github.com/containers/podman/v5@v5.1.0-rc1/docs/source/markdown/options/build-context.md (about)

     1  ####> This option file is used in:
     2  ####>   podman build, farm build
     3  ####> If file is edited, make sure the changes
     4  ####> are applicable to all of those.
     5  #### **--build-context**=*name=value*
     6  
     7  Specify an additional build context using its short name and its location.
     8  Additional build contexts can be referenced in the same manner as we access
     9  different stages in COPY instruction.
    10  
    11  Valid values are:
    12  
    13  * Local directory – e.g. --build-context project2=../path/to/project2/src (This option is not available with the remote Podman client. On Podman machine setup (i.e macOS and Windows) path must exists on the machine VM)
    14  * HTTP URL to a tarball – e.g. --build-context src=https://example.org/releases/src.tar
    15  * Container image – specified with a container-image:// prefix, e.g. --build-context alpine=container-image://alpine:3.15, (also accepts docker://, docker-image://)
    16  
    17  On the Containerfile side, reference the build context on all
    18  commands that accept the “from” parameter. Here’s how that might look:
    19  
    20  ```dockerfile
    21  FROM [name]
    22  COPY --from=[name] ...
    23  RUN --mount=from=[name] …
    24  ```
    25  
    26  The value of [name] is matched with the following priority order:
    27  
    28  * Named build context defined with --build-context [name]=..
    29  * Stage defined with AS [name] inside Containerfile
    30  * Image [name], either local or in a remote registry