dockerTools.buildImage: Preserve environment variables from the parent image

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Utku Demir 2020-05-08 21:49:16 +12:00
parent d78ba41a56
commit f5a90a7aab
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3 changed files with 48 additions and 6 deletions

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@ -124,6 +124,16 @@ import ./make-test-python.nix ({ pkgs, ... }: {
f"docker run --rm ${examples.layersOrder.imageName} cat /tmp/layer{index}"
)
with subtest("Ensure environment variables are correctly inherited"):
docker.succeed(
"docker load --input='${examples.environmentVariables}'"
)
out = docker.succeed("docker run --rm ${examples.environmentVariables.imageName} env")
env = out.splitlines()
assert "FROM_PARENT=true" in env, "envvars from the parent should be preserved"
assert "FROM_CHILD=true" in env, "envvars from the child should be preserved"
assert "LAST_LAYER=child" in env, "envvars from the child should take priority"
with subtest("Ensure image with only 2 layers can be loaded"):
docker.succeed(
"docker load --input='${examples.two-layered-image}'"

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@ -773,13 +773,17 @@ rec {
mkdir image
touch baseFiles
baseEnvs='[]'
if [[ -n "$fromImage" ]]; then
echo "Unpacking base image..."
tar -C image -xpf "$fromImage"
# Store the layers and the environment variables from the base image
cat ./image/manifest.json | jq -r '.[0].Layers | .[]' > layer-list
configName="$(cat ./image/manifest.json | jq -r '.[0].Config')"
baseEnvs="$(cat "./image/$configName" | jq '.config.Env // []')"
# Do not import the base image configuration and manifest
# Otherwise do not import the base image configuration and manifest
chmod a+w image image/*.json
rm -f image/*.json
@ -859,7 +863,8 @@ rec {
) | sponge layer-list
# Create image json and image manifest
imageJson=$(cat ${baseJson} | jq ". + {\"rootfs\": {\"diff_ids\": [], \"type\": \"layers\"}}")
imageJson=$(cat ${baseJson} | jq '.config.Env = $baseenv + .config.Env' --argjson baseenv "$baseEnvs")
imageJson=$(echo "$imageJson" | jq ". + {\"rootfs\": {\"diff_ids\": [], \"type\": \"layers\"}}")
manifestJson=$(jq -n "[{\"RepoTags\":[\"$imageName:$imageTag\"]}]")
for layerTar in $(cat ./layer-list); do

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@ -231,14 +231,41 @@ rec {
'';
};
# 14. Create another layered image, for comparing layers with image 10.
# 14. Environment variable inheritance.
# Child image should inherit parents environment variables,
# optionally overriding them.
environmentVariables = let
parent = pkgs.dockerTools.buildImage {
name = "parent";
tag = "latest";
config = {
Env = [
"FROM_PARENT=true"
"LAST_LAYER=parent"
];
};
};
in pkgs.dockerTools.buildImage {
name = "child";
fromImage = parent;
tag = "latest";
contents = [ pkgs.coreutils ];
config = {
Env = [
"FROM_CHILD=true"
"LAST_LAYER=child"
];
};
};
# 15. Create another layered image, for comparing layers with image 10.
another-layered-image = pkgs.dockerTools.buildLayeredImage {
name = "another-layered-image";
tag = "latest";
config.Cmd = [ "${pkgs.hello}/bin/hello" ];
};
# 15. Create a layered image with only 2 layers
# 16. Create a layered image with only 2 layers
two-layered-image = pkgs.dockerTools.buildLayeredImage {
name = "two-layered-image";
tag = "latest";
@ -247,7 +274,7 @@ rec {
maxLayers = 2;
};
# 16. Create a layered image with more packages than max layers.
# 17. Create a layered image with more packages than max layers.
# coreutils and hello are part of the same layer
bulk-layer = pkgs.dockerTools.buildLayeredImage {
name = "bulk-layer";
@ -258,7 +285,7 @@ rec {
maxLayers = 2;
};
# 17. Create a "layered" image without nix store layers. This is not
# 18. Create a "layered" image without nix store layers. This is not
# recommended, but can be useful for base images in rare cases.
no-store-paths = pkgs.dockerTools.buildLayeredImage {
name = "no-store-paths";