add support for redirecting output of cloud-init, cloud-config and cloud-final

1 files changed, 109 insertions, 0 deletions

diff --git a/cloudinit/CloudConfig/__init__.py b/cloudinit/CloudConfig/__init__.py
index 6932acbe..22ad63a6 100644
--- a/cloudinit/CloudConfig/__init__.py
+++ b/cloudinit/CloudConfig/__init__.py
@@ -21,6 +21,8 @@ import cloudinit
 import cloudinit.util as util
 import sys
 import traceback
+import os
+import subprocess
 
 per_instance="once-per-instance"
 per_always="always"
@@ -103,3 +105,110 @@ def run_cc_modules(cc,module_list,log):
             failures.append(name)
 
     return(failures)
+
+# always returns well formated values 
+# cfg is expected to have an entry 'output' in it, which is a dictionary
+# that includes entries for 'init', 'config', 'final' or 'all'
+#   init: /var/log/cloud.out
+#   config: [ ">> /var/log/cloud-config.out", /var/log/cloud-config.err ]
+#   final:
+#     output: "| logger -p"
+#     error: "> /dev/null"
+# this returns the specific 'mode' entry, cleanly formatted, with value
+# None if if none is given
+def get_output_cfg(cfg, mode="init"):
+    ret = [ None, None ]
+    if not 'output' in cfg: return ret
+
+    outcfg = cfg['output']
+    if mode in outcfg:
+        modecfg = outcfg[mode]
+    else:
+        if 'all' not in outcfg: return ret
+        # if there is a 'all' item in the output list
+        # then it applies to all users of this (init, config, final)
+        modecfg = outcfg['all']
+
+    # if value is a string, it specifies stdout
+    if isinstance(modecfg,str):
+        ret = [ modecfg, None ]
+
+    # if its a list, then we expect (stdout, stderr)
+    if isinstance(modecfg,list):
+        if len(modecfg) > 0: ret[0] = modecfg[0]
+        if len(modecfg) > 1:
+            ret[1] = modecfg[1]
+
+    # if it is a dictionary, expect 'out' and 'error'
+    # items, which indicate out and error
+    if isinstance(modecfg, dict):
+        if 'output' in modecfg:
+            ret[0] = modecfg['output']
+        if 'error' in modecfg:
+            ret[1] = modecfg['error']
+
+    # if err's entry == "&1", then make it same as stdout
+    # as in shell syntax of "echo foo >/dev/null 2>&1"
+    if ret[1] == "&1": ret[1] = ret[0]
+
+    swlist = [ ">>", ">", "|" ]
+    for i in range(len(ret)):
+        if not ret[i]: continue
+        val = ret[i].lstrip()
+        found = False
+        for s in swlist:
+            if val.startswith(s):
+                val = "%s %s" % (s,val[len(s):].strip())
+                found = True
+                break
+        if not found:
+            # default behavior is append
+            val = "%s %s" % ( ">>", val.strip())
+        ret[i] = val
+
+    return(ret)
+
+    
+# redirect_output(outfmt, errfmt, orig_out, orig_err)
+#  replace orig_out and orig_err with filehandles specified in outfmt or errfmt
+#  fmt can be:
+#   > FILEPATH
+#   >> FILEPATH
+#   | program [ arg1 [ arg2 [ ... ] ] ]
+#
+#   with a '|', arguments are passed to shell, so one level of
+#   shell escape is required.  
+def redirect_output(outfmt,errfmt, o_out=sys.stdout, o_err=sys.stderr):
+    if outfmt:
+        (mode, arg) = outfmt.split(" ",1)
+        if mode == ">" or mode == ">>":
+            owith = "ab"
+            if mode == ">": owith = "wb"
+            new_fp = open(arg, owith)
+        elif mode == "|":
+            proc = subprocess.Popen(arg, shell=True, stdin=subprocess.PIPE)
+            new_fp = proc.stdin
+        else:
+            raise TypeError("invalid type for outfmt: %s" % outfmt)
+
+        if o_out:
+            os.dup2(new_fp.fileno(), o_out.fileno())
+        if errfmt == outfmt:
+            os.dup2(new_fp.fileno(), o_err.fileno())
+            return
+
+    if errfmt:
+        (mode, arg) = errfmt.split(" ",1)
+        if mode == ">" or mode == ">>":
+            owith = "ab"
+            if mode == ">": owith = "wb"
+            new_fp = open(arg, owith)
+        elif mode == "|":
+            proc = subprocess.Popen(arg, shell=True, stdin=subprocess.PIPE)
+            new_fp = proc.stdin
+        else:
+            raise TypeError("invalid type for outfmt: %s" % outfmt)
+
+        if o_err:
+            os.dup2(new_fp.fileno(), o_err.fileno())
+    return