[#628] Add compression connector

classes/local/step/compression_trait.php

@@ -0,0 +1,265 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace tool_dataflows\local\step;
+
+use coding_exception;
+use tool_dataflows\helper;
+
+/**
+ * File compression trait
+ *
+ * @package    tool_dataflows
+ * @author     Matthew Hilton <matthewhilton@catalyst-au.net>
+ * @copyright  Catalyst IT, 2022
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+trait compression_trait {
+    /**
+     * Returns whether or not the step configured, has a side effect.
+     *
+     * @return bool whether or not this step has a side effect
+     */
+    public function has_side_effect(): bool {
+        if (isset($this->stepdef)) {
+            $config = $this->get_variables()->get('config');
+            return !helper::path_is_relative($config->to);
+        }
+        return true;
+    }
+
+    /**
+     * Return the definition of the fields available in this form.
+     *
+     * @return array
+     */
+    public static function form_define_fields(): array {
+        return [
+            'command' => ['type' => PARAM_TEXT, 'required' => true],
+            'method' => ['type' => PARAM_TEXT, 'required' => true],
+            'from'   => ['type' => PARAM_TEXT, 'required' => true],
+            'to'     => ['type' => PARAM_TEXT, 'required' => true],
+        ];
+    }
+
+    /**
+     * Custom elements for editing the connector.
+     *
+     * @param \MoodleQuickForm $mform
+     */
+    public function form_add_custom_inputs(\MoodleQuickForm &$mform) {
+
+        $mform->addElement('select', 'config_command', get_string('compression:command', 'tool_dataflows'), [
+            'compress' => get_string('compression:compress', 'tool_dataflows'),
+            'decompress' => get_string('compression:decompress', 'tool_dataflows'),
+        ]);
+
+        // Build the selector options using the supported methods as the source.
+        $supportedmethods = $this->get_supported_methods();
+        $methodkeys = array_keys($supportedmethods);
+        $methodvalues = array_column($supportedmethods, 'name');
+        $methodoptions = array_combine($methodkeys, $methodvalues);
+
+        $mform->addElement('select', 'config_method', get_string('compression:method', 'tool_dataflows'), $methodoptions);
+
+        // From / Source path.
+        $mform->addElement('text', 'config_from', get_string('compression:from', 'tool_dataflows'));
+        $mform->addRule('config_from', get_string('required'), 'required', null, 'client');
+
+        // To / Target path.
+        $mform->addElement('text', 'config_to', get_string('compression:to', 'tool_dataflows'));
+        $mform->addRule('config_to', get_string('required'), 'required', null, 'client');
+    }
+
+    /**
+     * Executes the step
+     *
+     * @param  mixed|null $input
+     * @return mixed
+     */
+    public function execute($input = null) {
+        $variables = $this->get_variables();
+        $config = $variables->get('config');
+        $config->from = $this->enginestep->engine->resolve_path($config->from);
+        $config->to = $this->enginestep->engine->resolve_path($config->to);
+
+        // Check that the from path exists.
+        if (!is_file($config->from)) {
+            $this->enginestep->log($config->from . ' file does not exist');
+            $variables->set('vars.success', false);
+            return $input;
+        }
+
+        // We do not need to go any further if it is a dry run.
+        if ($this->is_dry_run() && $this->has_side_effect()) {
+            return $input;
+        }
+
+        $result = $this->execute_method($config);
+
+        if ($result !== true) {
+            // Log the error.
+            $this->enginestep->log($result);
+        }
+
+        $variables->set('vars.success', $result === true);
+
+        return $input;
+    }
+
+    /**
+     * Perform any extra validation that is required only for runs.
+     *
+     * @return true|array Will return true or an array of errors.
+     */
+    public function validate_for_run() {
+        $config = $this->get_variables()->get('config');
+
+        $errors = [];
+
+        $error = helper::path_validate($config->from);
+        if ($error !== true) {
+            $errors['config_from'] = $error;
+        }
+
+        $error = helper::path_validate($config->to);
+        if ($error !== true) {
+            $errors['config_to'] = $error;
+        }
+
+        // Valid the chosen methods executable is actually executable.
+        $method = $this->get_method($config->method);
+        $error = ($method->isexecutable)();
+        if ($error !== true) {
+            $errors['config_method'] = $error;
+        }
+
+        return $errors ?: true;
+    }
+
+    /**
+     * A list of outputs and their description if applicable.
+     *
+     * @return  array of outputs
+     */
+    public function define_outputs(): array {
+        return ['success' => get_string('compression:output_success', 'tool_dataflows')];
+    }
+
+    /**
+     * Returns the method info that has been selected in the configuration.
+     * @param string $method method name
+     * @return object method information (name, path, etc...)
+     */
+    private function get_method(string $method): object {
+        $methods = $this->get_supported_methods();
+
+        // If not defined it means something has gone very wrong.
+        // this should almost always be defined.
+        if (!isset($methods[$method])) {
+            throw new coding_exception($method . ' is not defined as a supported method.');
+        }
+
+        return $methods[$method];
+    }
+
+    /**
+     * Returns an array of supported methods by this step and information about them.
+     * @return array array of objects containing the information about each method
+     */
+    private function get_supported_methods(): array {
+        return [
+            'gzip' => (object) [
+                'name' => get_string('compression:method:gzip', 'tool_dataflows'),
+                'isexecutable' => function() {
+                    return self::validate_executable(get_config('tool_dataflows', 'gzip_exec_path'));
+                }
+            ]
+        ];
+    }
+
+    /**
+     * Validates the executable
+     * @param string $path path to executable.
+     * @return string|true string if error, else true if valid.
+     */
+    private static function validate_executable(string $path) {
+        if (!is_executable($path)) {
+            return get_string('compression:error:invalidexecutable', 'tool_dataflows', [
+                'path' => $path
+            ]);
+        }
+
+        return true;
+    }
+
+    /**
+     * Executes the configured method.
+     *
+     * @param object $config step configuration
+     * @return string|true string if error, else true if success
+     */
+    private function execute_method($config) {
+        switch ($config->method) {
+            case 'gzip':
+                return $this->execute_gzip($config);
+            default:
+                throw new coding_exception($config->method . ' has no executable setup.');
+        }
+    }
+
+    /**
+     * Executes the gzip method.
+     *
+     * @param object $config
+     * @return string|error string if error, else true if success.
+     */
+    private function execute_gzip($config) {
+        $gzip = get_config('tool_dataflows', 'gzip_exec_path');
+        $from = escapeshellarg($config->from);
+        $to = escapeshellarg($config->to);
+
+        $compressionmode = $config->command == 'decompress' ? '-d' : '';
+        $movefilename = $config->command == 'compress' ? $config->from . '.gz' : rtrim($config->from, '.gz');
+        $movefilename = escapeshellarg($movefilename);
+
+        // See https://www.gnu.org/software/gzip/manual/html_node/Invoking-gzip.html.
+        // -f: force override destination file if it exists
+        // -v: verbose
+        // -k: keep input file
+        // 2>&1: pipe stderror to stdout.
+        $gzipcommand = "{$gzip} -f -v -k {$compressionmode} {$from} 2>&1 && mv {$movefilename} {$to}";
+        $this->enginestep->log("Command: " . $gzipcommand);
+
+        // Execute the gzip command.
+        $output = [];
+        $result = null;
+        exec($gzipcommand, $output, $result);
+        $success = $result === 0;
+        $this->enginestep->log(
+            $success
+                ? 'Success'
+                : 'Fail' . PHP_EOL . implode(PHP_EOL, $output)
+        );
+
+        // Emit in error logs.
+        if (!$success) {
+            return implode(PHP_EOL, $output);
+        }
+
+        return true;
+    }
+}

classes/local/step/connector_compression.php

@@ -0,0 +1,35 @@
+<?php
+// This file is part of Moodle - https://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace tool_dataflows\local\step;
+
+/**
+ * Connector step for GPG encryption/decryption
+ *
+ * @package    tool_dataflows
+ * @author     Matthew Hilton <matthewhilton@catalyst-au.net>
+ * @copyright  2023, Catalyst IT
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class connector_compression extends connector_step {
+    use compression_trait;
+
+    /** @var int[] number of output flows (min, max). */
+    protected $outputflows = [0, 1];
+
+    /** @var int[] number of output connectors (min, max). */
+    protected $outputconnectors = [0, 1];
+}

lang/en/tool_dataflows.php

@@ -41,6 +41,8 @@
       def: 12  # Accessed as \${{global.vars.abc.def}}";
 $string['gpg_exec_path'] = 'Path to GPG executable';
 $string['gpg_exec_path_desc'] = 'Path to GPG executable';
+$string['gzip_exec_path'] = 'Path to gzip executable';
+$string['gzip_exec_path_desc'] = 'Path to gzip executable';
 $string['gpg_key_dir'] = 'Path to keyring directory';
 $string['gpg_key_dir_desc'] = 'Path to keyring directory';
 $string['log_handlers'] = 'Log handlers';
@@ -129,6 +131,7 @@
 $string['step_name_connector_sftp_directory_file_list'] = 'SFTP directory file list';
 $string['step_name_connector_abort'] = 'Abort connector';
 $string['step_name_connector_append_file'] = 'Append file';
+$string['step_name_connector_compression'] = 'Compression/Decompression';
 $string['step_name_connector_copy_file'] = 'Copy File';
 $string['step_name_connector_curl'] = 'Curl connector';
 $string['step_name_connector_debug_file_display'] = 'File contents display';
@@ -599,3 +602,14 @@
 
 // Remove file step.
 $string['remove_file:file'] = 'File path to be removed';
+
+// Compression step.
+$string['compression:compress'] = 'Compress';
+$string['compression:decompress'] = 'Decompress';
+$string['compression:command'] = 'Command';
+$string['compression:method'] = 'Method';
+$string['compression:method:gzip'] = 'gzip';
+$string['compression:from'] = 'Source';
+$string['compression:to'] = 'Destination';
+$string['compression:output_success'] = 'Success';
+$string['compression:error:invalidexecutable'] = '{$a->path} is not executable';

lib.php

@@ -51,6 +51,7 @@ function tool_dataflows_step_types() {
         new step\connector_abort,
         new step\connector_append_file,
         new step\connector_curl,
+        new step\connector_compression,
         new step\connector_copy_file,
         new step\connector_debug_file_display,
         new step\connector_debugging,

settings.php

@@ -128,6 +128,15 @@
             )
         );
 
+        $settings->add(
+            new admin_setting_configexecutable(
+                'tool_dataflows/gzip_exec_path',
+                get_string('gzip_exec_path', 'tool_dataflows'),
+                get_string('gzip_exec_path_desc', 'tool_dataflows'),
+                '/usr/bin/gzip'
+            )
+        );
+
         $settings->add(
             new admin_setting_configtext(
                 'tool_dataflows/gpg_key_dir',