How to use libpod as library in my own program?

[towe75]

/kind feature

Build a stand alone program with libpod features

I'd like to work on integrating podman and nomad, see also hashicorp/nomad#5312

So i started out to build a test program where i want to get familiar with the libpod api before building the actual nomad plugin.

I did not have any trouble building the tool but i can not manage to get a libpod.Runtime object.

Also there seems to be no official documentation on using libpod as library (the project name, however, suggests that it should be possible :-) )

Steps to reproduce the issue:

1. write a cli tool with this source code

package main

import (
	"context"

	"github.com/containers/libpod/libpod"
	"github.com/sirupsen/logrus"
)

func main() {

	logrus.SetLevel(logrus.TraceLevel)
	logrus.Info("Getting Runtime")

	ctx := context.TODO()
	runtime, err := libpod.NewRuntime(ctx)
	if err != nil {
		logrus.Fatal("Error creating runtime", err)
		return
	}

	containers, err := runtime.GetContainers()
	if err != nil {
		logrus.Fatal("Error listing containers", err)
		return
	}

	for _, c := range(containers) {
		logrus.Info("Found container", c.Name())

	}

	runtime.Shutdown(false)

2. Run the program

The program will block forever, it can not initialize the runtime at all

Debug info

Logging output

INFO[0000] Getting Runtime
DEBU[0000] Initializing boltdb state at /var/lib/containers/storage/libpod/bolt_state.db
DEBU[0000] Using graph driver overlay
DEBU[0000] Using graph root /var/lib/containers/storage
DEBU[0000] Using run root /var/run/containers/storage
DEBU[0000] Using static dir /var/lib/containers/storage/libpod
DEBU[0000] Using tmp dir /var/run/libpod
DEBU[0000] Using volume path /var/lib/containers/storage/volumes
DEBU[0000] Set libpod namespace to ""
DEBU[0000] [graphdriver] trying provided driver "overlay"

Process list

153 ? Ss 0:00 /bin/bash
820 ? Sl+ 0:00 _ ./libpod-test
827 ? Sl+ 0:00 _ storage-mountfrom /var/lib/containers/storage

Questions

1. do i miss any initialization step? Maybe you can clearify the start/stop cycle of the library a bit.
2. it would be helpful to build and link the godoc for libpod. Getting started was rather complex

For sure i miss some important initialization step but i can not find any clue in the github repo.

Thank you,

Thomas

[mheon]

I think you're missing the storage reexec.Init() call - I'm not at a computer so I can't get the exact invocation, but you can find it in cmd/podman/main.go

…

On Thu, Jun 27, 2019, 07:31 Thomas Weber ***@***.***> wrote: /kind feature *Build a stand alone program with libpod features* I'd like to work on integrating podman and nomad, see also hashicorp/nomad#5312 <hashicorp/nomad#5312> So i started out to build a test program where i want to get familiar with the libpod api before building the actual nomad plugin. I did not have any trouble building the tool but i can not manage to get a libpod.Runtime object. Also there seems to be no official documentation on using libpod as library (the project name, however, suggests that it should be possible :-) ) *Steps to reproduce the issue:* 1. write a cli tool with this source code package main import ( "context" "github.com/containers/libpod/libpod" "github.com/sirupsen/logrus" ) func main() { logrus.SetLevel(logrus.TraceLevel) logrus.Info("Getting Runtime") ctx := context.TODO() runtime, err := libpod.NewRuntime(ctx) if err != nil { logrus.Fatal("Error creating runtime", err) return } containers, err := runtime.GetContainers() if err != nil { logrus.Fatal("Error listing containers", err) return } for _, c := range(containers) { logrus.Info("Found container", c.Name()) } runtime.Shutdown(false) 1. Run the program The program will block forever, it can not initialize the runtime at all *Debug info* Logging output INFO[0000] Getting Runtime DEBU[0000] Initializing boltdb state at /var/lib/containers/storage/libpod/bolt_state.db DEBU[0000] Using graph driver overlay DEBU[0000] Using graph root /var/lib/containers/storage DEBU[0000] Using run root /var/run/containers/storage DEBU[0000] Using static dir /var/lib/containers/storage/libpod DEBU[0000] Using tmp dir /var/run/libpod DEBU[0000] Using volume path /var/lib/containers/storage/volumes DEBU[0000] Set libpod namespace to "" DEBU[0000] [graphdriver] trying provided driver "overlay" Process list 153 ? Ss 0:00 /bin/bash 820 ? Sl+ 0:00 _ ./libpod-test 827 ? Sl+ 0:00 _ storage-mountfrom /var/lib/containers/storage *Questions* 1. do i miss any initialization step? Maybe you can clearify the start/stop cycle of the library a bit. 2. it would be helpful to build and link the godoc for libpod. Getting started was rather complex For sure i miss some important initialization step but i can not find any clue in the github repo. Thank you, Thomas — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#3445>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB3AOCHQSWDKXZLHDZPDJH3P4SQJFANCNFSM4H33AMRA> .

[towe75]

@mheon you made my day!
Still having some better documentation would be awesome.

Thank you!

Cheers,

Thomas