Does Concurrency Work in Docker?

Server Docker
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1

my docker file is

# Use the official Swift image from the Docker Hub
FROM swift:5.10

# Set a working directory inside the container
WORKDIR /app

# Copy the Package.swift and Sources directory into the container at /app
COPY Package.swift ./
COPY Sources ./Sources

# Build the Swift package
RUN swift build

# Run the executable produced by the build
CMD ["swift", "run", "SomeFile"]

and my code contains

import Foundation

#if canImport(FoundationNetworking)
import FoundationNetworking
#endif
#if canImport(_Concurrency)
import _Concurrency
#endif

....

let (data, _) = try await URLSession.shared.data(for: request)

but got

2.409 /app/Sources/MyFile.swift:34:57: error: value of type 'URLSession' has no member 'data'
2.409 let (data, _) = try await URLSession.shared.data(for: request)
2.409 ~~~~~~~~~~~~~~~~~ ^~~~

do you know how to fix it?

2

Corelibs foundation is a different implementation on Linux currently, and it has many missing APIs. So what youā€™re experiencing is a different library on Linux not having the api you expect.

Thereā€™s an active process to resolve this weird situation by implementing foundation in swift which is over here: GitHub - apple/swift-foundation: The Foundation project and then both platforms will be using the exact same implementation, resolving the issue youā€™ve hit.

In practice for http clients though Iā€™d recommend using the async http client library anyway: GitHub - swift-server/async-http-client: HTTP client library built on SwiftNIO as itā€™s more geared towards the server ecosystem.

Hope this helps

2 Likes
3

thanks a lot it does help!

1 Like
4

Unless you happen to use something of that stable and solid ā€ždeprecatedā€œ API thatā€˜s not going to be implemented in the new one

5

Actually, just today Jonathan submitted a PR Add async URLSession methods by jrflat Ā· Pull Request #4970 Ā· apple/swift-corelibs-foundation Ā· GitHub implementing the missing methods in the corelibs URLSession :slight_smile:

So while the medium and long term story remains about GitHub - apple/swift-foundation: The Foundation project this specific issue would also be fixed in corelibs :slight_smile:

7 Likes
6

Thatā€˜s very good news. There are so many important pull requests lingering, a bit of traction would suit that project very well.

1 Like