Description
Description
The "config" (or convert) subcommand of Docker Compose should write the output to a file instead of the standard output when I use the --output output.yml parameter. It creates the file but doesnt write anything into it. The result is an empty file.
Steps To Reproduce
- Create any compose file
- run
docker compose config --output output.yml - Test the output:
cat output.yml
Compose Version
The original: `Docker Compose version v2.13.0`
The custom build for testing from the Compose v2 repo: `Docker Compose version v2.14.2-20-gfd353ffa.m`
Docker Environment
Client:
Context: desktop-linux
Debug Mode: false
Plugins:
buildx: Docker Buildx (Docker Inc., v0.9.1)
compose: Docker Compose (Docker Inc., v2.13.0)
dev: Docker Dev Environments (Docker Inc., v0.0.5)
extension: Manages Docker extensions (Docker Inc., v0.2.16)
sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc., 0.6.0)
scan: Docker Scan (Docker Inc., v0.22.0)
Server:
Containers: 24
Running: 20
Paused: 0
Stopped: 4
Images: 68
Server Version: 20.10.21
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
userxattr: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
Cgroup Version: 2
Plugins:
Volume: local
Network: bridge host ipvlan macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
Swarm: inactive
Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 770bd0108c32f3fb5c73ae1264f7e503fe7b2661
runc version: v1.1.4-0-g5fd4c4d
init version: de40ad0
Security Options:
seccomp
Profile: default
cgroupns
Kernel Version: 5.15.49-linuxkit
Operating System: Docker Desktop
OSType: linux
Architecture: aarch64
CPUs: 3
Total Memory: 3.841GiB
Name: docker-desktop
ID: GHHA:R5X5:PFCQ:6VI6:SDLO:JQNB:JKVS:BGVL:7PF3:W2DN:5XHT:UDYB
Docker Root Dir: /var/lib/docker
Debug Mode: false
HTTP Proxy: http.docker.internal:3128
HTTPS Proxy: http.docker.internal:3128
No Proxy: hubproxy.docker.internal
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
hubproxy.docker.internal:5000
127.0.0.0/8
Live Restore Enabled: false
Anything else?
I checked the sourcecode and find this part in the runConvert method.
compose/cmd/compose/convert.go
Line 162 in 7a8d157
The type of out is io.Writer which is good for the default destination (standard output) but when I set the --output option, it saaves a bufio.Writer in out. I found out that bufio.Writer should be flushed, so I tested the theory and it worked, but then the standard output could not be the default value of out because of the different types. So I guess I could have create a new variable in the "if" block, write the content like this
bufout.Write(content)
bufout.Flush()
and return, but I don't know if this is the best solution so or I could flush the writer some other way. If you think it would be the right way, I am happy to send a pull request.