Add extra location to nginx-s3-gateway image

[MuriloCouceiro]

Hello, I'm trying to add extra locations to the S3 gateway that map a local folder in order to upload or download files.

When trying to add these locations to the nginxinc/nginx-s3-gateway image configs, these are overwritten with the original image ones.

I'm trying with the following file structure and Dockerfile, however, it is not working as described above. Can you tell me if I'm doing anything wrong?

Dockerfile

FROM nginxinc/nginx-s3-gateway

ENV S3_BUCKET_NAME "bucket"
ENV AWS_ACCESS_KEY_ID "aaaa"
ENV AWS_SECRET_ACCESS_KEY "aaaa"
ENV S3_SERVER "aaaaa"
ENV S3_SERVER_PORT "80"
ENV S3_SERVER_PROTO "http"
ENV S3_REGION "us-east-1"
ENV S3_STYLE "path"
ENV DEBUG "false"
ENV AWS_SIGS_VERSION "4"
ENV ALLOW_DIRECTORY_LIST "true"
ENV PROVIDE_INDEX_PAGE "true"
ENV NGINX_ENTRYPOINT_QUIET_LOGS "true"

COPY etc/nginx/conf.d /etc/nginx/conf.d 

COPY . /var/uploads

s3_server.conf example

location /local/health {
    return 200;
}

File Structure

Thanks in advance

[4141done]

Hello, thanks for reaching out and sorry to hear you are having problems modifying the image. There are two strategies you can use to modify the NGINX configuration.

I created a gist showing my understanding of your question.

The directory structure is as follows:

.
├── Dockerfile
├── etc
│   └── nginx
│       └── conf.d
│           ├── gateway
│           │   └── s3_server.conf
│           └── modifications.conf
└── images
    └── whale.jpg

Then, running

docker build -t my_image:1 .

to build the image.

And

docker run -it custom_s3:1 /bin/bash

Shows the modified files in the correct locations. They will be loaded by this statement in the main configuration.

Another method

Alternately, you could build your docker image using this repository checked out locally, make your modifications to
s3_server.conf.template then add your additional files (the ones you want to add to var/uploads) in the Dockerfile that corresponds to your build (open source one is here. You'd place it with the other COPY statements.

Then build:

docker build -f Dockerfile.oss\
      --tag nginx-s3-gateway --tag nginx-s3-gateway:oss.

Hope this helps. Please let me know if anything is not clear or if I misunderstood your problem.

[4141done]

Apologies, I gave you incorrect advice (I'm still learning as a maintainer of this project).

Any files you include in /etc/nginx/conf.d will be included in the http context. This can be helpful, but in your case you don't want to create a whole new virtual server.

However, the specific file /etc/nginx/conf.d/gateway/s3_server.conf file is included in the main server block for the s3 gateway (see here) so you can add location directives directly there.

That means if you want to add an extra location block you'd want to override that file. The gist I originally posted has an example of this and I've confirmed that building in this way does override the file.

# Start the container and inspect the templated files
docker run -p 80:80 -it my_image:1 /bin/bash
root@83e7f37acf15:/# cat /etc/nginx/conf.d/gateway/s3_server.conf
location /local/health {
    return 200;
}

location /foo/bar {
    return  200 "this is foo/bar";
}

root@83e7f37acf15:/# exit



# Start the container using the normal command
docker run -p 80:80 my_image:1
S3 Backend Environment
Access Key ID: aaaa
Origin: http://bucket.google.com:80
Region: us-east-1
Addressing Style: path
AWS Signatures Version: v4
DNS Resolvers:  192.168.65.7
Directory Listing Enabled: true
Directory Listing Path Prefix:
Provide Index Pages Enabled: true
Append slash for directory enabled:
Stripping the following headers from responses: x-amz-;
CORS Enabled: 0
2023/11/29 22:44:04 [notice] 1#1: using the "epoll" event method
2023/11/29 22:44:04 [notice] 1#1: nginx/1.25.3
2023/11/29 22:44:04 [notice] 1#1: built by gcc 12.2.0 (Debian 12.2.0-14)
2023/11/29 22:44:04 [notice] 1#1: OS: Linux 6.4.16-linuxkit
2023/11/29 22:44:04 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/11/29 22:44:04 [notice] 1#1: start worker processes
2023/11/29 22:44:04 [notice] 1#1: start worker process 206
2023/11/29 22:44:04 [notice] 1#1: start cache manager process 208
2023/11/29 22:44:04 [notice] 1#1: start cache loader process 210

Summary

Add your changes to a file called /etc/nginx/conf.d/gateway/s3_server.conf and copy it into the image on build as shown in the gist.

[MuriloCouceiro]

Thanks again for the answer!

Without that modification.conf file, I think it is the same as I initially tested this. I've tried once again and if running the container without the entrypoint, somehow the files are overwritten with the original ones.

Here are some prints with red highlighting showing the behaviour. First I execute the commands you've shown here and after the server is running, I cannot reach the desired location.

When looking into the s3_server.conf file it turns out that it does not contain the changes I've made (2nd image).

[MuriloCouceiro]

@4141done any news on this?

[4141done]

Hi @MuriloCouceiro ! Sorry for the delay. You are correct that in my example gist the contents of s3_server.conf are being overwritten when the normal docker entrypoint is used.

The reason for this is that the gateway project takes the files in /etc/nginx/templates, runs envsubst on them at startup, and outputs the files to /etc/nginx/conf.d.

In my gist, I mistakenly put the file in /etc/nginx/conf.d/gateway while was overwritten by that process. Apologies for the bad initial answer. I am still learning as a maintainer on this project 🙏 .

So here's a new solution that I've tested.

1. Place your modified file in etc/nginx/templates/gateway/s3_server.conf.template (it can be anywhere but I find it helps to match the folder structure for the docker COPY command).

.
├── Dockerfile
├── etc
│   └── nginx
│       └── templates
│           └── gateway
│               └── s3_server.conf.template

The .template part of the name is important. Because the project includes this file by name the entire name must be exactly s3_server.conf.template
2. Adjust the COPY command in the Dockerfile to: COPY etc/nginx/templates /etc/nginx/templates
3. Build and run the image.

Here are my results.
The s3_server.conf.template contains:

location /local/health {
    return 200;
}

location /foo/bar {
    return  200 "this is foo/bar";
}

Starting the docker container and the following logs show the location defined in my custom s3_server.conf.template being served:

docker run --platform linux/amd64 -it -p 80:80 my_image:1
S3 Backend Environment
Access Key ID: aaaa
Origin: http://bucket.google.com:80
Region: us-east-1
Addressing Style: path
AWS Signatures Version: v4
DNS Resolvers:  192.168.65.7
Directory Listing Enabled: true
Directory Listing Path Prefix:
Provide Index Pages Enabled: true
Append slash for directory enabled:
Stripping the following headers from responses: x-amz-;
CORS Enabled: 0
2023/12/09 00:26:15 [notice] 1#1: using the "epoll" event method
2023/12/09 00:26:15 [notice] 1#1: nginx/1.25.3
2023/12/09 00:26:15 [notice] 1#1: built by gcc 12.2.0 (Debian 12.2.0-14)
2023/12/09 00:26:15 [notice] 1#1: OS: Linux 6.4.16-linuxkit
2023/12/09 00:26:15 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2023/12/09 00:26:15 [notice] 1#1: start worker processes
2023/12/09 00:26:15 [notice] 1#1: start worker process 75
2023/12/09 00:26:15 [notice] 1#1: start cache manager process 76
2023/12/09 00:26:15 [notice] 1#1: start cache loader process 77
192.168.65.1 - - [09/Dec/2023:00:26:18 +0000] "GET /foo/bar HTTP/1.1" 200 15 "-" "curl/8.1.2" "-"
2023/12/09 00:26:18 [info] 75#75: *1 client 192.168.65.1 closed keepalive connection

Testing requests to the new endpoint:

curl localhost/foo/bar
this is foo/bar

Let me know if that works for you! If it does I'll be adding some guidance to the README to make this method of modifying the project clear for future users.

[MuriloCouceiro]

Hello, @4141done! This works for me as well!
Thank you so much for the help!