// Builds a single target
func buildTarget(tid int, state *core.BuildState, target *core.BuildTarget) (err error) {
defer func() {
if r := recover(); r != nil {
if e, ok := r.(error); ok {
err = e
} else {
err = fmt.Errorf("%s", r)
}
}
}()
if err := target.CheckDependencyVisibility(state.Graph); err != nil {
return err
}
// We can't do this check until build time, until then we don't know what all the outputs
// will be (eg. for filegroups that collect outputs of other rules).
if err := target.CheckDuplicateOutputs(); err != nil {
return err
}
// This must run before we can leave this function successfully by any path.
if target.PreBuildFunction != 0 {
log.Debug("Running pre-build function for %s", target.Label)
if err := parse.RunPreBuildFunction(tid, state, target); err != nil {
return err
}
log.Debug("Finished pre-build function for %s", target.Label)
}
state.LogBuildResult(tid, target.Label, core.TargetBuilding, "Preparing...")
var postBuildOutput string
if state.PrepareOnly && state.IsOriginalTarget(target.Label) {
if target.IsFilegroup() {
return fmt.Errorf("Filegroup targets don't have temporary directories")
}
if err := prepareDirectories(target); err != nil {
return err
}
if err := prepareSources(state.Graph, target); err != nil {
return err
}
return stopTarget
}
if !needsBuilding(state, target, false) {
log.Debug("Not rebuilding %s, nothing's changed", target.Label)
postBuildOutput = runPostBuildFunctionIfNeeded(tid, state, target)
// If a post-build function ran it may modify the rule definition. In that case we
// need to check again whether the rule needs building.
if target.PostBuildFunction == 0 || !needsBuilding(state, target, true) {
target.SetState(core.Reused)
state.LogBuildResult(tid, target.Label, core.TargetCached, "Unchanged")
return nil // Nothing needs to be done.
} else {
log.Debug("Rebuilding %s after post-build function", target.Label)
}
}
if target.IsFilegroup() {
log.Debug("Building %s...", target.Label)
return buildFilegroup(tid, state, target)
}
oldOutputHash, outputHashErr := OutputHash(target)
if err := prepareDirectories(target); err != nil {
return fmt.Errorf("Error preparing directories for %s: %s", target.Label, err)
}
retrieveArtifacts := func() bool {
state.LogBuildResult(tid, target.Label, core.TargetBuilding, "Checking cache...")
if _, retrieved := retrieveFromCache(state, target); retrieved {
log.Debug("Retrieved artifacts for %s from cache", target.Label)
checkLicences(state, target)
newOutputHash, err := calculateAndCheckRuleHash(state, target)
if err != nil { // Most likely hash verification failure
log.Warning("Error retrieving cached artifacts for %s: %s", target.Label, err)
RemoveOutputs(target)
return false
} else if outputHashErr != nil || !bytes.Equal(oldOutputHash, newOutputHash) {
target.SetState(core.Cached)
state.LogBuildResult(tid, target.Label, core.TargetCached, "Cached")
} else {
target.SetState(core.Unchanged)
state.LogBuildResult(tid, target.Label, core.TargetCached, "Cached (unchanged)")
}
return true // got from cache
}
return false
}
cacheKey := mustShortTargetHash(state, target)
if state.Cache != nil {
// Note that ordering here is quite sensitive since the post-build function can modify
// what we would retrieve from the cache.
if target.PostBuildFunction != 0 {
log.Debug("Checking for post-build output file for %s in cache...", target.Label)
if (*state.Cache).RetrieveExtra(target, cacheKey, core.PostBuildOutputFileName(target)) {
postBuildOutput = runPostBuildFunctionIfNeeded(tid, state, target)
if retrieveArtifacts() {
return nil
}
}
} else if retrieveArtifacts() {
return nil
}
}
if err := prepareSources(state.Graph, target); err != nil {
return fmt.Errorf("Error preparing sources for %s: %s", target.Label, err)
}
state.LogBuildResult(tid, target.Label, core.TargetBuilding, target.BuildingDescription)
replacedCmd := replaceSequences(target)
env := core.StampedBuildEnvironment(state, target, false, cacheKey)
log.Debug("Building target %s\nENVIRONMENT:\n%s\n%s", target.Label, strings.Join(env, "\n"), replacedCmd)
out, combined, err := core.ExecWithTimeoutShell(target.TmpDir(), env, target.BuildTimeout, state.Config.Build.Timeout, state.ShowAllOutput, replacedCmd)
if err != nil {
if state.Verbosity >= 4 {
return fmt.Errorf("Error building target %s: %s\nENVIRONMENT:\n%s\n%s\n%s",
target.Label, err, strings.Join(env, "\n"), target.GetCommand(), combined)
}
return fmt.Errorf("Error building target %s: %s\n%s", target.Label, err, combined)
}
if target.PostBuildFunction != 0 {
out = bytes.TrimSpace(out)
sout := string(out)
if postBuildOutput != "" {
// We've already run the post-build function once, it's not safe to do it again (e.g. if adding new
// targets, it will likely fail). Theoretically it should get the same output this time and hence would
// do the same thing, since it had all the same inputs.
// Obviously we can't be 100% sure that will be the case, so issue a warning if not...
if postBuildOutput != sout {
log.Warning("The build output for %s differs from what we got back from the cache earlier.\n"+
"This implies your target's output is nondeterministic; Please won't re-run the\n"+
"post-build function, which will *probably* be okay, but Please can't be sure.\n"+
"See https://github.com/thought-machine/please/issues/113 for more information.", target.Label)
log.Debug("Cached build output for %s: %s\n\nNew build output: %s",
target.Label, postBuildOutput, sout)
}
} else if err := parse.RunPostBuildFunction(tid, state, target, sout); err != nil {
return err
}
storePostBuildOutput(state, target, out)
}
checkLicences(state, target)
state.LogBuildResult(tid, target.Label, core.TargetBuilding, "Collecting outputs...")
extraOuts, outputsChanged, err := moveOutputs(state, target)
if err != nil {
return fmt.Errorf("Error moving outputs for target %s: %s", target.Label, err)
}
if _, err = calculateAndCheckRuleHash(state, target); err != nil {
return err
}
if outputsChanged {
target.SetState(core.Built)
} else {
target.SetState(core.Unchanged)
}
if state.Cache != nil {
state.LogBuildResult(tid, target.Label, core.TargetBuilding, "Storing...")
newCacheKey := mustShortTargetHash(state, target)
(*state.Cache).Store(target, newCacheKey)
if target.PostBuildFunction != 0 {
// NB. Important this is stored with the earlier hash - if we calculate the hash
// now, it might be different, and we could of course never retrieve it again.
(*state.Cache).StoreExtra(target, cacheKey, core.PostBuildOutputFileName(target))
}
for _, out := range extraOuts {
(*state.Cache).StoreExtra(target, newCacheKey, out)
}
}
// Clean up the temporary directory once it's done.
if state.CleanWorkdirs {
if err := os.RemoveAll(target.TmpDir()); err != nil {
log.Warning("Failed to remove temporary directory for %s: %s", target.Label, err)
}
}
if outputsChanged {
state.LogBuildResult(tid, target.Label, core.TargetBuilt, "Built")
} else {
state.LogBuildResult(tid, target.Label, core.TargetBuilt, "Built (unchanged)")
}
return nil
}
// Return true if the rule needs building, false if the existing outputs are OK.
func needsBuilding(state *core.BuildState, target *core.BuildTarget, postBuild bool) bool {
// Check the dependencies first, because they don't need any disk I/O.
if target.NeedsTransitiveDependencies {
if anyDependencyHasChanged(target) {
return true // one of the transitive deps has changed, need to rebuild
}
} else {
for _, dep := range target.Dependencies() {
if dep.State() < core.Unchanged {
log.Debug("Need to rebuild %s, %s has changed", target.Label, dep.Label)
return true // dependency has just been rebuilt, do this too.
}
}
}
oldRuleHash, oldConfigHash, oldSourceHash := readRuleHashFile(ruleHashFileName(target), postBuild)
if !bytes.Equal(oldConfigHash, state.Hashes.Config) {
if len(oldConfigHash) == 0 {
// Small nicety to make it a bit clearer what's going on.
log.Debug("Need to build %s, outputs aren't there", target.Label)
} else {
log.Debug("Need to rebuild %s, config has changed (was %s, need %s)", target.Label, b64(oldConfigHash), b64(state.Hashes.Config))
}
return true
}
newRuleHash := RuleHash(target, false, postBuild)
if !bytes.Equal(oldRuleHash, newRuleHash) {
log.Debug("Need to rebuild %s, rule has changed (was %s, need %s)", target.Label, b64(oldRuleHash), b64(newRuleHash))
return true
}
newSourceHash, err := sourceHash(state.Graph, target)
if err != nil || !bytes.Equal(oldSourceHash, newSourceHash) {
log.Debug("Need to rebuild %s, sources have changed (was %s, need %s)", target.Label, b64(oldSourceHash), b64(newSourceHash))
return true
}
// Check the outputs of this rule exist. This would only happen if the user had
// removed them but it's incredibly aggravating if you remove an output and the
// rule won't rebuild itself.
for _, output := range target.Outputs() {
realOutput := path.Join(target.OutDir(), output)
if !core.PathExists(realOutput) {
log.Debug("Output %s doesn't exist for rule %s; will rebuild.", realOutput, target.Label)
return true
}
}
// Maybe we've forced a rebuild. Do this last; might be interesting to see if it needed building anyway.
return state.ForceRebuild && (state.IsOriginalTarget(target.Label) || state.IsOriginalTarget(target.Label.Parent()))
}
// calculateAndCheckRuleHash checks the output hash for a rule.
func calculateAndCheckRuleHash(state *core.BuildState, target *core.BuildTarget) ([]byte, error) {
hash, err := OutputHash(target)
if err != nil {
return nil, err
}
if err = checkRuleHashes(target, hash); err != nil {
if state.NeedHashesOnly && (state.IsOriginalTarget(target.Label) || state.IsOriginalTarget(target.Label.Parent())) {
return nil, stopTarget
} else if state.VerifyHashes {
return nil, err
} else {
log.Warning("%s", err)
}
}
if err := writeRuleHashFile(state, target); err != nil {
return nil, fmt.Errorf("Attempting to create hash file: %s", err)
}
return hash, nil
}