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Stream tarball uploads

Previously, this would pipe tar's output to curl. But curl would buffer the entire output to memory in order to calculate the content-length header. This pointlessly made large tar backups impossible as the backend does not require a content-length header sent with the data.
master
dave 3 years ago
parent
commit
c3261071f4
3 changed files with 73 additions and 22 deletions
  1. +7
    -2
      README.md
  2. +1
    -1
      datadb/__init__.py
  3. +65
    -19
      datadb/datadb.py

+ 7
- 2
README.md View File

@@ -86,12 +86,17 @@ Restore operations have a degree of sanity checking. Upon a successful restore,

Command line usage is agnostic to the underlying transport protocol used.

### Testing

The following environment variables can be used to ease testing:
### Tips

If available, `pigz` will be selected over gzip. Pigz is a multicore-capable implementation of gzip and is recommended
on multicore machines. See http://zlib.net/pigz/.

The following environment variables can be used to ease testing or deployment:

* DATADB_CONF=./example.ini
* DATADB_KEYPATH=./datadb.key
* DATADB_HTTP_API='http://127.0.0.1:1234/cgi-bin/'

## TODO



+ 1
- 1
datadb/__init__.py View File

@@ -1 +1 @@
__version__ = "0.0.5"
__version__ = "0.0.6"

+ 65
- 19
datadb/datadb.py View File

@@ -13,7 +13,7 @@ from requests import get, put, head
SSH_KEY_PATH = environ["DATADB_KEYPATH"] if "DATADB_KEYPATH" in environ else '/root/.ssh/datadb.key'
RSYNC_DEFAULT_ARGS = ['rsync', '-avzr', '--exclude=.datadb.lock', '--whole-file', '--one-file-system', '--delete', '-e',
'ssh -i {} -p 4874 -o StrictHostKeyChecking=no'.format(SSH_KEY_PATH)]
DATADB_HTTP_API = 'http://datadb.services.davepedu.com:4875/cgi-bin/'
DATADB_HTTP_API = environ.get('DATADB_HTTP_API', 'http://datadb.services.davepedu.com:4875/cgi-bin/')


class SyncStatus(Enum):
@@ -23,6 +23,29 @@ class SyncStatus(Enum):
DATA_MISSING = 2


# Requests will call tell() on the file-like stdout stream if the tell attribute exists. However subprocess'
# stdout stream (_io.BufferedReader) does not support this (raises OSError: [Errno 29] Illegal seek).
# If the tell attribute is missing, requests will fall back to simply iterating on the file-like object,
# so, we support only the iterable interface
class WrappedStdout(object):
BUFFSIZE = 256 * 1024

def __init__(self, stdout):
self.stdout = stdout

def __iter__(self):
return self

def __next__(self):
data = self.stdout.read(self.BUFFSIZE)
if not data:
raise StopIteration()
return data

def close(self):
self.stdout.close()


def restore(profile, conf, force=False): # remote_uri, local_dir, identity='/root/.ssh/datadb.key'
"""
Restore data from datadb
@@ -30,7 +53,8 @@ def restore(profile, conf, force=False): # remote_uri, local_dir, identity='/ro

# Sanity check: If the lockfile exists we assume the data is already there, so we wouldn't want to call rsync again
# as it would wipe out local changes. This can be overridden with --force
assert (status(profile, conf) == SyncStatus.DATA_MISSING) or force, "Data already exists (Use --force?)"
if not ((status(profile, conf) == SyncStatus.DATA_MISSING) or force):
raise Exception("Data already exists (Use --force?)")

original_perms = stat(conf["dir"])
dest = urlparse(conf["uri"])
@@ -72,8 +96,10 @@ def restore(profile, conf, force=False): # remote_uri, local_dir, identity='/ro
extract.wait()
# TODO: convert to pure python?

assert dl.returncode == 0, "Could not download archive"
assert extract.returncode == 0, "Could not extract archive"
if dl.returncode != 0:
raise Exception("Could not download archive")
if extract.returncode != 0:
raise Exception("Could not extract archive")

# Restore original permissions on data dir
# TODO store these in conf file
@@ -89,7 +115,8 @@ def backup(profile, conf, force=False):

# Sanity check: If the lockfile doesn't exist we assume the data is missing, so we wouldn't want to call rsync
# again as it would wipe out the backup.
assert (status(profile, conf) == SyncStatus.DATA_AVAILABLE) or force, "Data is missing (Use --force?)"
if not ((status(profile, conf) == SyncStatus.DATA_AVAILABLE) or force):
raise Exception("Data is missing (Use --force?)")

dest = urlparse(conf["uri"])

@@ -132,10 +159,16 @@ def backup(profile, conf, force=False):

elif dest.scheme == 'archive':
# CD to local source dir
# create tarball
# http PUT file to backup server
# tar+gz data and stream to backup server
args_tar = ['tar', '--exclude=.datadb.lock']

# Use pigz if available (Parallel gzip - http://zlib.net/pigz/)
if has_binary("pigz"):
args_tar += ["--use-compress-program", "pigz"]
else:
args_tar += ["-z"]

# Excluded paths
if conf["exclude"]:
for exclude_path in conf["exclude"].split(","):
@@ -143,21 +176,22 @@ def backup(profile, conf, force=False):
args_tar.append("--exclude")
args_tar.append(exclude_path)

args_tar += ['-zcv', './']
args_curl = ['curl', '-v', '-XPUT', '--data-binary', '@-', '{}new_backup?proto=archive&name={}&keep={}'.
format(DATADB_HTTP_API, profile, conf["keep"])]
args_tar += ['-cv', './']
tar_dir = normpath(conf["dir"]) + '/'
print("Tar call in {}: {}".format(args_tar, tar_dir))

print("Tar backup call: {} | {}".format(' '.join(args_tar), ' '.join(args_curl)))
tar = subprocess.Popen(args_tar, stdout=subprocess.PIPE, cwd=tar_dir)

compress = subprocess.Popen(args_tar, stdout=subprocess.PIPE, cwd=normpath(conf["dir"]) + '/')
upload = subprocess.Popen(args_curl, stdin=compress.stdout)
put_url = '{}new_backup?proto=archive&name={}&keep={}'.format(DATADB_HTTP_API, profile, conf["keep"])
print("Putting to: {}".format(put_url))

compress.wait()
upload.wait()
# TODO: convert to pure python?
upload = put(put_url, data=WrappedStdout(tar.stdout))
if upload.status_code != 200:
raise Exception("Upload failed with code: {}".format(upload.status_code))

assert compress.returncode == 0, "Could not create archive"
assert upload.returncode == 0, "Could not upload archive"
tar.wait()
if tar.returncode != 0:
raise Exception("Tar process exited with nonzero code {}".format(tar.returncode))


def status(profile, conf):
@@ -180,6 +214,18 @@ def shell_exec(cmd, workdir='/tmp/'):
subprocess.Popen(cmd, shell=True, cwd=workdir).wait()


def has_binary(name):
"""
Check if the passed command is available
:return: boolean
"""
try:
subprocess.check_call(['which', name], stdout=subprocess.DEVNULL)
except subprocess.CalledProcessError:
return False
return True


def main():
"""
Excepts a config file at /etc/datadb.ini. Example:
@@ -302,7 +348,7 @@ def main():
if not args.no_pre_exec and config[args.profile]['export_preexec']:
shell_exec(config[args.profile]['export_preexec'])

backup(args.profile, config[args.profile])
backup(args.profile, config[args.profile], force=args.force)

if not args.no_post_exec and config[args.profile]['export_postexec']:
shell_exec(config[args.profile]['export_postexec'])


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