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fix: reuse only user-supplied values when no values flag is given (#464) #1087

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fix: reuse only user-supplied values when no values flag is given (#464) #1087

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17 changes: 14 additions & 3 deletions cmd/helm.go
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Original file line number Diff line number Diff line change
Expand Up @@ -214,7 +214,7 @@ func (d *diffCmd) template(isUpgrade bool) ([]byte, error) {
if d.insecureSkipTLSVerify {
flags = append(flags, "--insecure-skip-tls-verify")
}
// Helm automatically enable --reuse-values when there's no --set, --set-string, --set-json, --set-values, --set-file present.
// Helm automatically reuses the user-supplied values of the last release when there's no --set, --set-string, --set-json, --set-values, --set-file present.
// Let's simulate that in helm-diff.
// See https://medium.com/@kcatstack/understand-helm-upgrade-flags-reset-values-reuse-values-6e58ac8f127e
shouldDefaultReusingValues := len(d.values) == 0 && len(d.stringValues) == 0 && len(d.stringLiteralValues) == 0 && len(d.jsonValues) == 0 && len(d.valueFiles) == 0 && len(d.fileValues) == 0
Expand All @@ -240,12 +240,23 @@ func (d *diffCmd) template(isUpgrade bool) ([]byte, error) {
}
err = d.writeExistingValues(tmpfile, false)
} else {
err = d.writeExistingValues(tmpfile, true)
// Only --reuse-values also reuses the values of the chart that the release was installed from.
// By default, Helm reuses just the user-supplied values, so that changes to the values.yaml
// of the chart take effect. See https://github.com/databus23/helm-diff/issues/464
err = d.writeExistingValues(tmpfile, d.reuseValues)
}
if err != nil {
return nil, err
}
flags = append(flags, "--values", tmpfile.Name())
existingValues, err := os.ReadFile(tmpfile.Name())
if err != nil {
return nil, err
}
// `helm get values` prints "null" for a release without user-supplied values.
// There is nothing to reuse then.
if v := bytes.TrimSpace(existingValues); len(v) > 0 && !bytes.Equal(v, []byte("null")) {
flags = append(flags, "--values", tmpfile.Name())
}
}
for _, value := range d.values {
flags = append(flags, "--set", value)
Expand Down
7 changes: 6 additions & 1 deletion cmd/main_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -32,13 +32,18 @@ func printFakeHelmVersion() {
}

// printFakeHelmOutput prints the output for a fake helm invocation.
// A `helm version` call prints helm version build info; any other
// A `helm version` call prints helm version build info; a `helm get values`
// call prints HELM_DIFF_FAKE_VALUES_OUTPUT if that is set; any other
// invocation prints HELM_DIFF_FAKE_OUTPUT.
func printFakeHelmOutput() {
if len(os.Args) > 1 && os.Args[1] == "version" {
printFakeHelmVersion()
return
}
if v, ok := os.LookupEnv("HELM_DIFF_FAKE_VALUES_OUTPUT"); ok && len(os.Args) > 2 && os.Args[1] == "get" && os.Args[2] == "values" {
fmt.Print(v)
return
}
fmt.Print(os.Getenv("HELM_DIFF_FAKE_OUTPUT"))
}

Expand Down
39 changes: 35 additions & 4 deletions cmd/upgrade_test.go
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Expand Up @@ -401,35 +401,60 @@ data:
fakeHelmMode string
args []string
useUpgradeDryRun bool
// existingValues is what `helm get values` prints for an existing release.
// Empty means that it prints the manifest, which stands in for some values.
existingValues string
// wantGetValues is the expected `helm get values` call.
// Empty means that the values must not be fetched at all.
wantGetValues string
// wantValues is whether the fetched values must be passed on with --values.
wantValues bool
}{
{
name: "existing release with --reuse-values",
fakeHelmMode: "capture_args",
args: []string{"--reuse-values"},
wantGetValues: "get values my-release --output yaml --all --namespace prod-apps\n",
wantValues: true,
},
{
name: "existing release with --reset-then-reuse-values",
fakeHelmMode: "capture_args",
args: []string{"--reset-then-reuse-values"},
wantGetValues: "get values my-release --output yaml --namespace prod-apps\n",
wantValues: true,
},
{
name: "existing release with --install --reuse-values",
fakeHelmMode: "capture_args",
args: []string{"--install", "--reuse-values"},
wantGetValues: "get values my-release --output yaml --all --namespace prod-apps\n",
wantValues: true,
},
{
// Helm enables --reuse-values by default when there is no --set, --set-string,
// --set-literal, --set-json, --values or --set-file flag, so the values of an
// existing release are fetched even without any of the reuse flags.
// Helm reuses the user-supplied values of an existing release when there is no
// --set, --set-string, --set-literal, --set-json, --values or --set-file flag.
// Unlike with --reuse-values, the values of the chart that the release was installed
// from are not reused, so the values are fetched without --all.
// See https://github.com/databus23/helm-diff/issues/464
name: "existing release without value flags",
fakeHelmMode: "capture_args",
wantGetValues: "get values my-release --output yaml --all --namespace prod-apps\n",
wantGetValues: "get values my-release --output yaml --namespace prod-apps\n",
wantValues: true,
},
{
name: "existing release without value flags and HELM_DIFF_USE_UPGRADE_DRY_RUN",
fakeHelmMode: "capture_args",
useUpgradeDryRun: true,
wantGetValues: "get values my-release --output yaml --namespace prod-apps\n",
wantValues: true,
},
{
// `helm get values` prints "null" for a release without user-supplied values.
name: "existing release without value flags and without user-supplied values",
fakeHelmMode: "capture_args",
existingValues: "null\n",
wantGetValues: "get values my-release --output yaml --namespace prod-apps\n",
},
{
name: "unreleased with --install",
Expand Down Expand Up @@ -468,6 +493,9 @@ data:
t.Run(tc.name, func(t *testing.T) {
argsFile := t.TempDir() + "/args"
setupFakeHelm(t, tc.fakeHelmMode, manifestYAML, argsFile, "")
if tc.existingValues != "" {
t.Setenv("HELM_DIFF_FAKE_VALUES_OUTPUT", tc.existingValues)
}
renderSubcmd := "template"
if tc.useUpgradeDryRun {
t.Setenv("HELM_DIFF_USE_UPGRADE_DRY_RUN", "true")
Expand Down Expand Up @@ -499,6 +527,9 @@ data:
} else if !strings.Contains(argsContent, tc.wantGetValues) {
t.Errorf("expected 'helm %s', got:\n%s", strings.TrimSpace(tc.wantGetValues), argsContent)
}
if strings.Contains(argsContent, " --values ") != tc.wantValues {
t.Errorf("expected the existing values to be passed with --values: %t, got:\n%s", tc.wantValues, argsContent)
}
})
}
}
Expand Down
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