WIP Add API to allow user to enable/disable syslogs on rio

photon-lib/src/main/java/org/photonvision/PhotonSyslog.java

@@ -0,0 +1,148 @@
+package org.photonvision;
+
+import java.io.FileOutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.concurrent.TimeUnit;
+
+public class PhotonSyslog {
+    // Default Settings
+    private String filepath = "/u/logs/photonvision/photonvision.log";
+    private int maxSizeMb = 4;
+    private int logRotations = 5;
+
+    // Implementation defaults (not configurable)
+    private static final Path SYSLOG_CONFIG_PATH = Paths.get("/etc/syslog-ng.d/photonvision.conf");
+    private static final Path LOGROTATE_CONFIG_PATH = Paths.get("/etc/logrotate.d/photonvision.conf");
+    private static final int PV_PORT = 51414;
+
+    public static PhotonSyslog setupSyslog() {
+        return new PhotonSyslog();
+    }
+
+    public static void disable() {
+        try {
+            Files.deleteIfExists(SYSLOG_CONFIG_PATH);
+            Files.deleteIfExists(LOGROTATE_CONFIG_PATH);
+        } catch (Exception e) {}
+    }
+
+    private PhotonSyslog() {}
+
+    public PhotonSyslog setFilePath(String path) {
+        filepath = path;
+        return this;
+    }
+
+    public PhotonSyslog setMaxSizeMb(int megabytes) {
+        maxSizeMb = megabytes;
+        return this;
+    }
+
+    public PhotonSyslog setLogRotations(int rotations) {
+        logRotations = rotations;
+        return this;
+    }
+
+    public void commit() {
+        String SYSLOG_TMP = "/tmp/pvsyslog.conf";
+        String LOGROTATE_TMP = "/tmp/pvlogrotate.conf";
+        try {
+            var syslogFileOutput = new FileOutputStream(SYSLOG_TMP);
+            var logrotateFileOutput = new FileOutputStream(LOGROTATE_TMP);
+
+            syslogFileOutput.write(SyslogConfigFile.generate(filepath, PV_PORT).getBytes());
+            logrotateFileOutput.write(LogRotateConfigFile.generate(filepath, maxSizeMb, logRotations).getBytes());
+
+            syslogFileOutput.close();
+            logrotateFileOutput.close();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+
+        if (moveFile(SYSLOG_TMP, SYSLOG_CONFIG_PATH.toString()) != 0) {
+            System.err.println("Failed to move photonvision syslog config.");
+        }
+
+        if (moveFile(LOGROTATE_TMP, LOGROTATE_CONFIG_PATH.toString()) != 0) {
+            System.err.println("Failed to move photonvision syslog logrotate config.");
+        }
+
+        refreshSyslog();
+    }
+
+    private int execAdmin(String... command) {
+        String[] args = new String[command.length + 2];
+        args[0] = "ssh";
+        args[1] = "admin@localhost";
+        System.arraycopy(command, 0, args, 2, command.length);  
+        return exec(args);
+    }
+
+    private int exec(String... command) {
+        ProcessBuilder pb = new ProcessBuilder(command);
+
+        int exitCode = 0;
+        try {
+            Process process = pb.start();
+
+            process.waitFor(2, TimeUnit.SECONDS);
+            exitCode = process.exitValue();
+        } catch (Exception e) {
+            e.printStackTrace();
+            exitCode = 1;
+        }
+
+        return exitCode;
+    }
+
+    private void refreshSyslog() {
+        // -HUP signal tells syslog to reload config
+        int exitCode = execAdmin("/usr/bin/killall", "-HUP", "syslog-ng");
+
+        if (exitCode != 0) {
+            System.out.println("Failed to restart syslog-ng service with code " + exitCode);
+        }
+    }
+
+    private int moveFile(String src, String dest) {
+        return execAdmin("mv", src, dest);
+    }
+
+    protected static class SyslogConfigFile {
+        private static final String FILE_TEMPLATE = """
+            @version: 3.8
+            
+            source s_photonvision { tcp(ip(0.0.0.0) port(%d) max-connections(100)); udp(); };
+            destination d_photonvision { file("%s"); };
+            
+            log { source(s_photonvision); destination(d_photonvision); };
+            """;
+
+        private static String generate(String filepath, int port) {
+            return String.format(FILE_TEMPLATE, port, filepath);
+        }
+    }
+
+    protected static class LogRotateConfigFile {
+        private static final String FILE_TEMPLATE = """
+            # Logrotate configuration for photonvision logs
+
+            %s {
+                    su lvuser ni
+                    compresscmd /usr/bin/zip
+                    compressext .zip
+                    postrotate
+                            /usr/bin/killall -HUP syslog-ng
+                    endscript
+                    size %dM
+                    rotate %d
+            }
+            """;
+
+        private static String generate(String logpath, int size, int rotate) {
+            return String.format(FILE_TEMPLATE, logpath, size, rotate);
+        }
+    }
+}