Add setting in config to control truncating field values. (#1285)

* Add setting in config to truncate field value.

* Black.

* Changelog.

* Fix tests.

7 files changed, 86 insertions, 33 deletions

diff --git a/changelog.rst b/changelog.rst
index d7320883..3cfeb865 100644
--- a/changelog.rst
+++ b/changelog.rst
@@ -4,10 +4,12 @@ TBD
 Features:
 ---------
 
+* Add `max_field_width` setting to config, to enable more control over field truncation ([related issue](https://github.com/dbcli/pgcli/issues/1250)).
+
 Bug fixes:
 ----------
 
-3.2.0 
+3.2.0
 =====
 
 Release date: 2021/08/23
diff --git a/pgcli/main.py b/pgcli/main.py
index 5135f6fd..124cac5c 100644
--- a/pgcli/main.py
+++ b/pgcli/main.py
@@ -86,6 +86,7 @@ from textwrap import dedent
 
 # Ref: https://stackoverflow.com/questions/30425105/filter-special-chars-such-as-color-codes-from-shell-output
 COLOR_CODE_REGEX = re.compile(r"\x1b(\[.*?[@-~]|\].*?(\x07|\x1b\\))")
+DEFAULT_MAX_FIELD_WIDTH = 500
 
 # Query tuples are used for maintaining history
 MetaQuery = namedtuple(
@@ -106,7 +107,7 @@ MetaQuery.__new__.__defaults__ = ("", False, 0, 0, False, False, False, False)
 
 OutputSettings = namedtuple(
     "OutputSettings",
-    "table_format dcmlfmt floatfmt missingval expanded max_width case_function style_output",
+    "table_format dcmlfmt floatfmt missingval expanded max_width case_function style_output max_field_width",
 )
 OutputSettings.__new__.__defaults__ = (
     None,
@@ -117,6 +118,7 @@ OutputSettings.__new__.__defaults__ = (
     None,
     lambda x: x,
     None,
+    DEFAULT_MAX_FIELD_WIDTH,
 )
 
 
@@ -201,6 +203,16 @@ class PGCli:
         else:
             self.row_limit = c["main"].as_int("row_limit")
 
+        # if not specified, set to DEFAULT_MAX_FIELD_WIDTH
+        # if specified but empty, set to None to disable truncation
+        # ellipsis will take at least 3 symbols, so this can't be less than 3 if specified and > 0
+        max_field_width = c["main"].get("max_field_width", DEFAULT_MAX_FIELD_WIDTH)
+        if max_field_width and max_field_width.lower() != "none":
+            max_field_width = max(3, abs(int(max_field_width)))
+        else:
+            max_field_width = None
+        self.max_field_width = max_field_width
+
         self.min_num_menu_lines = c["main"].as_int("min_num_menu_lines")
         self.multiline_continuation_char = c["main"]["multiline_continuation_char"]
         self.table_format = c["main"]["table_format"]
@@ -934,6 +946,7 @@ class PGCli:
                     else lambda x: x
                 ),
                 style_output=self.style_output,
+                max_field_width=self.max_field_width,
             )
             execution = time() - start
             formatted = format_output(title, cur, headers, status, settings)
@@ -1444,6 +1457,7 @@ def format_output(title, cur, headers, status, settings):
         "disable_numparse": True,
         "preserve_whitespace": True,
         "style": settings.style_output,
+        "max_field_width": settings.max_field_width,
     }
     if not settings.floatfmt:
         output_kwargs["preprocessors"] = (align_decimals,)
diff --git a/pgcli/pgclirc b/pgcli/pgclirc
index 15c10f5e..6654ce92 100644
--- a/pgcli/pgclirc
+++ b/pgcli/pgclirc
@@ -119,6 +119,12 @@ on_error = STOP
 # Set threshold for row limit. Use 0 to disable limiting.
 row_limit = 1000
 
+# Truncate long text fields to this value for tabular display (does not apply to csv).
+# Leave unset to disable truncation. Example: "max_field_width = "
+# Be aware that formatting might get slow with values larger than 500 and tables with
+# lots of records.
+max_field_width = 500
+
 # Skip intro on startup and goodbye on exit
 less_chatty = False
 
diff --git a/tests/features/steps/auto_vertical.py b/tests/features/steps/auto_vertical.py
index 1643ea5e..d7cdccd4 100644
--- a/tests/features/steps/auto_vertical.py
+++ b/tests/features/steps/auto_vertical.py
@@ -24,11 +24,11 @@ def step_see_small_results(context):
         context,
         dedent(
             """\
-        +------------+\r
-        | ?column?   |\r
-        |------------|\r
-        | 1          |\r
-        +------------+\r
+        +----------+\r
+        | ?column? |\r
+        |----------|\r
+        | 1        |\r
+        +----------+\r
         SELECT 1\r
         """
         ),
diff --git a/tests/features/steps/basic_commands.py b/tests/features/steps/basic_commands.py
index 07e9ec17..7ca20f06 100644
--- a/tests/features/steps/basic_commands.py
+++ b/tests/features/steps/basic_commands.py
@@ -118,11 +118,11 @@ def step_see_found(context):
         + "\r"
         + dedent(
             """
-            +------------+\r
-            | ?column?   |\r
-            |------------|\r
-            | found      |\r
-            +------------+\r
+            +----------+\r
+            | ?column? |\r
+            |----------|\r
+            | found    |\r
+            +----------+\r
             SELECT 1\r
         """
         )
diff --git a/tests/features/steps/expanded.py b/tests/features/steps/expanded.py
index 265ea39b..ac84c41c 100644
--- a/tests/features/steps/expanded.py
+++ b/tests/features/steps/expanded.py
@@ -58,11 +58,11 @@ def step_see_data(context, which):
             context,
             dedent(
                 """\
-                +-----+-----+--------+\r
-                | x   | y   | z      |\r
-                |-----+-----+--------|\r
-                | 1   | 1.0 | 1.0000 |\r
-                +-----+-----+--------+\r
+                +---+-----+--------+\r
+                | x | y   | z      |\r
+                |---+-----+--------|\r
+                | 1 | 1.0 | 1.0000 |\r
+                +---+-----+--------+\r
                 SELECT 1\r
             """
             ),
diff --git a/tests/test_main.py b/tests/test_main.py
index c48accbe..2526062f 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -61,16 +61,47 @@ def test_format_output():
     )
     expected = [
         "Title",
-        "+---------+---------+",
-        "| head1   | head2   |",
-        "|---------+---------|",
-        "| abc     | def     |",
-        "+---------+---------+",
+        "+-------+-------+",
+        "| head1 | head2 |",
+        "|-------+-------|",
+        "| abc   | def   |",
+        "+-------+-------+",
         "test status",
     ]
     assert list(results) == expected
 
 
+def test_format_output_truncate_on():
+    settings = OutputSettings(
+        table_format="psql", dcmlfmt="d", floatfmt="g", max_field_width=10
+    )
+    results = format_output(
+        None,
+        [("first field value", "second field value")],
+        ["head1", "head2"],
+        None,
+        settings,
+    )
+    expected = [
+        "+------------+------------+",
+        "| head1      | head2      |",
+        "|------------+------------|",
+        "| first f... | second ... |",
+        "+------------+------------+",
+    ]
+    assert list(results) == expected
+
+
+def test_format_output_truncate_off():
+    settings = OutputSettings(
+        table_format="psql", dcmlfmt="d", floatfmt="g", max_field_width=None
+    )
+    long_field_value = ("first field " * 100).strip()
+    results = format_output(None, [(long_field_value,)], ["head1"], None, settings)
+    lines = list(results)
+    assert lines[3] == f"| {long_field_value} |"
+
+
 @dbtest
 def test_format_array_output(executor):
     statement = """
@@ -83,12 +114,12 @@ def test_format_array_output(executor):
     """
     results = run(executor, statement)
     expected = [
-        "+----------------+------------------------+--------------+",
-        "| bigint_array   | nested_numeric_array   | 配列         |",
-        "|----------------+------------------------+--------------|",
-        "| {1,2,3}        | {{1,2},{3,4}}          | {å,魚,текст} |",
-        "| {}             | <null>                 | {<null>}     |",
-        "+----------------+------------------------+--------------+",
+        "+--------------+----------------------+--------------+",
+        "| bigint_array | nested_numeric_array | 配列         |",
+        "|--------------+----------------------+--------------|",
+        "| {1,2,3}      | {{1,2},{3,4}}        | {å,魚,текст} |",
+        "| {}           | <null>               | {<null>}     |",
+        "+--------------+----------------------+--------------+",
         "SELECT 2",
     ]
     assert list(results) == expected
@@ -128,11 +159,11 @@ def test_format_output_auto_expand():
     )
     table = [
         "Title",
-        "+---------+---------+",
-        "| head1   | head2   |",
-        "|---------+---------|",
-        "| abc     | def     |",
-        "+---------+---------+",
+        "+-------+-------+",
+        "| head1 | head2 |",
+        "|-------+-------|",
+        "| abc   | def   |",
+        "+-------+-------+",
         "test status",
     ]
     assert list(table_results) == table