Using COPY --from with the Go SDK | Dagger | Page 1

dull kraken Jan 11, 2023, 7:17 PM

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I'm trying to using the COPY --from command to get a directory from an image that is not part of the multi-stage build. in Dagger.

Here is an example snippet from a Dockerfile:

FROM vendor/image
COPY --from=another-vendor/another-image /opt/vendor-deps /opt/vendor-deps

Is there an equivalent way to perform this in the Go SDK?

high heart Jan 11, 2023, 7:23 PM

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Yes, you can definitely do that. Let me find a few pointers for you

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This guide might be a useful place to start: https://docs.dagger.io/205271/replace-dockerfile

Replace a Dockerfile with Go | Dagger

Introduction

topaz escarp Jan 11, 2023, 7:34 PM

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@dull kraken you can use the Container().From("address"). step to get whatever directory or file from other container. Here's an example:

package main

import (
    "context"
    "fmt"

    "dagger.io/dagger"
)

func main() {
    c, err := dagger.Connect(context.Background())
    if err != nil {
        panic(err)
    }
    defer c.Close()

    ctx := context.Background()

    helloDir := c.Container().From("hello-world").Directory("/")

    out, err := c.Container().From("alpine").
        WithDirectory("/hello", helloDir).
        WithExec([]string{"/hello/hello"}).Stdout(ctx)

    fmt.Println(out, err)
}

#Using COPY --from with the Go SDK