Buildah push writes to stderr

[kanadaj]

---

BUG REPORT INFORMATION

Description

buildah push on Azure Pipelines seems to write to stderr even though there is no indication of an error. This makes it so failOnStderr cannot be used to abort a release if the pipeline fails to push the built image.

Steps to reproduce the issue:

1. Build image with buildah bud
2. Push image with

   script: |
   buildah login ...
   buildah push --digestfile $(Build.ArtifactStagingDirectory)/dockerbuild.version $(registry)/$(dockerId)/$(imageName)
   cat $(Build.ArtifactStagingDirectory)/dockerbuild.version
   buildah rmi $(registry)/$(dockerId)/$(imageName)

Describe the results you received:

========================== Starting Command Output ===========================
/usr/bin/bash --noprofile --norc /azp/agent/_work/_temp/9dae59d5-0922-417d-847c-becdfa882835.sh
Login Succeeded!
Getting image source signatures
Copying blob sha256:361f4057ac8b2ff4e83ea3092fe3eef0890bf68f64cd2afe6feb1b55998789cd
Copying blob sha256:fbbb67d8b18e50c144bab27fe7615ae347a1e85a57bad97fc2d698cb114ccfab
Copying blob sha256:9189ce99e67946b3810a649fd02d0cee88ce4f81240032955be72ee4bc0a5306
Copying blob sha256:cb381a32b2296e4eb5af3f84092a2e6685e88adbc54ee0768a1a1010ce6376c7
Copying blob sha256:c9d3c9eabfef55d3a851b7ceb658a8c2dbe8d46a16e187cf7998957d95150427
Copying config sha256:6c5458ada8f18120f7cfc3face029a0c1fdfe46a38d9e365ca4d3538152c944c
Writing manifest to image destination
Storing signatures
sha256:910ca799bf4e64ddab728483385c9f83f05e63b2c7a471c756fb0ddbd1ab33d7untagged: [REDACTED]/website:latest
6c5458ada8f18120f7cfc3face029a0c1fdfe46a38d9e365ca4d3538152c944c
##[error]Bash wrote one or more lines to the standard error stream.
##[error]Getting image source signatures

##[error]Copying blob sha256:361f4057ac8b2ff4e83ea3092fe3eef0890bf68f64cd2afe6feb1b55998789cd

##[error]Copying blob sha256:fbbb67d8b18e50c144bab27fe7615ae347a1e85a57bad97fc2d698cb114ccfab

##[error]Copying blob sha256:9189ce99e67946b3810a649fd02d0cee88ce4f81240032955be72ee4bc0a5306

##[error]Copying blob sha256:cb381a32b2296e4eb5af3f84092a2e6685e88adbc54ee0768a1a1010ce6376c7

##[error]Copying blob sha256:c9d3c9eabfef55d3a851b7ceb658a8c2dbe8d46a16e187cf7998957d95150427

##[error]Copying config sha256:6c5458ada8f18120f7cfc3face029a0c1fdfe46a38d9e365ca4d3538152c944c

##[error]Writing manifest to image destination

##[error]Storing signatures

Describe the results you expected:

Output results only to stdout, I see no reason for an error anywhere in that code above, and disabling failOnStderr leads to a successful release.

Output of rpm -q buildah or apt list buildah:

# apt list buildah
Listing... Done
buildah/unknown,now 1.19.2~1 amd64 [installed]
buildah/unknown 1.19.2~1 arm64
buildah/unknown 1.19.2~1 armhf
buildah/unknown 1.19.2~1 s390x

Output of buildah version:

Version:         1.19.2
Go Version:      go1.15.2
Image Spec:      1.0.1-dev
Runtime Spec:    1.0.2-dev
CNI Spec:        0.4.0
libcni Version:  
image Version:   5.9.0
Git Commit:      
Built:           Thu Jan  1 00:00:00 1970
OS/Arch:         linux/amd64

*Output of `cat /etc/release`:**

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"
NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=foca

Output of uname -a:

Linux build-agent-6544dc7f9c-2x7s7 5.4.0-62-generic #70-Ubuntu SMP Tue Jan 12 12:45:47 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Output of cat /etc/containers/storage.conf:

# This file is is the configuration file for all tools
# that use the containers/storage library.
# See man 5 containers-storage.conf for more information
# The "container storage" table contains all of the server options.
[storage]

# Default Storage Driver, Must be set for proper operation.
driver = "overlay"

# Temporary storage location
runroot = "/run/containers/storage"

# Primary Read/Write location of container storage
graphroot = "/var/lib/containers/storage"

# Storage path for rootless users
#
# rootless_storage_path = "$HOME/.local/share/containers/storage"

[storage.options]
# Storage options to be passed to underlying storage drivers

# AdditionalImageStores is used to pass paths to additional Read/Only image stores
# Must be comma separated list.
additionalimagestores = [
]

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to the UIDs/GIDs as they should appear outside of the container,
# and the length of the range of UIDs/GIDs.  Additional mapped sets can be
# listed and will be heeded by libraries, but there are limits to the number of
# mappings which the kernel will allow when you later attempt to run a
# container.
#
# remap-uids = 0:1668442479:65536
# remap-gids = 0:1668442479:65536

# Remap-User/Group is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
# with an in-container ID of 0 and then a host-level ID taken from the lowest
# range that matches the specified name, and using the length of that range.
# Additional ranges are then assigned, using the ranges which specify the
# lowest host-level IDs first, to the lowest not-yet-mapped in-container ID,
# until all of the entries have been used for maps.
#
# remap-user = "containers"
# remap-group = "containers"

# Root-auto-userns-user is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid and /etc/subgid file.  These ranges will be partitioned
# to containers configured to create automatically a user namespace.  Containers
# configured to automatically create a user namespace can still overlap with containers
# having an explicit mapping set.
# This setting is ignored when running as rootless.
# root-auto-userns-user = "storage"
#
# Auto-userns-min-size is the minimum size for a user namespace created automatically.
# auto-userns-min-size=1024
#
# Auto-userns-max-size is the minimum size for a user namespace created automatically.
# auto-userns-max-size=65536

[storage.options.overlay]
# ignore_chown_errors can be set to allow a non privileged user running with
# a single UID within a user namespace to run containers. The user can pull
# and use any image even those with multiple uids.  Note multiple UIDs will be
# squashed down to the default uid in the container.  These images will have no
# separation between the users in the container. Only supported for the overlay
# and vfs drivers.
#ignore_chown_errors = "false"

# Path to an helper program to use for mounting the file system instead of mounting it
# directly.
#mount_program = "/usr/bin/fuse-overlayfs"

# mountopt specifies comma separated list of extra mount options
mountopt = "nodev"

# Set to skip a PRIVATE bind mount on the storage home directory.
# skip_mount_home = "false"

# Size is used to set a maximum size of the container image.
# size = ""

# ForceMask specifies the permissions mask that is used for new files and
# directories.
#
# The values "shared" and "private" are accepted.
# Octal permission masks are also accepted.
#
#  "": No value specified.
#     All files/directories, get set with the permissions identified within the
#     image.
#  "private": it is equivalent to 0700.
#     All files/directories get set with 0700 permissions.  The owner has rwx
#     access to the files. No other users on the system can access the files.
#     This setting could be used with networked based homedirs.
#  "shared": it is equivalent to 0755.
#     The owner has rwx access to the files and everyone else can read, access
#     and execute them. This setting is useful for sharing containers storage
#     with other users.  For instance have a storage owned by root but shared
#     to rootless users as an additional store.
#     NOTE:  All files within the image are made readable and executable by any
#     user on the system. Even /etc/shadow within your image is now readable by
#     any user.
#
#   OCTAL: Users can experiment with other OCTAL Permissions.
#
#  Note: The force_mask Flag is an experimental feature, it could change in the
#  future.  When "force_mask" is set the original permission mask is stored in
#  the "user.containers.override_stat" xattr and the "mount_program" option must
#  be specified. Mount programs like "/usr/bin/fuse-overlayfs" present the
#  extended attribute permissions to processes within containers rather then the
#  "force_mask"  permissions.
#
# force_mask = ""

[storage.options.thinpool]
# Storage Options for thinpool

# autoextend_percent determines the amount by which pool needs to be
# grown. This is specified in terms of % of pool size. So a value of 20 means
# that when threshold is hit, pool will be grown by 20% of existing
# pool size.
# autoextend_percent = "20"

# autoextend_threshold determines the pool extension threshold in terms
# of percentage of pool size. For example, if threshold is 60, that means when
# pool is 60% full, threshold has been hit.
# autoextend_threshold = "80"

# basesize specifies the size to use when creating the base device, which
# limits the size of images and containers.
# basesize = "10G"

# blocksize specifies a custom blocksize to use for the thin pool.
# blocksize="64k"

# directlvm_device specifies a custom block storage device to use for the
# thin pool. Required if you setup devicemapper.
# directlvm_device = ""

# directlvm_device_force wipes device even if device already has a filesystem.
# directlvm_device_force = "True"

# fs specifies the filesystem type to use for the base device.
# fs="xfs"

# log_level sets the log level of devicemapper.
# 0: LogLevelSuppress 0 (Default)
# 2: LogLevelFatal
# 3: LogLevelErr
# 4: LogLevelWarn
# 5: LogLevelNotice
# 6: LogLevelInfo
# 7: LogLevelDebug
# log_level = "7"

# min_free_space specifies the min free space percent in a thin pool require for
# new device creation to succeed. Valid values are from 0% - 99%.
# Value 0% disables
# min_free_space = "10%"

# mkfsarg specifies extra mkfs arguments to be used when creating the base
# device.
# mkfsarg = ""

# metadata_size is used to set the `pvcreate --metadatasize` options when
# creating thin devices. Default is 128k
# metadata_size = ""

# Size is used to set a maximum size of the container image.
# size = ""

# use_deferred_removal marks devicemapper block device for deferred removal.
# If the thinpool is in use when the driver attempts to remove it, the driver
# tells the kernel to remove it as soon as possible. Note this does not free
# up the disk space, use deferred deletion to fully remove the thinpool.
# use_deferred_removal = "True"

# use_deferred_deletion marks thinpool device for deferred deletion.
# If the device is busy when the driver attempts to delete it, the driver
# will attempt to delete device every 30 seconds until successful.
# If the program using the driver exits, the driver will continue attempting
# to cleanup the next time the driver is used. Deferred deletion permanently
# deletes the device and all data stored in device will be lost.
# use_deferred_deletion = "True"

# xfs_nospace_max_retries specifies the maximum number of retries XFS should
# attempt to complete IO when ENOSPC (no space) error is returned by
# underlying storage device.
# xfs_nospace_max_retries = "0

[vrothberg]

Thanks for reaching out.

You can use --quiet to suppress the output altogether. That should help resolve the immediate issue.

The behavior is consistent across Podman and Buildah, but Docker does not write to stderr unless there's an error. @rhatdan, do you recall what the reasoning was?

[giuseppe]

I think stderr is the correct behavior, stderr is not meant only for errors but also for diagnostic messages

[rhatdan]

Yes the idea was to allow users to get the image id, while the rest was diagnostic.

imageid=$(buildah bud /tmp/)

[kanadaj]

@rhatdan I feel it'd be better for CI/CD systems to be able to direct diagnostics to stdout to be able to detect errors just by listening to stderr, a flag would be nice for this.

[rhatdan]

Interested in opening a PR?

[kanadaj]

Buildah's internals are incredibly alien to me, I would do it otherwise but it'd probably take me far too long :(

[rhatdan]

Well in Bash this is fairly easy to redirect stderr to stdout

buildah push ... 2>&1

Or turn off the push processing with

buildah push -q ...

So I am going to close this as wont fix.