// 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
}
// For targets that have post-build functions, we have to store and retrieve the target's
// output to feed to it
func loadPostBuildOutput(state *core.BuildState, target *core.BuildTarget) string {
// Normally filegroups don't have post-build functions, but we use this sometimes for testing.
if target.IsFilegroup() {
return ""
}
out, err := ioutil.ReadFile(postBuildOutputFileName(target))
if err != nil {
panic(err)
}
return string(out)
}