Example #1
1
// 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
}