Description
Description:
I observed in one long-running application that if the application uses the git2go library to clone the repo or compute the last commit hash from branch/tag then memory is constantly increasing. We run our application in Kubernetes so it leads the pod to out of memory error.
I prepared the hello world application that can easily reproduce the problem. The application clones the repo in the infinite loop and after that, it will remove the tmp directory and run the Free method on every git2go object:
package main
import (
"fmt"
"os"
git2go "github.com/libgit2/git2go/v34"
)
func main() {
fmt.Println("starting...")
iter := 1
for {
fmt.Printf("iteration %d...\n", iter)
err := fetchRepo("https://github.com/kyma-project/serverless")
if err != nil {
fmt.Printf("WARN: %s\n", err.Error())
}
iter++
}
}
const (
branchRefPattern = "refs/remotes/origin"
)
func fetchRepo(repoUrl string) error {
// create tmp dir
repoDir := "/tmp/git2go_test_"
err := os.MkdirAll(repoDir, 0700)
if err != nil {
return err
}
defer os.RemoveAll(repoDir)
// init repo structure
repo, err := git2go.InitRepository(repoDir, true)
if err != nil {
return err
}
defer repo.Free()
// create/reuse remote
remote, err := lookupCreateRemote(repo, repoUrl)
if err != nil {
return err
}
defer remote.Free()
// fetch remote
err = remote.Fetch(nil,
&git2go.FetchOptions{
DownloadTags: git2go.DownloadTagsAll,
}, "")
if err != nil {
return err
}
return nil
}
// lookupCreateRemote looks up the remote with the given name, if it doesn't exist it creates it
func lookupCreateRemote(repo *git2go.Repository, url string) (*git2go.Remote, error) {
remote, err := repo.Remotes.Lookup("origin")
if err == nil {
return remote, nil
}
return repo.Remotes.Create("origin", url)
}The app can be built by running docker build -t <tag> . on this Dockerfile (or you can simply reuse my image pprecel/git2go:latest):
FROM golang:1.22.3-alpine3.20 as builder
WORKDIR /app
RUN apk add --no-cache gcc libc-dev
RUN apk add --no-cache --repository http://dl-cdn.alpinelinux.org/alpine/v3.18/community libgit2-dev=1.5.2-r0
COPY . /app
RUN pwd
RUN go mod tidy
RUN CGO_ENABLED=1 GOOS=linux GOARCH=amd64 go build -o /app/main /app/main.go
FROM alpine:latest
RUN apk add --no-cache --repository http://dl-cdn.alpinelinux.org/alpine/v3.18/community libgit2-dev=1.5.2-r0
COPY --from=builder /app /app
CMD ["/app/main"]The application can be run in every container ecosystem, so docker or Kubernetes systems will show the right results:
docker run -d --name git2go-2 pprecel/git2go:latest
or
kubectl run git2go --image=pprecel/git2go:latest
On my machine, I observed that after a night the memory usage increased from 28Mi to almost 3000Mi and it's still increasing.
. Example:
kubectl top pods
NAME CPU(cores) MEMORY(bytes)
git2go 532m 20Mi
after a night
kubectl top pods
NAME CPU(cores) MEMORY(bytes)
git2go 532m 3012Mi