gcloud submit : specify Dockerfile with --file parameter doesn't seem to work

Question

In my project, Dockerfiles are not stored in the same place that the files I want to COPY in my image. Like :

root
     Dockerfiles:
          app_name1:
              dockerfile1
          ...
    folder
          app1
          app2
          ...
cloudbuild

I have a cloudbuild.yaml like that :

steps:
- name: gcr.io/cloud-builders/docker
  args:
  - build
  - '--tag=eu.gcr.io/$PROJECT_ID/${_IMAGE_NAME}:${_STAGE}'
  - **'-f ./Dockerfiles/${_IMAGE_NAME}/Dockerfile'**
  - .
images: [
    'eu.gcr.io/$PROJECT_ID/${_IMAGE_NAME}'
]

and I build the image from root like that :

gcloud builds submit .
      --config=cloudbuild.yaml
      --substitutions [...]
      .

I checked inside my GCP Bucket, the source specified in gcloud submit (.) is successfuly uploaded and so should be accessible in ./workspace/.

But the build fails with the following error :

unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat /workspace/ .: no such file or directory

It seems like he doesn't want to use the Dockerfile specified in the --file argument. And I can't manage to find an exemple of cloudbuild.yaml using this argument. Any idea on what's happening ?

Answer 1

It's possibly that, if your file structure is accurate, you're referencing the Dockerfile path incorrectly.

A sanity check would be to run the docker build locally first:

PROJECT_ID="..."
_IMAGE_NAME="app1"
_STAGE="dev"

docker build \
--tag=gcr.io/$PROJECT_ID/${_IMAGE_NAME}:${_STAGE} \
--file=./Dockerfiles/${_IMAGE_NAME}/Dockerfile \
.

The following works for me:

.
├── cloudbuild.yaml
├── Dockerfiles
│   └── app1
│       └── Dockerfile
└── folder
    └── app1
        └── greeting.txt

And:

./Dockerfiles/app1/Dockerfile:

FROM busybox

WORKDIR /tmp

COPY ./folder/app1/greeting.txt ./greeting.txt

ENTRYPOINT ["cat","/tmp/greeting.txt"]

And:

cloudbuild.yaml:

steps:
  - name: docker
    args:
      - build
      - --tag=gcr.io/$PROJECT_ID/${_IMAGE_NAME}:${_STAGE}
      - --file=./Dockerfiles/${_IMAGE_NAME}/Dockerfile
      - .
images:
  - gcr.io/$PROJECT_ID/${_IMAGE_NAME}

And:

PROJECT="..."
QUESTION="64972175"
gcloud builds submit . \
--config=./cloudbuild.yaml \
--substitutions=_IMAGE_NAME=app1,_STAGE="dev" \
--project=${PROJECT}

Yields:

BUILD
Pulling image: docker
Using default tag: latest
latest: Pulling from library/docker
Digest: sha256:9170b902404a630a982a2a6473442d3e2cc2342b66345f7a9cf148f8affcf5d3
Status: Downloaded newer image for docker:latest
docker.io/library/docker:latest
Sending build context to Docker daemon  6.144kB
Step 1/4 : FROM busybox
latest: Pulling from library/busybox
Digest: sha256:a9286defaba7b3a519d585ba0e37d0b2cbee74ebfe590960b0b1d6a5e97d1e1d
Status: Downloaded newer image for busybox:latest
 ---> f0b02e9d092d
Step 2/4 : WORKDIR /tmp
 ---> Running in 6ffe8d2b3f56
Removing intermediate container 6ffe8d2b3f56
 ---> 51dcdc2e141a
Step 3/4 : COPY ./folder/app1/greeting.txt ./greeting.txt
 ---> 7459813216f3
Step 4/4 : ENTRYPOINT ["cat","/tmp/greeting.txt"]
 ---> Running in 25362a24391b
Removing intermediate container 25362a24391b
 ---> 398b1f4a60e2
Successfully built 398b1f4a60e2
Successfully tagged gcr.io/[[PROJECT]]/app1:dev
PUSH
Pushing gcr.io/[[PROJECT]]/app1
The push refers to repository [gcr.io/[[PROJECT]]/app1]
8b5d68988e85: Preparing
d2421964bad1: Preparing
d2421964bad1: Layer already exists
8b5d68988e85: Pushed
dev: digest: sha256:d33bd458b8df930fc3338110f8369743ac74068b8a527c5f59958ee1ce1182ff size: 734
DONE