curl.ipp

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#include <adc/builder/builder.hpp>
#include <adc/publisher/publisher.hpp>
#include <cstdlib>
#include <iostream>
#include <fstream>
#include <filesystem>
#include <unistd.h>
 
namespace adc {
 
using std::cout;
 
typedef std::string string;
typedef std::string_view string_view;
 
/*! \brief Curl utility publisher_api implementation.
  This plugin generates a scratch file (in-memory) and asynchronously
  sends it to the configured web service by invoking the 'curl' utility.
  Multiple independent instances of this plugin may be used simultaneously.
 */
class curl_plugin : public publisher_api {
    enum state {
        ok,
        err
    };
    enum mode {
        /* the next mode needed for correct operation */
        pi_config,
        pi_init,
        pi_pub_or_final
    };
    
public:
    /// \brief default scratch directory for curl utility messages.
    /// This directory must be globally writable and should be fast.
    /// Overridden with env("ADC_CURL_PLUGIN_DIRECTORY").
    inline static const char *adc_curl_plugin_directory_default = "/dev/shm/adc";
 
    /// \brief default full path to curl utility
    /// This program should be world accessible.
    /// Overridden with env("ADC_CURL_PLUGIN_PROG").
    inline static const char *adc_curl_plugin_prog_default = "/usr/bin/curl";
 
    /// \brief default ADC server https port.
    /// The server should be highly available.
    /// Overridden with env("ADC_CURL_PLUGIN_PORT").
    inline static const char *adc_curl_plugin_port_default = "443";
 
    /// \brief ADC data ingest server host.
    /// The server should be highly available; the
    /// default value of https://localhost must be overridden by an
    /// environment variable unless the test environment includes a test server.
    /// Overridden with env("ADC_CURL_PLUGIN_URL").
    inline static const char *adc_curl_plugin_url_default = "https://localhost";
 
    /// \brief ADC curl plugin enable debug messages; (default "0": none)
    /// "2" provides message send debugging
    /// "1" provides lighter debugging
    /// Overridden with env("ADC_CURL_PLUGIN_DEBUG").
    inline static const char *adc_curl_plugin_debug_default = "0";
 
private:
    inline static const char *plugin_prefix = "ADC_CURL_PLUGIN_";
    inline static const std::map< const string, const string > plugin_config_defaults =
    {       {"DIRECTORY", adc_curl_plugin_directory_default},
        {"PROG", adc_curl_plugin_prog_default},
        {"URL", adc_curl_plugin_url_default},
        {"PORT", adc_curl_plugin_port_default},
        {"DEBUG", adc_curl_plugin_debug_default}
    };
 
    const string vers;
    const std::vector<string> tags;
    string fdir;
    string prog;
    string port;
    string url;
    int debug;
    enum state state;
    bool paused;
    enum mode mode;
 
    int config(const string& dir, string_view surl, string_view sport, string_view sprog, const string& sdebug) {
        if (mode != pi_config)
            return 2;
 
        uid_t ui = geteuid();
        fdir = dir + string("/") + std::to_string(ui);
        port = sport;
        url = surl;
        prog = sprog;
        mode = pi_init;
        std::stringstream ss(sdebug);
        ss >> debug;
        if (debug < 0) {
            debug = 0;
        }
        if (debug > 0) {
            std::cout<< "curl plugin configured" <<std::endl;
        }
        return 0;
    }
 
    // find field in m, then with prefix in env, then the default.
    const string get(const std::map< string, string >& m,
            string field, string_view env_prefix) {
        // fields not defined in config_defaults raise an exception.
        auto it = m.find(field);
        if (it != m.end()) {
            return it->second;
        }
        string en = string(env_prefix) += field;
        char *ec = getenv(en.c_str());
        if (!ec) {
            return plugin_config_defaults.at(field);
        } else {
            return string(ec);
        }
    }
    
    string get_temp_file_name() {
        string tplt = fdir + "/json-curl-msg-XXXXXX";
        char * cstr = new char [tplt.length()+1];
        std::strcpy (cstr, tplt.c_str());
        int fd = mkstemp(cstr);
        if (fd >= 0) {
            string f(cstr);
            delete[] cstr;
            close(fd);
            // current user now owns tempfile.
            return f;
        }
        std::cout<< "mkstemp failed" <<std::endl;
        delete[] cstr;
        return "";
    }
 
    // invoke curl with json in f, then delete f.
    // wrap this in a thread to make it non-blocking eventually.
    int curl_send(string& f)
    {
        if (debug == 2) {
            // do not suppress stderr/stdout from system call
            string cmd = "(" + prog + 
                " -X POST -s -w \"\n%{http_code}\n\" -H \"Content-Type: application/json\" -d @"
                + f + " " + url + " || /bin/rm -f " + f + ") &";
            int err1 = std::system(cmd.c_str());
            std::cout << "cmd:" << cmd << std::endl;
            std::cout << err1 << std::endl;
            std::cout << f << std::endl;
        } else {
            // suppress stderr/stdout from system call
            string qcmd = "(" + prog + 
                " -X POST -s -w \"\n%{http_code}\n\" -H \"Content-Type: application/json\" -d @"
                + f + " " + url + 
                " > /dev/null 2>&1 ; /bin/rm -f " + f + ") &";
            int err2 = std::system(qcmd.c_str());
            if (debug) {
                std::cout << err2 << std::endl;
            }
        }
        return 0;
    }
 
public:
    curl_plugin() : vers("1.0.0") , state(ok), paused(false), mode(pi_config) { }
 
    /*!
     */
        int publish(std::shared_ptr<builder_api> b) {
        if (paused)
            return 0;
        if (state != ok)
            return 1;
        if (mode != pi_pub_or_final)
            return 2;
        // write to tmpfile, curl, and then delete
        // this could be made fancy with a work queue in a later reimplementation.
        // try for /dev/shm/adc for performance and fall back to tmpdir
        string fname = get_temp_file_name();
        if (debug) {
            std::cout << "name: " << fname <<std::endl;
        }
        // open dump file
        std::ofstream out(fname);
        if (out.good()) {
            out << b->serialize() << std::endl;
            if (out.good()) {
                if (debug) {
                    std::cout << "'curl' wrote" << std::endl;
                }
                out.close();
                curl_send(fname); // send also removes file
                return 0;
            } else {
                std::cout << "failed write" << std::endl;
                return 1;
            }
        }
        std::filesystem::remove(fname);
        std::cout << "failed open " << fname << std::endl;
        return 1;
    }
 
    /*!
     */
        int config(const std::map< std::string, std::string >& m) {
        return config(m, plugin_prefix);
    }
 
    /*!
     */
        int config(const std::map< std::string, std::string >& m, string_view env_prefix) {
        string d = get(m, "DIRECTORY", env_prefix);
        string url = get(m, "URL", env_prefix);
        string port = get(m, "PORT", env_prefix);
        string prog = get(m, "PROG", env_prefix);
        string sdebug = get(m, "DEBUG", env_prefix);
        return config(d, url, port, prog, sdebug);
    }
        
    const std::map< const std::string, const std::string> & get_option_defaults() {
        return plugin_config_defaults;
    }
 
    int initialize() {
        std::map <string, string >m;
        // config if never config'd
        if (!fdir.size())
            config(m);
        if (mode != pi_init) {
            return 2;
        }
        if ( state == err ) {
            std::cout << "curl plugin initialize found pre-existing error" << std::endl;
            return 3;
        }
        std::error_code ec;
        std::filesystem::create_directories(fdir, ec);
        if (ec.value() != 0 && ec.value() != EEXIST ) {
            state = err;
            std::cout << "unable to create scratch directory for plugin 'curl'; "
                    << fdir << " : " << ec.message() << std::endl;
            return ec.value();
        } else {
            if (debug) {
                std::cout << "created " << fdir <<std::endl;
            }
            mode = pi_pub_or_final;
        }
        return 0;
    }
 
        void finalize() {
        if (mode == pi_pub_or_final) {
            state = ok;
            paused = false;
            mode = pi_config;
        } else {
            if (debug) {
                std::cout << "curl plugin finalize on non-running plugin" << std::endl;
            }
        }
    }
 
    void pause() {
        paused = true;
    }
 
        void resume() {
        paused = false;
    }
 
    string_view name() const {
        return "curl";
    }
 
    string_view version() const {
        return vers;
    }
 
    ~curl_plugin() {
        if (debug) {
            std::cout << "Destructing curl_plugin" << std::endl;
        }
    }
};
 
} // adc