com.google.gerrit.server.rules.PrologRuleEvaluator Maven / Gradle / Ivy
// Copyright (C) 2012 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.server.rules;
import static com.google.gerrit.server.project.SubmitRuleEvaluator.createRuleError;
import static com.google.gerrit.server.project.SubmitRuleEvaluator.defaultRuleError;
import static com.google.gerrit.server.project.SubmitRuleEvaluator.defaultTypeError;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.CharMatcher;
import com.google.common.flogger.FluentLogger;
import com.google.gerrit.common.data.LabelType;
import com.google.gerrit.common.data.SubmitRecord;
import com.google.gerrit.common.data.SubmitTypeRecord;
import com.google.gerrit.extensions.client.SubmitType;
import com.google.gerrit.reviewdb.client.Account;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.server.account.AccountCache;
import com.google.gerrit.server.account.Accounts;
import com.google.gerrit.server.account.Emails;
import com.google.gerrit.server.project.NoSuchProjectException;
import com.google.gerrit.server.project.ProjectCache;
import com.google.gerrit.server.project.ProjectState;
import com.google.gerrit.server.project.RuleEvalException;
import com.google.gerrit.server.project.SubmitRuleOptions;
import com.google.gerrit.server.query.change.ChangeData;
import com.google.gwtorm.server.OrmException;
import com.google.inject.assistedinject.Assisted;
import com.google.inject.assistedinject.AssistedInject;
import com.googlecode.prolog_cafe.exceptions.CompileException;
import com.googlecode.prolog_cafe.exceptions.ReductionLimitException;
import com.googlecode.prolog_cafe.lang.IntegerTerm;
import com.googlecode.prolog_cafe.lang.ListTerm;
import com.googlecode.prolog_cafe.lang.Prolog;
import com.googlecode.prolog_cafe.lang.PrologMachineCopy;
import com.googlecode.prolog_cafe.lang.StructureTerm;
import com.googlecode.prolog_cafe.lang.SymbolTerm;
import com.googlecode.prolog_cafe.lang.Term;
import com.googlecode.prolog_cafe.lang.VariableTerm;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* Evaluates a submit-like Prolog rule found in the rules.pl file of the current project and filters
* the results through rules found in the parent projects, all the way up to All-Projects.
*/
public class PrologRuleEvaluator {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
/**
* List of characters to allow in the label name, when an invalid name is used. Dash is allowed as
* it can't be the first character: we use a prefix.
*/
private static final CharMatcher VALID_LABEL_MATCHER =
CharMatcher.is('-')
.or(CharMatcher.inRange('a', 'z'))
.or(CharMatcher.inRange('A', 'Z'))
.or(CharMatcher.inRange('0', '9'));
public interface Factory {
/** Returns a new {@link PrologRuleEvaluator} with the specified options */
PrologRuleEvaluator create(ChangeData cd, SubmitRuleOptions options);
}
/**
* Exception thrown when the label term of a submit record unexpectedly didn't contain a user
* term.
*/
private static class UserTermExpected extends Exception {
private static final long serialVersionUID = 1L;
UserTermExpected(SubmitRecord.Label label) {
super(String.format("A label with the status %s must contain a user.", label.toString()));
}
}
private final AccountCache accountCache;
private final Accounts accounts;
private final Emails emails;
private final RulesCache rulesCache;
private final PrologEnvironment.Factory envFactory;
private final ChangeData cd;
private final ProjectState projectState;
private final SubmitRuleOptions opts;
private Term submitRule;
@AssistedInject
private PrologRuleEvaluator(
AccountCache accountCache,
Accounts accounts,
Emails emails,
RulesCache rulesCache,
PrologEnvironment.Factory envFactory,
ProjectCache projectCache,
@Assisted ChangeData cd,
@Assisted SubmitRuleOptions options) {
this.accountCache = accountCache;
this.accounts = accounts;
this.emails = emails;
this.rulesCache = rulesCache;
this.envFactory = envFactory;
this.cd = cd;
this.opts = options;
this.projectState = projectCache.get(cd.project());
}
private static Term toListTerm(List terms) {
Term list = Prolog.Nil;
for (int i = terms.size() - 1; i >= 0; i--) {
list = new ListTerm(terms.get(i), list);
}
return list;
}
private static boolean isUser(Term who) {
return who instanceof StructureTerm
&& who.arity() == 1
&& who.name().equals("user")
&& who.arg(0) instanceof IntegerTerm;
}
private Term getSubmitRule() {
return submitRule;
}
/**
* Evaluate the submit rules.
*
* @return List of {@link SubmitRecord} objects returned from the evaluated rules, including any
* errors.
*/
public Collection evaluate() {
Change change;
try {
change = cd.change();
if (change == null) {
throw new OrmException("No change found");
}
if (projectState == null) {
throw new NoSuchProjectException(cd.project());
}
} catch (OrmException | NoSuchProjectException e) {
return ruleError("Error looking up change " + cd.getId(), e);
}
if (!opts.allowClosed() && change.getStatus().isClosed()) {
SubmitRecord rec = new SubmitRecord();
rec.status = SubmitRecord.Status.CLOSED;
return Collections.singletonList(rec);
}
List results;
try {
results =
evaluateImpl(
"locate_submit_rule", "can_submit", "locate_submit_filter", "filter_submit_results");
} catch (RuleEvalException e) {
return ruleError(e.getMessage(), e);
}
if (results.isEmpty()) {
// This should never occur. A well written submit rule will always produce
// at least one result informing the caller of the labels that are
// required for this change to be submittable. Each label will indicate
// whether or not that is actually possible given the permissions.
return ruleError(
String.format(
"Submit rule '%s' for change %s of %s has no solution.",
getSubmitRuleName(), cd.getId(), projectState.getName()));
}
return resultsToSubmitRecord(getSubmitRule(), results);
}
private String getSubmitRuleName() {
return submitRule == null ? "" : submitRule.name();
}
/**
* Convert the results from Prolog Cafe's format to Gerrit's common format.
*
* can_submit/1 terminates when an ok(P) record is found. Therefore walk the results backwards,
* using only that ok(P) record if it exists. This skips partial results that occur early in the
* output. Later after the loop the out collection is reversed to restore it to the original
* ordering.
*/
public List resultsToSubmitRecord(Term submitRule, List results) {
boolean foundOk = false;
List out = new ArrayList<>(results.size());
for (int resultIdx = results.size() - 1; 0 <= resultIdx; resultIdx--) {
Term submitRecord = results.get(resultIdx);
SubmitRecord rec = new SubmitRecord();
out.add(rec);
if (!(submitRecord instanceof StructureTerm) || 1 != submitRecord.arity()) {
return invalidResult(submitRule, submitRecord);
}
if ("ok".equals(submitRecord.name())) {
rec.status = SubmitRecord.Status.OK;
} else if ("not_ready".equals(submitRecord.name())) {
rec.status = SubmitRecord.Status.NOT_READY;
} else {
return invalidResult(submitRule, submitRecord);
}
// Unpack the one argument. This should also be a structure with one
// argument per label that needs to be reported on to the caller.
//
submitRecord = submitRecord.arg(0);
if (!(submitRecord instanceof StructureTerm)) {
return invalidResult(submitRule, submitRecord);
}
rec.labels = new ArrayList<>(submitRecord.arity());
for (Term state : ((StructureTerm) submitRecord).args()) {
if (!(state instanceof StructureTerm)
|| 2 != state.arity()
|| !"label".equals(state.name())) {
return invalidResult(submitRule, submitRecord);
}
SubmitRecord.Label lbl = new SubmitRecord.Label();
rec.labels.add(lbl);
lbl.label = checkLabelName(state.arg(0).name());
Term status = state.arg(1);
try {
if ("ok".equals(status.name())) {
lbl.status = SubmitRecord.Label.Status.OK;
appliedBy(lbl, status);
} else if ("reject".equals(status.name())) {
lbl.status = SubmitRecord.Label.Status.REJECT;
appliedBy(lbl, status);
} else if ("need".equals(status.name())) {
lbl.status = SubmitRecord.Label.Status.NEED;
} else if ("may".equals(status.name())) {
lbl.status = SubmitRecord.Label.Status.MAY;
} else if ("impossible".equals(status.name())) {
lbl.status = SubmitRecord.Label.Status.IMPOSSIBLE;
} else {
return invalidResult(submitRule, submitRecord);
}
} catch (UserTermExpected e) {
return invalidResult(submitRule, submitRecord, e.getMessage());
}
}
if (rec.status == SubmitRecord.Status.OK) {
foundOk = true;
break;
}
}
Collections.reverse(out);
// This transformation is required to adapt Prolog's behavior to the way Gerrit handles
// SubmitRecords, as defined in the SubmitRecord#allRecordsOK method.
// When several rules are defined in Prolog, they are all matched to a SubmitRecord. We want
// the change to be submittable when at least one result is OK.
if (foundOk) {
for (SubmitRecord record : out) {
record.status = SubmitRecord.Status.OK;
}
}
return out;
}
@VisibleForTesting
static String checkLabelName(String name) {
try {
return LabelType.checkName(name);
} catch (IllegalArgumentException e) {
String newName = "Invalid-Prolog-Rules-Label-Name-" + sanitizeLabelName(name);
return LabelType.checkName(newName.replace("--", "-"));
}
}
private static String sanitizeLabelName(String name) {
return VALID_LABEL_MATCHER.retainFrom(name);
}
private List invalidResult(Term rule, Term record, String reason) {
return ruleError(
String.format(
"Submit rule %s for change %s of %s output invalid result: %s%s",
rule,
cd.getId(),
cd.project().get(),
record,
(reason == null ? "" : ". Reason: " + reason)));
}
private List invalidResult(Term rule, Term record) {
return invalidResult(rule, record, null);
}
private List ruleError(String err) {
return ruleError(err, null);
}
private List ruleError(String err, Exception e) {
if (opts.logErrors()) {
logger.atSevere().withCause(e).log(err);
return defaultRuleError();
}
return createRuleError(err);
}
/**
* Evaluate the submit type rules to get the submit type.
*
* @return record from the evaluated rules.
*/
public SubmitTypeRecord getSubmitType() {
try {
if (projectState == null) {
throw new NoSuchProjectException(cd.project());
}
} catch (NoSuchProjectException e) {
return typeError("Error looking up change " + cd.getId(), e);
}
List results;
try {
results =
evaluateImpl(
"locate_submit_type",
"get_submit_type",
"locate_submit_type_filter",
"filter_submit_type_results");
} catch (RuleEvalException e) {
return typeError(e.getMessage(), e);
}
if (results.isEmpty()) {
// Should never occur for a well written rule
return typeError(
"Submit rule '"
+ getSubmitRuleName()
+ "' for change "
+ cd.getId()
+ " of "
+ projectState.getName()
+ " has no solution.");
}
Term typeTerm = results.get(0);
if (!(typeTerm instanceof SymbolTerm)) {
return typeError(
"Submit rule '"
+ getSubmitRuleName()
+ "' for change "
+ cd.getId()
+ " of "
+ projectState.getName()
+ " did not return a symbol.");
}
String typeName = typeTerm.name();
try {
return SubmitTypeRecord.OK(SubmitType.valueOf(typeName.toUpperCase()));
} catch (IllegalArgumentException e) {
return typeError(
"Submit type rule "
+ getSubmitRule()
+ " for change "
+ cd.getId()
+ " of "
+ projectState.getName()
+ " output invalid result: "
+ typeName);
}
}
private SubmitTypeRecord typeError(String err) {
return typeError(err, null);
}
private SubmitTypeRecord typeError(String err, Exception e) {
if (opts.logErrors()) {
logger.atSevere().withCause(e).log(err);
return defaultTypeError();
}
return SubmitTypeRecord.error(err);
}
private List evaluateImpl(
String userRuleLocatorName,
String userRuleWrapperName,
String filterRuleLocatorName,
String filterRuleWrapperName)
throws RuleEvalException {
PrologEnvironment env = getPrologEnvironment();
try {
Term sr = env.once("gerrit", userRuleLocatorName, new VariableTerm());
List results = new ArrayList<>();
try {
for (Term[] template : env.all("gerrit", userRuleWrapperName, sr, new VariableTerm())) {
results.add(template[1]);
}
} catch (ReductionLimitException err) {
throw new RuleEvalException(
String.format(
"%s on change %d of %s",
err.getMessage(), cd.getId().get(), projectState.getName()));
} catch (RuntimeException err) {
throw new RuleEvalException(
String.format(
"Exception calling %s on change %d of %s",
sr, cd.getId().get(), projectState.getName()),
err);
}
Term resultsTerm = toListTerm(results);
if (!opts.skipFilters()) {
resultsTerm =
runSubmitFilters(resultsTerm, env, filterRuleLocatorName, filterRuleWrapperName);
}
List r;
if (resultsTerm instanceof ListTerm) {
r = new ArrayList<>();
for (Term t = resultsTerm; t instanceof ListTerm; ) {
ListTerm l = (ListTerm) t;
r.add(l.car().dereference());
t = l.cdr().dereference();
}
} else {
r = Collections.emptyList();
}
submitRule = sr;
return r;
} finally {
env.close();
}
}
private PrologEnvironment getPrologEnvironment() throws RuleEvalException {
PrologEnvironment env;
try {
PrologMachineCopy pmc;
if (opts.rule() == null) {
pmc =
rulesCache.loadMachine(
projectState.getNameKey(), projectState.getConfig().getRulesId());
} else {
pmc = rulesCache.loadMachine("stdin", new StringReader(opts.rule()));
}
env = envFactory.create(pmc);
} catch (CompileException err) {
String msg;
if (opts.rule() == null) {
msg =
String.format(
"Cannot load rules.pl for %s: %s", projectState.getName(), err.getMessage());
} else {
msg = err.getMessage();
}
throw new RuleEvalException(msg, err);
}
env.set(StoredValues.ACCOUNTS, accounts);
env.set(StoredValues.ACCOUNT_CACHE, accountCache);
env.set(StoredValues.EMAILS, emails);
env.set(StoredValues.REVIEW_DB, cd.db());
env.set(StoredValues.CHANGE_DATA, cd);
env.set(StoredValues.PROJECT_STATE, projectState);
return env;
}
private Term runSubmitFilters(
Term results,
PrologEnvironment env,
String filterRuleLocatorName,
String filterRuleWrapperName)
throws RuleEvalException {
PrologEnvironment childEnv = env;
ChangeData cd = env.get(StoredValues.CHANGE_DATA);
ProjectState projectState = env.get(StoredValues.PROJECT_STATE);
for (ProjectState parentState : projectState.parents()) {
PrologEnvironment parentEnv;
try {
parentEnv =
envFactory.create(
rulesCache.loadMachine(
parentState.getNameKey(), parentState.getConfig().getRulesId()));
} catch (CompileException err) {
throw new RuleEvalException("Cannot consult rules.pl for " + parentState.getName(), err);
}
parentEnv.copyStoredValues(childEnv);
Term filterRule = parentEnv.once("gerrit", filterRuleLocatorName, new VariableTerm());
try {
Term[] template =
parentEnv.once(
"gerrit", filterRuleWrapperName, filterRule, results, new VariableTerm());
results = template[2];
} catch (ReductionLimitException err) {
throw new RuleEvalException(
String.format(
"%s on change %d of %s",
err.getMessage(), cd.getId().get(), parentState.getName()));
} catch (RuntimeException err) {
throw new RuleEvalException(
String.format(
"Exception calling %s on change %d of %s",
filterRule, cd.getId().get(), parentState.getName()),
err);
}
childEnv = parentEnv;
}
return results;
}
private void appliedBy(SubmitRecord.Label label, Term status) throws UserTermExpected {
if (status instanceof StructureTerm && status.arity() == 1) {
Term who = status.arg(0);
if (isUser(who)) {
label.appliedBy = new Account.Id(((IntegerTerm) who.arg(0)).intValue());
} else {
throw new UserTermExpected(label);
}
}
}
}