diff --git a/doc/functions.xml b/doc/functions.xml index 3cfc6884bd26..31b40fb084a3 100644 --- a/doc/functions.xml +++ b/doc/functions.xml @@ -638,6 +638,45 @@ buildImage { pkgs.cacert to contents. + + + Impurely Defining a Docker Layer's Creation Date + + Because dates are an impurity, by default + buildImage will use a static date of one + second past the UNIX Epoch. This can be a bit frustrating when + listing docker images in the CLI: + + + + If you want to trade the purity for a better user experience, + you can set created to + now. + + + + and now the Docker CLI will display a reasonable date and + sort the images as expected: + + +
diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix index 93b715659eb0..0cee1dd2916f 100644 --- a/pkgs/build-support/docker/default.nix +++ b/pkgs/build-support/docker/default.nix @@ -450,11 +450,18 @@ rec { baseName = baseNameOf name; # Create a JSON blob of the configuration. Set the date to unix zero. - baseJson = writeText "${baseName}-config.json" (builtins.toJSON { - inherit created config; - architecture = "amd64"; - os = "linux"; - }); + baseJson = let + pure = writeText "${baseName}-config.json" (builtins.toJSON { + inherit created config; + architecture = "amd64"; + os = "linux"; + }); + impure = runCommand "${baseName}-config.json" + { buildInputs = [ jq ]; } + '' + jq ".created = \"$(TZ=utc date --iso-8601="seconds")\"" ${pure} > $out + ''; + in if created == "now" then impure else pure; layer = if runAsRoot == null @@ -577,7 +584,7 @@ rec { currentID=$layerID while [[ -n "$currentID" ]]; do layerChecksum=$(sha256sum image/$currentID/layer.tar | cut -d ' ' -f1) - imageJson=$(echo "$imageJson" | jq ".history |= [{\"created\": \"${created}\"}] + .") + imageJson=$(echo "$imageJson" | jq ".history |= [{\"created\": \"$(jq -r .created ${baseJson})\"}] + .") imageJson=$(echo "$imageJson" | jq ".rootfs.diff_ids |= [\"sha256:$layerChecksum\"] + .") manifestJson=$(echo "$manifestJson" | jq ".[0].Layers |= [\"$currentID/layer.tar\"] + .")