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= Build Singularity Containers from Recipes =

Because you do not have administrative privileges, you cannot build a Singularity container from a Singularity recipe file on Cypress.

== Build Remotely on the Cloud ==
* You can build a Singularity container from a recipe on [https://cloud.sylabs.io/builder Sylabs Cloud].
* On Cypress, use the provided '''singularity pull...''' command to construct the image file from the cloud such as the following, substituting your chosen values for '''sylabsID''', '''myCollection''', '''myImage''', and '''myTag'''.

{{{
[tulaneID@cypress01-009 ~]$singularity pull --arch amd64 library://sylabsID/myCollection/myImage:myTag
}}}

=== Signing Your Container File ===

* You may encounter the following messages,
{{{
WARNING: integrity: signature not found for object group 1
WARNING: Skipping container verification
}}}

* If so, then you can sign your container file via the following.
 * Create or update your Sylabs token as needed at [https://cloud.sylabs.io/tokens Sylabs Cloud Tokens]
 * Copy the new Sylabs token provided in the above as needed in your clipboard.
 * Confirm your remote login in your interactive session by entering the command 
{{{
[tulaneID@cypress01-009 ~]$singularity remote login
}}}
 * Paste the new Sylabs token provided as needed at the prompt.
 * Substitute your chosen values for '''sylabsID''', '''myCollection''', '''myImage''', and '''myTag''' in the URL !https://cloud.sylabs.io/library/sylabsID/myCollection/myImage
 * Observe on the Sylabs web page for the image the label '''Image is Unsigned'''.
 * Click on the button labeled '''Sign Image''', and at the terminal enter the commands in the resulting pop-up window, such as the following.
{{{
[tulaneID@cypress01-009 ~]$singularity pull sylabsID_mycollection.sif library://sylabsID/mycollection/myimage:mytag
[tulaneID@cypress01-009 ~]$singularity key list
[tulaneID@cypress01-009 ~]$singularity sign --keyidx 0 sylabsID_mycollection.sif
Signing image: cb4sylabs_mycollection.sif
Signature created and applied to cb4sylabs_mycollection.sif
[tulaneID@cypress01-009 ~]$singularity push sylabsID_mycollection.sif library://sylabsID/mycollection/myimage:mytag
3.6MiB / 3.6MiB [==============================================================================] 100 % 11.8 MiB/s 0s
}}}
 * Confirm on the Sylabs web page for the image, refreshing the page as needed, the label '''Image is Signed'''.

== Build on Your Local Machine ==

* You could build a Linux machine and install Singularity.
* On Windows 11 or Windows 10 version 2004 and higher (Build 19041 and higher)
 * Install Windows Subsystem for Linux, version 2 ('''WSL 2'''). See [https://learn.microsoft.com/en-us/windows/wsl/install Install WSL].
 * Install Singularity. See [https://sylabs.io/docs/ SingularityCE Documentation].
* As an alternative to SingularityCE, on your local machine (Linux or WSL 2) you could install Apptainer.
 * Apptainer will build '''.sif''' files compatible with Singularity. See [[https://apptainer.org/docs/user/latest/singularity_compatibility.html#sif-image-compatibility | SIF Image Compatibility]].
 * See [[https://apptainer.org/documentation/ | Apptainer Documentation ]].
* Then upload the resulting '''.sif''' file to Cypress from your local machine using scp. (See [[cypress/FileTransfer#scpcommand | scp command]].)