DOC: add shell command ex. to capture_logs example

examples/capture_logs.py

@@ -2,13 +2,32 @@
 
 import random
 import sys
+import subprocess
 
 import psweep as ps
 
 
+def call(cmd: str):
+    """Execute shell command and return any text output on stdout or stderr."""
+    # check=False: don't raise exception, only capture shell error text
+    return subprocess.run(
+        cmd,
+        shell=True,
+        check=False,
+        stderr=subprocess.STDOUT,
+        stdout=subprocess.PIPE,
+    ).stdout.decode()
+
+
 def func(pset):
     # stdout
     print("text on stdout")
+    print(call("ls -l | head -n4"))
+
+    # This will be output on stderr by the shell interpreter, but since (i) we
+    # merge stdout and stderr in call() and (ii) use print() which outputs on
+    # stdout, this will end up there.
+    print(call("xxxyyyzzz will raise shell error"))
 
     # stderr
     print("text on stderr", file=sys.stderr)
@@ -18,13 +37,18 @@ def func(pset):
 if __name__ == "__main__":
     params = ps.plist("a", [1, 2, 3, 4])
 
-    # Write only to disk. No calc/<pset_id>/logs.txt file will be generated.
-    ps.run(func, params, capture_logs="db")
+    # Write only to db. No calc/<pset_id>/logs.txt file will be generated.
+    df = ps.run(func, params, capture_logs="db")
+    print(df._logs.values[-1])
 
-    # Only to file
-    ps.run(func, params, capture_logs="file")
+    # Only to file, print last disk file content from this run
+    df = ps.run(func, params, capture_logs="file")
+    pset_id = df._pset_id.values[-1]
+    # calc_dir is the same for all psets, so just grab the first one
+    calc_dir = df._calc_dir.values[0]
+    # These do the same
+    ##print(call(f"cat {calc_dir}/{pset_id}/logs.txt"))
+    print(ps.file_read(f"{calc_dir}/{pset_id}/logs.txt"))
 
     # Both
     df = ps.run(func, params, capture_logs="db+file")
-
-    ps.df_print(df, cols=["a", "_pset_id", "_run_id", "_logs"])