NextJS Docker Container with .env.production

Question

When testing and using my NextJS Application with .env.local everything works great. However, when I do a production build to deploy, it can't find the .env.production values (even though its an exact copy from .env.local for now). When I added an endpoint that does a console.log(process.env) none of the .env.production values are present.

Here's my Dockerfile

# Install dependencies only when needed
FROM node:alpine AS deps
# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.
RUN apk add --no-cache libc6-compat
WORKDIR /app
COPY package.json yarn.lock ./
RUN yarn install --frozen-lockfile

# Rebuild the source code only when needed
FROM node:alpine AS builder
WORKDIR /app
COPY . .
COPY --from=deps /app/node_modules ./node_modules
RUN yarn build && yarn install --production --ignore-scripts --prefer-offline

# Production image, copy all the files and run next
FROM node:alpine AS runner
WORKDIR /app

ENV NODE_ENV production

RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

# You only need to copy next.config.js if you are NOT using the default configuration
# COPY --from=builder /app/next.config.js ./
COPY --from=builder /app/public ./public
COPY --from=builder --chown=nextjs:nodejs /app/.next ./.next
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./package.json

USER nextjs

EXPOSE 3000

# Next.js collects completely anonymous telemetry data about general usage.
# Learn more here: https://nextjs.org/telemetry
# Uncomment the following line in case you want to disable telemetry.
# ENV NEXT_TELEMETRY_DISABLED 1

CMD ["yarn", "start"]

and I build the image with this command:

docker build -t my-next-project .

When doing a manual build:

next build

it says in the console:

info  - Loaded env from /Users/name/source/my-next-project/.env.local
info  - Loaded env from /Users/name/source/my-next-project/.env.production

So it finds the two .env files...not sure what's not working here.

Edit:

Here's the log from running my docker build command docker build -t app-container .

[+] Building 140.1s (14/21)                                                                                                                                                                                                                                              
 => => transferring dockerfile: 37B                                                                                                                                                                                                                                 0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                                                   0.0s
 => => transferring context: 2B                                                                                                                                                                                                                                     0.0s
 => [internal] load metadata for docker.io/library/node:alpine                                                                                                                                                                                                      1.4s
 => [auth] library/node:pull token for registry-1.docker.io                                                                                                                                                                                                         0.0s
[+] Building 140.2s (14/21)                                                                                                                                                                                                                                              
 => => transferring context: 290.52MB                                                                                                                                                                                                                              17.2s
 => [deps 1/5] FROM docker.io/library/node:alpine@sha256:f372a9ffcec27159dc9623bad29997a1b61eafbb145dbf4f7a64568be2f59b99                                                                                                                                           0.0s
 => CACHED [deps 2/5] RUN apk add --no-cache libc6-compat                                                                                                                                                                                                           0.0s
 => CACHED [deps 3/5] WORKDIR /app                                                                                                                                                                                                                                  0.0s
 => [deps 4/5] COPY package.json yarn.lock ./                                                                                                                                                                                                                       0.4s
[+] Building 140.4s (14/21)                                                                                                                                                                                                                                              
 => [deps 1/5] FROM docker.io/library/node:alpine@sha256:f372a9ffcec27159dc9623bad29997a1b61eafbb145dbf4f7a64568be2f59b99                                                                                                                                           0.0s
[+] Building 140.5s (14/21)                                                                                                                                                                                                                                              
 => CACHED [deps 3/5] WORKDIR /app                                                                                                                                                                                                                                  0.0s
[+] Building 152.6s (22/22) FINISHED                                                                                                                                                                                                                                     
 => [internal] load build definition from Dockerfile                                                                                                                                                                                                                0.0s
 => => transferring dockerfile: 37B                                                                                                                                                                                                                                 0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                                                   0.0s
 => => transferring context: 2B                                                                                                                                                                                                                                     0.0s
 => [internal] load metadata for docker.io/library/node:alpine                                                                                                                                                                                                      1.4s
 => [auth] library/node:pull token for registry-1.docker.io                                                                                                                                                                                                         0.0s
 => [internal] load build context                                                                                                                                                                                                                                  17.6s 
 => => transferring context: 290.52MB                                                                                                                                                                                                                              17.2s 
 => [deps 1/5] FROM docker.io/library/node:alpine@sha256:f372a9ffcec27159dc9623bad29997a1b61eafbb145dbf4f7a64568be2f59b99                                                                                                                                           0.0s 
 => CACHED [deps 2/5] RUN apk add --no-cache libc6-compat                                                                                                                                                                                                           0.0s 
 => CACHED [deps 3/5] WORKDIR /app                                                                                                                                                                                                                                  0.0s 
 => [deps 4/5] COPY package.json yarn.lock ./                                                                                                                                                                                                                       0.4s 
 => CACHED [builder 2/6] WORKDIR /app                                                                                                                                                                                                                               0.0s 
 => [builder 3/6] COPY . .                                                                                                                                                                                                                                         10.6s 
 => [deps 5/5] RUN yarn install --frozen-lockfile                                                                                                                                                                                                                  33.0s
 => [builder 4/6] ADD ./.env.production ./.env.production                                                                                                                                                                                                           0.1s
 => [builder 5/6] COPY --from=deps /app/node_modules ./node_modules                                                                                                                                                                                                 3.0s
 => [builder 6/6] RUN NODE_ENV=production yarn build && yarn install --production --ignore-scripts --prefer-offline                                                                                                                                                89.7s
 => CACHED [runner 3/8] RUN addgroup -g 1001 -S nodejs                                                                                                                                                                                                              0.0s 
 => CACHED [runner 4/8] RUN adduser -S nextjs -u 1001                                                                                                                                                                                                               0.0s 
 => [runner 5/8] COPY --from=builder /app/public ./public                                                                                                                                                                                                           0.1s 
 => [runner 6/8] COPY --from=builder --chown=nextjs:nodejs /app/.next ./.next                                                                                                                                                                                       0.4s 
 => [runner 7/8] COPY --from=builder /app/node_modules ./node_modules                                                                                                                                                                                               1.8s 
 => [runner 8/8] COPY --from=builder /app/package.json ./package.json                                                                                                                                                                                               0.0s 
 => exporting to image                                                                                                                                                                                                                                              1.9s
 => => exporting layers                                                                                                                                                                                                                                             1.9s
 => => writing image sha256:0e529630769589eefbdb0871e7024ea7f296db978c45102e7804e489d6d2f712                                                                                                                                                                        0.0s
 => => naming to docker.io/library/app-container

Answer 1

If you are NOT using the default configuration you have to uncomment:

COPY --from=builder /app/next.config.js ./

in this part, you have to copy all your production files to container like your .env files from builder like:

COPY --from=builder /app/.env.production ./