Files
helmfile/pkg/app/desired_state_file_loader.go
T
Dominik Schmidt 0139304d97 feat(state): add mergeStrategy: fallback for first-file-wins env values (#2578)
* feat(state): add mergeStrategy field to EnvironmentSpec

Introduces a per-environment mergeStrategy with valid values "override"
(default, current behavior) and "fallback". This commit only adds the
field, the constants, and a parse-time validator; the loader still
ignores the value, so behavior is unchanged.

Subsequent commits thread the value through the values loader and
implement the fallback semantics.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* refactor(state): thread mergeStrategy through values loader

Adds a mergeStrategy string parameter to LoadEnvironmentValues,
loadValuesEntries, and mapMerge so the value can flow from
EnvironmentSpec down to the merge call site. Behavior is unchanged in
this commit; mapMerge ignores the strategy and the next commit
implements the fallback semantics.

Top-level state.DefaultValues and the --state-values-file/-set loaders
are passed an empty strategy ("") since they have no per-environment
spec to consult and stay on the default override behavior.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* feat(state): implement fallback merge strategy

Adds a hand-rolled fallbackDeepMerge that, unlike mergo, preserves
keys present in the destination even when their value is the zero
value (false, 0, "", nil, empty list/map). mapMerge dispatches to it
when mergeStrategy == "fallback"; "override" and the empty default
keep using mergo with WithOverride so existing behaviour is unchanged.

Validation lives at the entry of LoadEnvironmentValues so a single
chokepoint guards the field. Invalid values produce an error naming
both the offending value and the valid options.

Tests cover: first-file-wins precedence, gap filling, deep nested
merge, three-file chains, explicit zero-value preservation (the case
naïve mergo gets wrong), explicit nil preservation, inline map
entries, override regression, default-equals-override equivalence,
and invalid-strategy errors.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* feat(state): expose prior-file values in fallback template context

Under mergeStrategy: fallback, .gotmpl values files can now reference
values from earlier files in the same `values:` list via .Values
(e.g. `service.domain: "service.{{ .Values.cluster.domain }}"`).

The accumulated result is layered under env.GetMergedValues so env
defaults, env values, and CLI overrides still win on overlap. Override
mode keeps the historical template context — unchanged — so this is
strictly opt-in via the mergeStrategy field.

Together with the precedence flip from the previous commit, this lets
users replace the brittle two-stage `merged-values.yaml.gotmpl`
workaround with native helmfile syntax.

Tests cover the headline cross-file template reference case and pin
the override-mode contract that prior-file values stay invisible.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* docs: document mergeStrategy and fallback semantics

Adds a new section to values-and-merging.md describing the override vs
fallback strategies, the explicit-zero-value preservation guarantee,
and the cross-file template reference behavior. Adds a brief pointer
to environments.md so users land on the new field from the
environment values discussion.

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

* refactor(state): reuse maputil.MergeMaps for fallback merge

Replaces the hand-rolled fallbackDeepMerge with a single call to
maputil.MergeMaps, swapping its arguments so the accumulated dest wins
over the new src file. Same first-file-wins semantic, fewer lines, and
the fallback path now inherits the same slice merge strategies the
rest of helmfile already uses.

The one observable behavior shift is for explicit nil values: under
fallback, nil in an earlier file no longer 'wins' over a non-nil value
in a later file — instead it falls through (matching MergeMaps' rule
that nil from the override side only fills missing keys). This is
internally consistent: nil-overwrites is an mergo.WithOverride quirk
that lives only in the override path. The renamed test
NilFallsThroughToFallback pins the new behavior with a comment
referencing the contrast with override mode (Issue1154).

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>

---------

Signed-off-by: Dominik Schmidt <dev@dominik-schmidt.de>
2026-05-07 21:50:05 +08:00

341 lines
9.8 KiB
Go

package app
import (
"bytes"
"errors"
"fmt"
"os"
"path/filepath"
"slices"
"dario.cat/mergo"
"github.com/helmfile/vals"
"go.uber.org/zap"
"github.com/helmfile/helmfile/pkg/environment"
"github.com/helmfile/helmfile/pkg/envvar"
"github.com/helmfile/helmfile/pkg/filesystem"
"github.com/helmfile/helmfile/pkg/helmexec"
"github.com/helmfile/helmfile/pkg/policy"
"github.com/helmfile/helmfile/pkg/remote"
"github.com/helmfile/helmfile/pkg/state"
)
const (
DefaultHelmBinary = state.DefaultHelmBinary
DefaultKustomizeBinary = state.DefaultKustomizeBinary
)
type desiredStateLoader struct {
overrideKubeContext string
overrideHelmBinary string
overrideKustomizeBinary string
enableLiveOutput bool
env string
namespace string
chart string
fs *filesystem.FileSystem
baseDir string // Base directory for resolving relative paths, empty means use cwd
getHelm func(*state.HelmState) (helmexec.Interface, error)
remote *remote.Remote
logger *zap.SugaredLogger
valsRuntime vals.Evaluator
lockFilePath string
}
func (ld *desiredStateLoader) Load(f string, opts LoadOpts) (*state.HelmState, error) {
var overrodeEnv *environment.Environment
fileArgs := opts.Environment.OverrideValues
setArgs := opts.Environment.OverrideCLISetValues
if len(fileArgs) > 0 || len(setArgs) > 0 {
if opts.CalleePath == "" {
return nil, fmt.Errorf("bug: opts.CalleePath was empty: f=%s, opts=%v", f, opts)
}
storage := state.NewStorage(opts.CalleePath, ld.logger, ld.fs)
envld := state.NewEnvironmentValuesLoader(storage, ld.fs, ld.logger, ld.remote)
handler := state.MissingFileHandlerError
overrodeEnv = &environment.Environment{
Name: ld.env,
Values: map[string]any{},
CLIOverrides: map[string]any{},
}
// --state-values-file: loaded into Values so arrays replace (not merge)
if len(fileArgs) > 0 {
fileVals, err := envld.LoadEnvironmentValues(&handler, fileArgs, environment.New(ld.env), ld.env, "")
if err != nil {
return nil, err
}
overrodeEnv.Values = fileVals
}
// --state-values-set: loaded into CLIOverrides so arrays merge element-by-element
if len(setArgs) > 0 {
setVals, err := envld.LoadEnvironmentValues(&handler, setArgs, environment.New(ld.env), ld.env, "")
if err != nil {
return nil, err
}
overrodeEnv.CLIOverrides = setVals
}
}
// Resolve file path relative to baseDir if provided
var dir, file string
if ld.baseDir != "" {
// If baseDir is set, resolve all paths relative to it
if !filepath.IsAbs(f) {
f = filepath.Join(ld.baseDir, f)
}
dir = filepath.Dir(f)
file = filepath.Base(f)
} else {
// Use original behavior
dir = filepath.Dir(f)
file = filepath.Base(f)
}
st, err := ld.loadFileWithOverrides(nil, overrodeEnv, dir, file, true)
if err != nil {
return nil, err
}
if opts.Reverse {
st.Reverse()
}
if ld.overrideKubeContext != "" {
if st.OverrideKubeContext != "" {
return nil, errors.New("err: Cannot use option --kube-context and set attribute kubeContext.")
}
st.OverrideKubeContext = ld.overrideKubeContext
// HelmDefaults.KubeContext is also overridden in here
// to set default release value properly.
st.HelmDefaults.KubeContext = ld.overrideKubeContext
}
if ld.namespace != "" {
if st.OverrideNamespace != "" {
return nil, errors.New("err: Cannot use option --namespace and set attribute namespace.")
}
st.OverrideNamespace = ld.namespace
}
if ld.chart != "" {
if st.OverrideChart != "" {
return nil, errors.New("err: Cannot use option --chart and set attribute chart.")
}
st.OverrideChart = ld.chart
}
return st, nil
}
func (ld *desiredStateLoader) loadFile(inheritedEnv, overrodeEnv *environment.Environment, baseDir, file string, evaluateBases bool) (*state.HelmState, error) {
path, err := ld.remote.Locate(file, "states")
if err != nil {
return nil, fmt.Errorf("locate: %v", err)
}
if file != path {
ld.logger.Debugf("fetched remote \"%s\" to local cache \"%s\" and loading the latter...", file, path)
}
file = path
return ld.loadFileWithOverrides(inheritedEnv, overrodeEnv, baseDir, file, evaluateBases)
}
func (ld *desiredStateLoader) loadFileWithOverrides(inheritedEnv, overrodeEnv *environment.Environment, baseDir, file string, evaluateBases bool) (*state.HelmState, error) {
var f string
if filepath.IsAbs(file) {
f = file
} else {
f = filepath.Join(baseDir, file)
}
fileBytes, err := ld.fs.ReadFile(f)
if err != nil {
return nil, err
}
self, err := ld.load(
inheritedEnv,
overrodeEnv,
baseDir,
f,
fileBytes,
evaluateBases,
)
if err != nil {
return nil, err
}
for i, h := range self.Helmfiles {
if h.Path == f {
return nil, fmt.Errorf("%s contains a recursion into the same sub-helmfile at helmfiles[%d]", f, i)
}
if h.Path == "." {
return nil, fmt.Errorf("%s contains a recursion into the the directory containing this helmfile at helmfiles[%d]", f, i)
}
}
return self, nil
}
func (a *desiredStateLoader) underlying() *state.StateCreator {
c := state.NewCreator(a.logger, a.fs, a.valsRuntime, a.getHelm, a.overrideHelmBinary, a.overrideKustomizeBinary, a.remote, a.enableLiveOutput, a.lockFilePath)
c.LoadFile = a.loadFile
return c
}
func (a *desiredStateLoader) rawLoad(yaml []byte, baseDir, file string, evaluateBases bool, env, overrodeEnv *environment.Environment) (*state.HelmState, error) {
var st *state.HelmState
var err error
merged, err := env.Merge(overrodeEnv)
if err != nil {
return nil, err
}
// applyDefaults is always false here - defaults are applied after all parts are merged
st, err = a.underlying().ParseAndLoad(yaml, baseDir, file, a.env, false, evaluateBases, false, merged, nil)
if err != nil {
return nil, err
}
helmfiles, err := st.ExpandedHelmfiles()
if err != nil {
return nil, err
}
st.Helmfiles = helmfiles
return st, nil
}
func (ld *desiredStateLoader) load(env, overrodeEnv *environment.Environment, baseDir, filename string, content []byte, evaluateBases bool) (*state.HelmState, error) {
// Allows part-splitting to work with CLRF-ed content
normalizedContent := bytes.ReplaceAll(content, []byte("\r\n"), []byte("\n"))
isStrict, err := policy.Checker(filename, normalizedContent)
if err != nil {
if isStrict {
return nil, err
}
ld.logger.Warnf("WARNING: %v", err)
}
parts := bytes.Split(normalizedContent, []byte("\n---\n"))
hasEnv := env != nil || overrodeEnv != nil
var finalState *state.HelmState
for i, part := range parts {
id := fmt.Sprintf("%s.part.%d", filename, i)
var rawContent []byte
shouldRender := filepath.Ext(filename) == ".gotmpl" || os.Getenv(envvar.RenderYaml) == "true"
if shouldRender {
var yamlBuf *bytes.Buffer
var err error
if env == nil && overrodeEnv == nil {
yamlBuf, err = ld.renderTemplatesToYaml(baseDir, id, part)
if err != nil {
return nil, fmt.Errorf("error during %s parsing: %v", id, err)
}
} else {
yamlBuf, err = ld.renderTemplatesToYamlWithEnv(baseDir, id, part, env, overrodeEnv)
if err != nil {
return nil, fmt.Errorf("error during %s parsing: %v", id, err)
}
}
rawContent = yamlBuf.Bytes()
} else {
rawContent = part
}
currentState, err := ld.rawLoad(
rawContent,
baseDir,
filename,
evaluateBases,
env,
overrodeEnv,
)
if err != nil {
return nil, err
}
if finalState == nil {
finalState = currentState
} else {
if err := mergo.Merge(&finalState.ReleaseSetSpec, &currentState.ReleaseSetSpec, mergo.WithOverride); err != nil {
return nil, err
}
finalState.RenderedValues = currentState.RenderedValues
}
env = &finalState.Env
ld.logger.Debugf("merged environment: %v", env)
if len(finalState.Environments) == 0 {
continue
}
// At this point, we are sure that the env has been
// read from the vanilla or rendered YAML document.
// We can now check if the env is defined in it and fail accordingly.
// See https://github.com/helmfile/helmfile/issues/913
// We defer the missing env detection and failure until
// all the helmfile parts are loaded and merged.
// Otherwise, any single helmfile part missing the env would fail the whole helmfile run.
// That's problematic, because each helmfile part is supposed to be incomplete, and
// they become complete only after merging all the parts.
// See https://github.com/helmfile/helmfile/issues/807 for the rationale of this.
if _, ok := finalState.Environments[env.Name]; evaluateBases && env.Name != state.DefaultEnv && !ok {
return nil, &state.StateLoadError{
Msg: fmt.Sprintf("failed to read %s", finalState.FilePath),
Cause: &state.UndefinedEnvError{Env: env.Name},
}
}
}
// After all parts are merged, apply defaults and overrides to ensure
// that values from earlier parts (like helmBinary) are preserved correctly
// in the merged state.
// See https://github.com/helmfile/helmfile/issues/2319
if evaluateBases {
ld.underlying().ApplyDefaultsAndOverrides(finalState)
}
// If environments are not defined in the helmfile at all although the env is specified,
// it's a missing env situation. Let's fail.
if len(finalState.Environments) == 0 && evaluateBases && !hasEnv && env.Name != state.DefaultEnv {
return nil, &state.StateLoadError{
Msg: fmt.Sprintf("failed to read %s", finalState.FilePath),
Cause: &state.UndefinedEnvError{Env: env.Name},
}
}
// Validate updateStrategy value if set in the releases
for i := range finalState.Releases {
if finalState.Releases[i].UpdateStrategy != "" {
if !slices.Contains(state.ValidUpdateStrategyValues, finalState.Releases[i].UpdateStrategy) {
return nil, &state.StateLoadError{
Msg: fmt.Sprintf("failed to read %s", finalState.FilePath),
Cause: &state.InvalidUpdateStrategyError{UpdateStrategy: finalState.Releases[i].UpdateStrategy},
}
}
}
}
finalState.OrginReleases = finalState.Releases
return finalState, nil
}