Use /etc/os-release if lsb_release is missing (#175)

test/test_unit_query_distro.py

@@ -1,26 +1,30 @@
 """Unit tests: query_distro"""
+import pytest
 
 
-def test_lsb_release_present(runner, yadm, tst_distro):
+@pytest.mark.parametrize(
+    'condition', ['lsb_release', 'os-release', 'missing'])
+def test_query_distro(runner, yadm, tst_distro, tmp_path, condition):
     """Match lsb_release -si when present"""
+    test_release = 'testrelease'
+    lsb_release = ''
+    os_release = tmp_path.joinpath('os-release')
+    if condition == 'os-release':
+        os_release.write_text(f"testing\nID={test_release}\nrelease")
+    if condition != 'lsb_release':
+        lsb_release = 'LSB_RELEASE_PROGRAM="missing_lsb_release"'
     script = f"""
         YADM_TEST=1 source {yadm}
+        {lsb_release}
+        OS_RELEASE="{os_release}"
         query_distro
     """
     run = runner(command=['bash'], inp=script)
     assert run.success
     assert run.err == ''
-    assert run.out.rstrip() == tst_distro
-
-
-def test_lsb_release_missing(runner, yadm):
-    """Empty value when missing"""
-    script = f"""
-        YADM_TEST=1 source {yadm}
-        LSB_RELEASE_PROGRAM="missing_lsb_release"
-        query_distro
-    """
-    run = runner(command=['bash'], inp=script)
-    assert run.success
-    assert run.err == ''
-    assert run.out.rstrip() == ''
+    if condition == 'lsb_release':
+        assert run.out.rstrip() == tst_distro
+    elif condition == 'os-release':
+        assert run.out.rstrip() == test_release
+    else:
+        assert run.out.rstrip() == ''

yadm

@@ -45,6 +45,7 @@ J2CLI_PROGRAM="j2"
 ENVTPL_PROGRAM="envtpl"
 LSB_RELEASE_PROGRAM="lsb_release"
 
+OS_RELEASE="/etc/os-release"
 PROC_VERSION="/proc/version"
 OPERATING_SYSTEM="Unknown"
 
@@ -1219,6 +1220,13 @@ function query_distro() {
   distro=""
   if command -v "$LSB_RELEASE_PROGRAM" >/dev/null 2>&1; then
     distro=$($LSB_RELEASE_PROGRAM -si 2>/dev/null)
+  elif [ -f "$OS_RELEASE" ]; then
+    while IFS='' read -r line || [ -n "$line" ]; do
+      if [[ "$line" = ID=* ]]; then
+        distro="${line#ID=}"
+        break
+      fi
+    done < "$OS_RELEASE"
   fi
   echo "$distro"
 }

yadm.1

@@ -477,7 +477,9 @@ Current user is calculated by running
 .BR distro , " d
 Valid if the value matches the distro.
 Distro is calculated by running
-.BR "lsb_release -si" .
+.B "lsb_release -si"
+or by inspecting the ID from
+.BR "/etc/os-release" .
 .TP
 .BR os , " o
 Valid if the value matches the OS.
@@ -638,6 +640,10 @@ During processing, the following variables are available in the template:
 The OS for "Windows Subsystem for Linux" is reported as "WSL", even
 though uname identifies as "Linux".
 
+.BR NOTE :
+If lsb_release is not available, DISTRO will be the ID specified in
+/etc/os-release.
+
 Examples:
 
 .I whatever##template