Add execute-command-before BuildMutator

- BuildMutator allows commands to be executed prior to the SCENARIO or BUILD phase. Enabled for all types of builds, Gradle, Bazel, Buck, and Maven.

Signed-off-by: Alex Beggs <sunyal@gmail.com>

README.md

@@ -270,6 +270,7 @@ A scenario can define changes that should be applied to the source before each b
 - `clear-project-cache-before`: Deletes the contents of the `.gradle` and `buildSrc/.gradle` project cache directories before the scenario is executed (`SCENARIO`), before cleanup (`CLEANUP`) or before the build is executed (`BUILD`).
 - `clear-transform-cache-before`: Deletes the contents of the transform cache before the scenario is executed (`SCENARIO`), before cleanup (`CLEANUP`) or before the build is executed (`BUILD`).
 - `clear-jars-cache-before`: Deletes the contents of the instrumented jars cache before the scenario is executed (`SCENARIO`), before cleanup (`CLEANUP`) or before the build is executed (`BUILD`).
+- `execute-command-before`: Execute a command before the scenario is executed (SCENARIO) or before the build is executed (BUILD). This can be applied to Gradle, Bazel, Buck, or Maven builds.
 - `git-checkout`: Checks out a specific commit for the build step, and a different one for the cleanup step.
 - `git-revert`: Reverts a given set of commits before the build and resets it afterward.
 - `iterations`: Number of builds to actually measure
@@ -325,11 +326,43 @@ You can compare Gradle against Bazel, Buck, and Maven by specifying their equiva
 
     build_some_target {
         tasks = ["assemble"]
+        execute-command-before = [
+            # Gradle specific executions
+            # Execute a command in the bash shell
+            {
+                schedule = BUILD
+                commands = ["/bin/bash","-c","echo helloworld"]
+            },
+        }
 
         bazel {
             # If empty, it will be infered from BAZEL_HOME environment variable
             home = "/path/to/bazel/home"
             targets = ["build" "//some/target"]
+            execute-command-before = [
+                # Bazel specific executions
+                # execute a command prior to the scenario running.
+                {
+                    schedule = SCENARIO
+                    # Note: Ensure that this is calling the same Bazel that is used in the benchmarks
+                    commands = ["bazel","clean","--expunge"]
+                },
+                # Execute a command in the bash shell
+                {
+                    schedule = BUILD
+                    commands = ["/bin/bash","-c","echo helloworld"]
+                },
+                # Remove the contents of the remote cache Bazel bucket
+                {	
+                    schedule = BUILD
+                    commands = ["gsutil","-o","Credentials:gs_service_key_file=bazel-benchmark-bucket.json","-m","rm","gs://bazel-benchmark-bucket/**"]	
+                },	
+                # Display the total size of the bucket	
+                {	
+                    schedule = BUILD	
+                    commands = ["gsutil","-o","Credentials:gs_service_key_file=bazel-benchmark-bucket.json","du","-sh","gs://bazel-benchmark-bucket"]	
+                },
+            ]
         }
     }
 
@@ -344,6 +377,14 @@ You can compare Gradle against Bazel, Buck, and Maven by specifying their equiva
             # If empty, it will be infered from BUCK_HOME environment variable
             home = "/path/to/buck/home"
             type = "android_binary" // can be a Buck build rule type or "all"
+            execute-command-before = [
+                # Buck specific executions
+                # Execute a command in the bash shell
+                {
+                    schedule = BUILD
+                    commands = ["/bin/bash","-c","echo helloworld"]
+                },
+            }
         }
     }
     build_resources {

src/main/java/org/gradle/profiler/ScenarioUtil.java

@@ -0,0 +1,44 @@
+package org.gradle.profiler;
+
+import static org.gradle.profiler.ScenarioLoader.BAZEL;
+import static org.gradle.profiler.ScenarioLoader.BUCK;
+import static org.gradle.profiler.ScenarioLoader.MAVEN;
+
+import com.typesafe.config.Config;
+import javax.annotation.Nullable;
+
+public class ScenarioUtil {
+
+    /**
+     * Returns the specific config for type of build that is running,
+     * if the scenario doesn't define the build, then this default value is returned
+     *
+     * @param rootScenario the root scenario config
+     * @param settings     the invocation settings that indicates the type of build selected
+     * @param defaultScenario if the scenario doesn't define the build, then this default value is returned, this can be null.
+     * @return if the build config exists or if the scenario doesn't define the build, then this default value is returned
+     */
+    public static Config getBuildConfig(Config rootScenario, InvocationSettings settings, @Nullable
+        Config defaultScenario) {
+        Config scenario;
+        if (settings.isBazel()) {
+            scenario = getConfigOrDefault(rootScenario, BAZEL, defaultScenario);
+        } else if (settings.isBuck()) {
+            scenario = getConfigOrDefault(rootScenario, BUCK, defaultScenario);
+        } else if (settings.isMaven()) {
+            scenario = getConfigOrDefault(rootScenario, MAVEN, defaultScenario);
+        } else {
+            scenario = rootScenario;
+        }
+        return scenario;
+    }
+
+    private static Config getConfigOrDefault(Config rootScenario, String key, @Nullable Config defaultScenario) {
+        Config scenario;
+        if (rootScenario.hasPath(key)) {
+            scenario = rootScenario.getConfig(key);
+        } else {
+            scenario = defaultScenario;
+        } return scenario;
+    }
+}

src/main/java/org/gradle/profiler/mutations/BuildMutatorConfigurator.java

@@ -5,5 +5,17 @@
 import org.gradle.profiler.InvocationSettings;
 
 public interface BuildMutatorConfigurator {
+
+    /**
+     * This should only be called when {@see #enabled} returns true
+     */
 	BuildMutator configure(Config scenario, String scenarioName, InvocationSettings settings, String key);
+
+    /**
+     * Returns true if this BuildMutator is enabled for targeted scenario. This can filter
+     * on specific build types.
+     */
+	default boolean enabled(Config scenario, String scenarioName, InvocationSettings settings, String key) {
+	    return scenario.hasPath(key);
+    }
 }

src/main/java/org/gradle/profiler/mutations/CommandInvoker.java

@@ -0,0 +1,16 @@
+package org.gradle.profiler.mutations;
+
+import java.util.List;
+
+/**
+ * Interface which provides a means to execute a command
+ */
+public interface CommandInvoker {
+
+    /**
+     * @param command the command to execute
+     * @return the exit code of the result of executing the command
+     */
+    int execute(List<String> command);
+
+}

src/main/java/org/gradle/profiler/mutations/ExecuteCommandBuildMutator.java

@@ -0,0 +1,117 @@
+package org.gradle.profiler.mutations;
+
+import static org.gradle.profiler.ScenarioUtil.getBuildConfig;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.typesafe.config.Config;
+import java.util.ArrayList;
+import java.util.List;
+import org.gradle.profiler.BuildContext;
+import org.gradle.profiler.BuildMutator;
+import org.gradle.profiler.CompositeBuildMutator;
+import org.gradle.profiler.ConfigUtil;
+import org.gradle.profiler.InvocationSettings;
+import org.gradle.profiler.ScenarioContext;
+
+public class ExecuteCommandBuildMutator implements BuildMutator {
+
+    private ExecuteCommandSchedule schedule;
+    private List<String> commands;
+    private CommandInvoker commandInvoker;
+
+    public ExecuteCommandBuildMutator(ExecuteCommandSchedule schedule,
+        List<String> commands, CommandInvoker commandInvoker) {
+        this.schedule = schedule;
+        this.commands = commands;
+        this.commandInvoker = commandInvoker;
+    }
+
+    @Override
+    public void beforeBuild(BuildContext context) {
+        if (schedule == ExecuteCommandSchedule.BUILD) {
+            execute();
+        }
+    }
+
+    @Override
+    public void beforeScenario(ScenarioContext context) {
+        if (schedule == ExecuteCommandSchedule.SCENARIO) {
+            execute();
+        }
+    }
+
+    protected void execute() {
+        String commandStr = String.join(" ", commands);
+        System.out.println(String.format("> Executing command `%s`", commandStr));
+        int result = commandInvoker.execute(commands);
+        if (result != 0) {
+            System.err.println(
+                String.format("Unexpected exit code %s for command `%s`", result, commandStr)
+            );
+        }
+    }
+
+    public static class Configurator implements BuildMutatorConfigurator {
+
+        private CommandInvoker commandInvoker;
+
+        public Configurator() {
+            this(new ProcessBuilderCommandInvoker());
+        }
+
+        @VisibleForTesting
+        Configurator(CommandInvoker commandInvoker) {
+            this.commandInvoker = commandInvoker;
+        }
+
+        private BuildMutator newInstance(Config scenario, String scenarioName,
+            InvocationSettings settings, String key,
+            CommandInvoker commandInvoker, ExecuteCommandSchedule schedule, List<String> commands) {
+            return new ExecuteCommandBuildMutator(schedule, commands, commandInvoker);
+        }
+
+        @Override
+        public BuildMutator configure(Config rootScenario, String scenarioName,
+            InvocationSettings settings, String key) {
+            Config scenario = getBuildConfig(rootScenario, settings, null);
+            final List<BuildMutator> mutators = new ArrayList<>();
+            final List<? extends Config> list = scenario.getConfigList(key);
+            for (Config config : list) {
+                final ExecuteCommandSchedule schedule = ConfigUtil
+                    .enumValue(config, "schedule", ExecuteCommandSchedule.class, null);
+                if (schedule == null) {
+                    throw new IllegalArgumentException(
+                        "Schedule for executing commands is not specified");
+                }
+                List<String> commands = ConfigUtil.strings(config, "commands");
+                if (commands.isEmpty()) {
+                    throw new IllegalArgumentException(
+                        String.format(
+                            "No commands specified for 'execute-command-before' in scenario %s",
+                            scenarioName)
+                    );
+                }
+                mutators.add(
+                    newInstance(scenario, scenarioName, settings, key, commandInvoker, schedule,
+                        commands));
+            }
+            return new CompositeBuildMutator(mutators);
+        }
+
+        public boolean enabled(Config rootScenario, String scenarioName, InvocationSettings settings, String key) {
+            Config scenario = getBuildConfig(rootScenario, settings, null);
+            return scenario != null && scenario.hasPath(key) && !scenario.getConfigList(key)
+                .isEmpty();
+        }
+    }
+
+    @Override
+    public String toString() {
+        return getClass().getSimpleName() + "(" + schedule + ")";
+    }
+
+    public enum ExecuteCommandSchedule {
+        SCENARIO, BUILD
+    }
+
+}

src/main/java/org/gradle/profiler/mutations/ProcessBuilderCommandInvoker.java

@@ -0,0 +1,24 @@
+package org.gradle.profiler.mutations;
+
+import java.io.IOException;
+import java.util.List;
+
+public class ProcessBuilderCommandInvoker implements CommandInvoker {
+
+    @Override
+    public int execute(List<String> command) {
+        try {
+            if (command == null || command.isEmpty()) {
+                throw new IllegalArgumentException(
+                    String.format("command cannot be null or empty, was %s", command));
+            }
+            ProcessBuilder processBuilder = new ProcessBuilder(command)
+                .redirectOutput(ProcessBuilder.Redirect.INHERIT)
+                .redirectError(ProcessBuilder.Redirect.INHERIT);
+            Process process = processBuilder.start();
+            return process.waitFor();
+        } catch (IOException | InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}