]

I see the same problem with a fresh storage. I confirm the patch above fixes the problem.

@llchan could you open a PR?

[llchan]

I unfortunately cannot yet, still pending approval from manager and he's out of town for the week. Will do as soon as I can. If you'd like to file it on my behalf feel free to.

[rhatdan]

Ok, @llchan We would love to have you to contribute, once you get permission.. @giuseppe Can you open a PR.

[giuseppe]

I've opened a PR here: #2515