[log] allow parts of log messages to be hidden

Fixes #412

NEWS

@@ -12,6 +12,12 @@ lnav v0.8.2:
        command used to rewrite the field in the pretty-printed version of a
        log message.  For example, the HTTP access log format will rewrite the
        status code field to include the textual version (e.g. 200 (OK)).
+     * Log message fields can now be hidden using the 'hide-fields' command or
+       by setting the 'hidden' property in the log format.  When hidden, the
+       fields will be replaced with a yellow ellipsis when displayed.  Hiding
+       large fields that contain extra details can make the log easier to read.
+       The 'x' hotkey can be used to quickly toggle whether these fields are
+       displayed or not.
 
      Interface Changes:
      * The color used for text colored via ":highlight" is now based on the

docs/source/commands.rst

@@ -59,6 +59,13 @@ Display
 * disable-word-wrap - Disable word wrapping in the log and text file views.
 * enable-word-wrap - Enable word wrapping in the log and text file views.
 
+* hide-fields <field-name> [<field-name2> ... <field-nameN>] - Hide large log
+  message fields by replacing them with an ellipsis.  You can quickly switching
+  between showing and hiding hidden fields using the 'x' hotkey.
+
+* show-fields <field-name> [<field-name2> ... <field-nameN>] - Show previously
+  hidden log message fields.
+
 * highlight <regex> - Colorize text that matches the given regex.
 * clear-highlight <regex> - Clear a previous highlight.
 
@@ -147,7 +154,7 @@ The following options are available:
    - open
    - pipe-to
    - pipe-line-to
-   - write-*-to
+   - write-\*-to
 
    This makes it easier to run lnav in restricted environments without the risk
    of privilege escalation.

docs/source/formats.rst

@@ -156,8 +156,12 @@ fields:
       an identifier and should be syntax colored.
     :foreign-key: A boolean that indicates that this field is a key and should
       not be graphed.  This should only need to be set for integer fields.
-    :hidden: A boolean for JSON log fields that indicates whether they should
-      be displayed if they are not present in the line-format.
+    :hidden: A boolean for log fields that indicates whether they should
+      be displayed.  The behavior is slightly different for JSON logs and text
+      logs.  For a JSON log, this property determines whether an extra line
+      will be added with the key/value pair.  For text logs, this property
+      controls whether the value should be displayed by default or replaced
+      with an ellipsis.
     :rewriter: A command to rewrite this field when pretty-printing log
       messages containing this value.  The command must start with ':', ';',
       or '|' to signify whether it is a regular command, SQL query, or a script

docs/source/hotkeys.rst

@@ -216,7 +216,9 @@ Display
        terminal without any decorations so they can be copied easily.
    * - |ks| Ctrl |ke| + |ks| w |ke|
      - Toggle word-wrap.
-
+   * - |ks| x |ke|
+     - Toggle the hiding of log message fields. The hidden fields will be
+       replaced with three bullets and highlighted in yellow.
 
 Session
 -------

src/help.txt

@@ -347,6 +347,10 @@ Display options
 
   CTRL-W            Toggle word-wrapping.
 
+  x                 Toggle the hiding of log message fields.  The hidden fields
+                    will be replaced with three bullets and highlighted in
+                    yellow.
+
   F2                Toggle mouse support.
 
 Query
@@ -481,6 +485,15 @@ COMMANDS
   show-lines-before-and-after
                     Show lines that were hidden by the 'hide-lines' commands.
 
+  hide-fields <field-name> [<field-name2> ... <field-nameN>]
+                    Hide large log message fields by replacing them with an
+                    ellipsis.  You can quickly switching between showing and
+                    hiding hidden fields using the 'x' hotkey.
+
+  show-fields <field-name> [<field-name2> ... <field-nameN>]
+                    Show log messages fields that were previously hidden with
+                    the 'hide-fields' command.
+
   highlight <regex> Highlight strings that match the given regular
                     expression.
 

src/hotkeys.cc

@@ -1213,6 +1213,15 @@ void handle_paging_key(int ch)
             }
             break;
 
+        case 'x':
+            if (tc->toggle_hide_fields()) {
+                lnav_data.ld_rl_view->set_value("Showing hidden fields");
+            } else {
+                lnav_data.ld_rl_view->set_value("Hiding hidden fields");
+            }
+            tc->set_needs_update();
+            break;
+
         case 'X':
             lnav_data.ld_rl_view->set_value(execute_command(ec, "close"));
             break;

src/lnav_commands.cc

@@ -2008,6 +2008,69 @@ static string com_set_min_log_level(exec_context &ec, string cmdline, vector<str
     return retval;
 }
 
+static string com_toggle_field(exec_context &ec, string cmdline, vector<string> &args)
+{
+    string retval;
+
+    if (args.empty()) {
+        args.push_back("colname");
+    } else if (args.size() < 2) {
+        retval = "error: Expecting a log message field name";
+    } else {
+        textview_curses *tc = lnav_data.ld_view_stack.top();
+
+        if (tc != &lnav_data.ld_views[LNV_LOG]) {
+            retval = "error: hiding fields only works in the log view";
+        } else if (tc->get_inner_height() == 0) {
+            retval = "error: no log messages to hide";
+        } else {
+            logfile_sub_source &lss = lnav_data.ld_log_source;
+            content_line_t cl = lss.at(tc->get_top());
+            logfile *lf = lss.find(cl);
+            log_format *format = lf->get_format();
+            bool hide = args[0] == "hide-fields";
+            vector<string> found_fields, missing_fields;
+
+            for (int lpc = 1; lpc < args.size(); lpc++) {
+                const intern_string_t name = intern_string::lookup(args[lpc]);
+
+                if (format->hide_field(name, hide)) {
+                    found_fields.push_back(args[lpc]);
+                    if (hide) {
+                        if (lnav_data.ld_rl_view != NULL) {
+                            lnav_data.ld_rl_view->set_alt_value(
+                                HELP_MSG_1(x, "to quickly show hidden fields"));
+                        }
+                    }
+                    tc->set_needs_update();
+                } else {
+                    missing_fields.push_back(args[lpc]);
+                }
+            }
+
+            if (missing_fields.empty()) {
+                string all_fields = join(found_fields.begin(),
+                                         found_fields.end(),
+                                         ", ");
+
+                if (hide) {
+                    retval = "info: hiding field(s) -- " + all_fields;
+                } else {
+                    retval = "info: showing field(s) -- " + all_fields;
+                }
+            } else {
+                string all_fields = join(missing_fields.begin(),
+                                         missing_fields.end(),
+                                         ", ");
+
+                retval = "error: unknown field(s) -- " + all_fields;
+            }
+        }
+    }
+
+    return retval;
+}
+
 static string com_hide_line(exec_context &ec, string cmdline, vector<string> &args)
 {
     string retval;
@@ -2776,6 +2839,18 @@ readline_context::command_t STD_COMMANDS[] = {
         "Open the help text view",
         com_help,
     },
+    {
+        "hide-fields",
+        "<field-name1> [<field-name2> ... <field-nameN>]",
+        "Hide log message fields by replacing them with an ellipsis",
+        com_toggle_field,
+    },
+    {
+        "show-fields",
+        "<field-name> [<field-name2> ... <field-nameN>]",
+        "Show log message fields that were previously hidden",
+        com_toggle_field,
+    },
     {
         "hide-lines-before",
         "<line#|date>",

src/lnav_util.hh

@@ -46,6 +46,7 @@
 #include <string>
 #include <vector>
 #include <sstream>
+#include <numeric>
 
 #include "ptimec.hh"
 #include "byte_array.hh"
@@ -190,6 +191,22 @@ file_format_t detect_file_format(const std::string &filename);
 
 bool next_format(const char * const fmt[], int &index, int &locked_index);
 
+namespace std {
+    inline string to_string(const string &s) { return s; }
+}
+
+template<class InputIt>
+inline std::string join(InputIt first, InputIt last, const std::string &delim)
+{
+    std::string retval;
+    return std::accumulate(first, last, retval, [&] (
+        typename InputIt::value_type l, typename InputIt::value_type r) {
+        std::string lstr = std::to_string(l);
+
+        return lstr + (lstr.empty() ? "" : delim) + std::to_string(r);
+    });
+}
+
 inline bool is_glob(const char *fn)
 {
     return (strchr(fn, '*') != NULL ||

src/log_data_helper.hh

@@ -115,6 +115,10 @@ public:
             this->ldh_namer.reset(new column_namer());
             this->ldh_json_pairs.clear();
 
+            for (auto lv : this->ldh_line_values) {
+                this->ldh_namer->add_column(lv.lv_name.get());
+            }
+
             for (std::vector<logline_value>::iterator iter =
                  this->ldh_line_values.begin();
                  iter != this->ldh_line_values.end();