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About

Storing and reading BLOBs to and from a cloud service. The project will consist of a library, command line tool, Apache HTTP Server module and an Nginx module. Currently, the command line tool is work in progress.

Building

  • cmake
  • APR, APR Util
  • cURL
  • OpenSSL

Releases and Downloads

See Releases

Usage

The command line tool is controlled via env variables and command line arguments. Command line arguments take priority and overwrite env variables settings. If the action is set to WRITE_BLOB and neither MCS_PATH_TO_FILE nor --path_to_file is specified, the command line tool tries to read from stdin. Similarly, when then action is set to READ_BLOB, and neither MCS_PATH_TO_FILE nor --path_to_file is specified, the command line tool writes the blob contents to stdout.

Env variables

MCS_ACTION=READ_BLOB|WRITE_BLOB|DELETE_BLOB|LIST_BLOBS|CREATE_CONTAINER
MCS_AZURE_STORAGE_KEY=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==
MCS_AZURE_STORAGE_ACCOUNT=devstoreaccount1
MCS_AZURE_BLOB_NAME=test
MCS_AZURE_CONTAINER=your-container
MCS_PATH_TO_FILE=/tmp/meh
MCS_BLOB_STORE_URL=127.0.0.1:10000
MCS_TEST_REGIME=true|false

Command line arguments

--action
--azure_storage_key
--azure_storage_account
--blob_name
--azure_container
--path_to_file
--blob_store_url
--test_regime

Testing and fooling around

Creating a container

./mod_cloud_storage \
--action CREATE_CONTAINER \
--azure_storage_key Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw== \
--azure_storage_account devstoreaccount1 \
--azure_container my-first-container \
--blob_store_url 127.0.0.1:10000 \
--test_regime true

Note the storage account is always called devstoreaccount1 by definition in all Azure Storage emulator implementations. The same holds for the storage key. Container and blob names are arbitrary.

Writing a BLOB to the container

  • Let's create a test file, e.g. echo "Silence is golden." > /tmp/test
./mod_cloud_storage \
--action WRITE_BLOB \
--azure_storage_key 'Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==' \
--azure_storage_account 'devstoreaccount1' \
--azure_container mod-cloud-storage \
--blob_store_url localhost:10000 \
--test_regime true \
--blob_name 'testblob' < /tmp/test

Output (DEBUG):

Reading from stdin
BLOB to be uploaded length: 19
BLOB to be uploaded MD5sum base64: YmT6qz9/oJawL1eym/1EQQ==
BLOB to be uploaded MD5sum hex:    6264faab3f7fa096b02f57b29bfd4441
 libcurl said: No error
Response Code: 201
Response Body followed by \n:(null)

Note the tool is reading from stdin via pipe now ...< /tmp/test. One could use either MCS_PATH_TO_FILE env var or --path_to_file parameter instead. If all aforementioned is specified, parameter takes precedence over env var and env var takes precedence over stdin.

Reading the BLOB from the container

./mod_cloud_storage \
--action READ_BLOB \
--azure_storage_key 'Eby8vdM02xNOcqFlqUwJPLlm\EtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/\K1SZFPTOtr/KBHBeksoGMGw==' \
--azure_storage_account 'devstoreaccount1' \
--azure_container mod-cloud-storage \
--blob_store_url localhost:10000 \
--test_regime true \
--blob_name 'testblob'

Neither MCS_PATH_TO_FILE nor --path_to_file was specified, so the content of the BLOB was written to stdout. Output (DEBUG):

 libcurl said: No error
Response Code: 200
Response Body followed by \n:Silence is golden.

Note that if a path to the file is specified, the content of the file is overwritten, not appended to.

Deleting the BLOB from the container

Exactly the same as reading the BLOB but for the action parameter:

--action DELETE_BLOB

Output (DEBUG):

 libcurl said: No error
Response Code: 202
Response Body followed by \n:(null)

Note that the current implementation deletes all blob's snapshots too. Regarding leases, the current implementation does not deal with leases on blobs, so if there is a lease on the blob, the delete action fails.

Working with a real Azure storage

  • Create your Azure profile if you don't have one.
  • Create a Storage account if you don't have one, Name, Resource group, all arbitrary. If you need help with this terminology, read Azure Storage manual. In this example, we use new Storage account karmdelete.

  • Copy your Account name and one of the two Storage keys.

  • You are ready to use the command line tool now. First, create a container called, e.g. my-first-container. 
    ./mod_cloud_storage \
--action CREATE_CONTAINER \
--azure_storage_key 'YourStorageKey' \
--azure_storage_account karmdelete \
--azure_container my-first-container
  • Let's create a test file, e.g. echo "Silence is golden." > /tmp/test
  • Upload the file as a BLOB called e.g. testblob to your container my-first-container within your Storage account karmdelete. 
    ./mod_cloud_storage \
--action WRITE_BLOB \
--azure_storage_key 'YourStorageKey' \
--azure_storage_account karmdelete \
--azure_container my-first-container \
--blob_name 'testblob' \
--path_to_file /tmp/test
    Output (DEBUG): 
    Reading from file.
BLOB to be uploaded length: 19
BLOB to be uploaded MD5sum base64: YmT6qz9/oJawL1eym/1EQQ==
BLOB to be uploaded MD5sum hex:    6264faab3f7fa096b02f57b29bfd4441
 libcurl said: No error
Response Code: 201
Response Body followed by \n:(null)
  • One may check the result on Azure Portal, click on Blobs in your Storage account:

  • If you download the blob, it contains 19 bytes "Silence is golden.\n"
  • Let's read the contents of the BLOB with READ_BLOB action: 
    ./mod_cloud_storage \
--action READ_BLOB \
--azure_storage_key 'YourStorageKey' \
--azure_storage_account karmdelete \
--azure_container my-first-container \
--blob_name 'testblob' \
--path_to_file /tmp/test_out
    Output (DEBUG): 
     libcurl said: No error
Response Code: 200
Writing to file: /tmp/test_out
19 bytes of response written to /tmp/test_out.
  • One can delete the aforementioned blob with the same command as for reading it but for the action attribute which is supposed to change to: DELETE_BLOB.
  • Do not use a storage account with valuable containers in it. This tool is just a toy.