Here's a slightly exotic, expensive solution: solid, crystaline $\ce{CaF2}$ tubing will do the job.
How to get the gas inside, then make a glass seal, is a bit of a challenge though. Surfaces can be optically polished ultra-flat, mated, and locally melted. Ultrasonic friction melting perhaps, or flame or IR. This is an expensive but viable option and would need some development.
According to the Periodic Table of Videos Fluorine Gas found in nature (NEWS) in 2012 existence of naturally occurring fluorine was found in "fetid fluorite" a form of fluorite where natural radioactivity has caused free fluorine to form and migrate within the crystal. The remaining Calcium has already fully reacted with fluorine and is therefore protected from attack.
A tube manufactured from polycrystalline $\ce{CaF2}$ might do the job nicely. It is a common optical material used in certain applications. For example, the UV transparency and resistance to UV damage and darkening (solarization) has made lenses of polycrystalline $\ce{CaF2}$ essential in the smallest dimension micro lithography for fabrication of computer chips.

above: Photonics.com back in 2003: In Search of Calcium Fluoride: Manufacturers face new production challenges as they attempt to meet rising need.

above: From optik-photonic.de Calcium Fluoride Crystals Blanks Offer Highest Transmission Rates at 193 nm and Below
Many sources for polycrystalline calcium fluoride or "$\ce{CaF2}$ glass" exist. Corning is one example, and it is possible that magnesium fluoride would work as well:
Angewandte Chemie International Edition: Secret of “Fetid Fluorite” Aired: Elemental fluorine F2 detected for the first time in a natural mineral:
Florian Kraus of the TU Munich, as well as Jörn Schmedt auf der Günne and Martin Mangstl at the Ludwig Maximilians University in Munich have now obtained direct proof: Elemental fluorine is the guilty party that causes the unpleasant odor. By using 19F nuclear magnetic resonance spectroscopy (NMR spectroscopy), they were able to show for the first time that elemental fluorine is contained in “antozonite”.
How is this possible for such a reactive gas? The researchers explain that “antozonite” contains a tiny amount of uranium that, together with its radioactive daughter nuclides, constantly releases radiation into the surrounding mineral. This causes fluorite to split into calcium and elemental fluorine, forming the calcium clusters that give “antozonite” its dark purple color. The fluorine is contained in tiny enclaves surrounded by nonreactive fluorite, which shields it from the calcium, allowing it to maintain its elemental form.