diff options
Diffstat (limited to 'pkgs/build-support/docker/default.nix')
| -rw-r--r-- | pkgs/build-support/docker/default.nix | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix index fec289f0ff1..a73737cb123 100644 --- a/pkgs/build-support/docker/default.nix +++ b/pkgs/build-support/docker/default.nix @@ -729,6 +729,8 @@ rec { name, # Image tag, the Nix's output hash will be used if null tag ? null, + # Parent image, to append to. + fromImage ? null, # Files to put on the image (a nix store path or list of paths). contents ? [], # Docker config; e.g. what command to run on the container. @@ -791,7 +793,7 @@ rec { unnecessaryDrvs = [ baseJson overallClosure ]; conf = runCommand "${baseName}-conf.json" { - inherit maxLayers created; + inherit fromImage maxLayers created; imageName = lib.toLower name; passthru.imageTag = if tag != null @@ -821,6 +823,27 @@ rec { unnecessaryDrvs} } + # Compute the number of layers that are already used by a potential + # 'fromImage' as well as the customization layer. Ensure that there is + # still at least one layer available to store the image contents. + usedLayers=0 + + # subtract number of base image layers + if [[ -n "$fromImage" ]]; then + (( usedLayers += $(tar -xOf "$fromImage" manifest.json | jq '.[0].Layers | length') )) + fi + + # one layer will be taken up by the customisation layer + (( usedLayers += 1 )) + + if ! (( $usedLayers < $maxLayers )); then + echo >&2 "Error: usedLayers $usedLayers layers to store 'fromImage' and" \ + "'extraCommands', but only maxLayers=$maxLayers were" \ + "allowed. At least 1 layer is required to store contents." + exit 1 + fi + availableLayers=$(( maxLayers - usedLayers )) + # Create $maxLayers worth of Docker Layers, one layer per store path # unless there are more paths than $maxLayers. In that case, create # $maxLayers-1 for the most popular layers, and smush the remainaing @@ -838,18 +861,20 @@ rec { | (.[:$maxLayers-1] | map([.])) + [ .[$maxLayers-1:] ] | map(select(length > 0)) ' \ - --argjson maxLayers "$(( maxLayers - 1 ))" # one layer will be taken up by the customisation layer + --argjson maxLayers "$availableLayers" )" cat ${baseJson} | jq ' . + { "store_dir": $store_dir, + "from_image": $from_image, "store_layers": $store_layers, "customisation_layer", $customisation_layer, "repo_tag": $repo_tag, "created": $created } ' --arg store_dir "${storeDir}" \ + --argjson from_image ${if fromImage == null then "null" else "'\"${fromImage}\"'"} \ --argjson store_layers "$store_layers" \ --arg customisation_layer ${customisationLayer} \ --arg repo_tag "$imageName:$imageTag" \ |